CREATE TABLE

CREATE TABLE

7

SQL - Language Statements

CREATE TABLE

define a new table

CREATE \[ \[ GLOBAL \| LOCAL \] { TEMPORARY \| TEMP } \| UNLOGGED \]
TABLE \[ IF NOT EXISTS \]

table\_name

( \[ {

column\_name

data\_type

\[ COMPRESSION

compression\_method

\] \[ COLLATE

collation

\] \[

column\_constraint

\[ \... \] \] \|

table\_constraint

\| LIKE

source\_table

\[

like\_option

\... \] } \[, \... \] \] ) \[ INHERITS (

parent\_table

\[, \... \] ) \] \[ PARTITION BY { RANGE \| LIST \| HASH } ( {

column\_name

\| (

expression

) } \[ COLLATE

collation

\] \[

opclass

\] \[, \... \] ) \] \[ USING

method

\] \[ WITH (

storage\_parameter

\[=

value

\] \[, \... \] ) \| WITHOUT OIDS \] \[ ON COMMIT { PRESERVE ROWS \|
DELETE ROWS \| DROP } \] \[ TABLESPACE

tablespace\_name

\] CREATE \[ \[ GLOBAL \| LOCAL \] { TEMPORARY \| TEMP } \| UNLOGGED \]
TABLE \[ IF NOT EXISTS \]

table\_name

OF

type\_name

\[ ( {

column\_name

\[ WITH OPTIONS \] \[

column\_constraint

\[ \... \] \] \|

table\_constraint

} \[, \... \] ) \] \[ PARTITION BY { RANGE \| LIST \| HASH } ( {

column\_name

\| (

expression

) } \[ COLLATE

collation

\] \[

opclass

\] \[, \... \] ) \] \[ USING

method

\] \[ WITH (

storage\_parameter

\[=

value

\] \[, \... \] ) \| WITHOUT OIDS \] \[ ON COMMIT { PRESERVE ROWS \|
DELETE ROWS \| DROP } \] \[ TABLESPACE

tablespace\_name

\] CREATE \[ \[ GLOBAL \| LOCAL \] { TEMPORARY \| TEMP } \| UNLOGGED \]
TABLE \[ IF NOT EXISTS \]

table\_name

PARTITION OF

parent\_table

\[ ( {

column\_name

\[ WITH OPTIONS \] \[

column\_constraint

\[ \... \] \] \|

table\_constraint

} \[, \... \] ) \] { FOR VALUES

partition\_bound\_spec

\| DEFAULT } \[ PARTITION BY { RANGE \| LIST \| HASH } ( {

column\_name

\| (

expression

) } \[ COLLATE

collation

\] \[

opclass

\] \[, \... \] ) \] \[ USING

method

\] \[ WITH (

storage\_parameter

\[=

value

\] \[, \... \] ) \| WITHOUT OIDS \] \[ ON COMMIT { PRESERVE ROWS \|
DELETE ROWS \| DROP } \] \[ TABLESPACE

tablespace\_name

\]

where

column\_constraint

is:

\[ CONSTRAINT

constraint\_name

\] { NOT NULL \| NULL \| CHECK (

expression

) \[ NO INHERIT \] \| DEFAULT

default\_expr

\| GENERATED ALWAYS AS (

generation\_expr

) STORED \| GENERATED { ALWAYS \| BY DEFAULT } AS IDENTITY \[ (

sequence\_options

) \] \| UNIQUE \[ NULLS \[ NOT \] DISTINCT \]

index\_parameters

\| PRIMARY KEY

index\_parameters

\| REFERENCES

reftable

\[ (

refcolumn

) \] \[ MATCH FULL \| MATCH PARTIAL \| MATCH SIMPLE \] \[ ON DELETE

referential\_action

\] \[ ON UPDATE

referential\_action

\] } \[ DEFERRABLE \| NOT DEFERRABLE \] \[ INITIALLY DEFERRED \|
INITIALLY IMMEDIATE \]

and

table\_constraint

is:

\[ CONSTRAINT

constraint\_name

\] { CHECK (

expression

) \[ NO INHERIT \] \| UNIQUE \[ NULLS \[ NOT \] DISTINCT \] (

column\_name

\[, \... \] )

index\_parameters

\| PRIMARY KEY (

column\_name

\[, \... \] )

index\_parameters

\| EXCLUDE \[ USING

index\_method

\] (

exclude\_element

WITH

operator

\[, \... \] )

index\_parameters

\[ WHERE (

predicate

) \] \| FOREIGN KEY (

column\_name

\[, \... \] ) REFERENCES

reftable

\[ (

refcolumn

\[, \... \] ) \] \[ MATCH FULL \| MATCH PARTIAL \| MATCH SIMPLE \] \[ ON
DELETE

referential\_action

\] \[ ON UPDATE

referential\_action

\] } \[ DEFERRABLE \| NOT DEFERRABLE \] \[ INITIALLY DEFERRED \|
INITIALLY IMMEDIATE \]

and

like\_option

is:

{ INCLUDING \| EXCLUDING } { COMMENTS \| COMPRESSION \| CONSTRAINTS \|
DEFAULTS \| GENERATED \| IDENTITY \| INDEXES \| STATISTICS \| STORAGE \|
ALL }

and

partition\_bound\_spec

is:

IN (

partition\_bound\_expr

\[, \...\] ) \| FROM ( {

partition\_bound\_expr

\| MINVALUE \| MAXVALUE } \[, \...\] ) TO ( {

partition\_bound\_expr

\| MINVALUE \| MAXVALUE } \[, \...\] ) \| WITH ( MODULUS

numeric\_literal

, REMAINDER

numeric\_literal

)

index\_parameters

in

UNIQUE

,

PRIMARY KEY

, and

EXCLUDE

constraints are:

\[ INCLUDE (

column\_name

\[, \... \] ) \] \[ WITH (

storage\_parameter

\[=

value

\] \[, \... \] ) \] \[ USING INDEX TABLESPACE

tablespace\_name

\]

exclude\_element

in an

EXCLUDE

constraint is:

{

column\_name

\| (

expression

) } \[

opclass

\] \[ ASC \| DESC \] \[ NULLS { FIRST \| LAST } \]

referential\_action

in a

FOREIGN KEY

/

REFERENCES

constraint is:

{ NO ACTION \| RESTRICT \| CASCADE \| SET NULL \[ (

column\_name

\[, \... \] ) \] \| SET DEFAULT \[ (

column\_name

\[, \... \] ) \] }

Description {#sql-createtable-description}
===========

`CREATE TABLE` will create a new, initially empty table in the current
database. The table will be owned by the user issuing the command.

If a schema name is given (for example, `CREATE TABLE
   myschema.mytable ...`) then the table is created in the specified
schema. Otherwise it is created in the current schema. Temporary tables
exist in a special schema, so a schema name cannot be given when
creating a temporary table. The name of the table must be distinct from
the name of any other relation (table, sequence, index, view,
materialized view, or foreign table) in the same schema.

`CREATE TABLE` also automatically creates a data type that represents
the composite type corresponding to one row of the table. Therefore,
tables cannot have the same name as any existing data type in the same
schema.

The optional constraint clauses specify constraints (tests) that new or
updated rows must satisfy for an insert or update operation to succeed.
A constraint is an SQL object that helps define the set of valid values
in the table in various ways.

There are two ways to define constraints: table constraints and column
constraints. A column constraint is defined as part of a column
definition. A table constraint definition is not tied to a particular
column, and it can encompass more than one column. Every column
constraint can also be written as a table constraint; a column
constraint is only a notational convenience for use when the constraint
only affects one column.

To be able to create a table, you must have `USAGE` privilege on all
column types or the type in the `OF` clause, respectively.

Parameters
==========

`TEMPORARY` or `TEMP`

:   If specified, the table is created as a temporary table. Temporary
    tables are automatically dropped at the end of a session, or
    optionally at the end of the current transaction (see `ON COMMIT`
    below). The default search\_path includes the temporary schema first
    and so identically named existing permanent tables are not chosen
    for new plans while the temporary table exists, unless they are
    referenced with schema-qualified names. Any indexes created on a
    temporary table are automatically temporary as well.

    The [autovacuum daemon](#autovacuum) cannot access and therefore
    cannot vacuum or analyze temporary tables. For this reason,
    appropriate vacuum and analyze operations should be performed via
    session SQL commands. For example, if a temporary table is going to
    be used in complex queries, it is wise to run `ANALYZE` on the
    temporary table after it is populated.

    Optionally, `GLOBAL` or `LOCAL` can be written before `TEMPORARY` or
    `TEMP`. This presently makes no difference in PostgreSQL and is
    deprecated; see [Compatibility](#sql-createtable-compatibility)
    below.

`UNLOGGED`

:   If specified, the table is created as an unlogged table. Data
    written to unlogged tables is not written to the write-ahead log
    (see [???](#wal)), which makes them considerably faster than
    ordinary tables. However, they are not crash-safe: an unlogged table
    is automatically truncated after a crash or unclean shutdown. The
    contents of an unlogged table are also not replicated to standby
    servers. Any indexes created on an unlogged table are automatically
    unlogged as well.

    If this is specified, any sequences created together with the
    unlogged table (for identity or serial columns) are also created as
    unlogged.

`IF NOT EXISTS`

:   Do not throw an error if a relation with the same name already
    exists. A notice is issued in this case. Note that there is no
    guarantee that the existing relation is anything like the one that
    would have been created.

table\_name

:   The name (optionally schema-qualified) of the table to be created.

`OF type_name`

:   Creates a typed table, which takes its structure from the specified
    composite type (name optionally schema-qualified). A typed table is
    tied to its type; for example the table will be dropped if the type
    is dropped (with `DROP TYPE ... CASCADE`).

    When a typed table is created, then the data types of the columns
    are determined by the underlying composite type and are not
    specified by the `CREATE TABLE` command. But the `CREATE TABLE`
    command can add defaults and constraints to the table and can
    specify storage parameters.

column\_name

:   The name of a column to be created in the new table.

data\_type

:   The data type of the column. This can include array specifiers. For
    more information on the data types supported by PostgreSQL, refer to
    [???](#datatype).

`COLLATE collation`

:   The `COLLATE` clause assigns a collation to the column (which must
    be of a collatable data type). If not specified, the column data
    type\'s default collation is used.

`COMPRESSION compression_method`

:   The `COMPRESSION` clause sets the compression method for the column.
    Compression is supported only for variable-width data types, and is
    used only when the column\'s storage mode is `main` or `extended`.
    (See [???](#sql-altertable) for information on column storage
    modes.) Setting this property for a partitioned table has no direct
    effect, because such tables have no storage of their own, but the
    configured value will be inherited by newly-created partitions. The
    supported compression methods are `pglz` and `lz4`. (`lz4` is
    available only if `--with-lz4` was used when building PostgreSQL.)
    In addition, compression\_method can be `default` to explicitly
    specify the default behavior, which is to consult the
    [???](#guc-default-toast-compression) setting at the time of data
    insertion to determine the method to use.

`INHERITS ( parent_table [, ... ] )`

:   The optional `INHERITS` clause specifies a list of tables from which
    the new table automatically inherits all columns. Parent tables can
    be plain tables or foreign tables.

    Use of `INHERITS` creates a persistent relationship between the new
    child table and its parent table(s). Schema modifications to the
    parent(s) normally propagate to children as well, and by default the
    data of the child table is included in scans of the parent(s).

    If the same column name exists in more than one parent table, an
    error is reported unless the data types of the columns match in each
    of the parent tables. If there is no conflict, then the duplicate
    columns are merged to form a single column in the new table. If the
    column name list of the new table contains a column name that is
    also inherited, the data type must likewise match the inherited
    column(s), and the column definitions are merged into one. If the
    new table explicitly specifies a default value for the column, this
    default overrides any defaults from inherited declarations of the
    column. Otherwise, any parents that specify default values for the
    column must all specify the same default, or an error will be
    reported.

    `CHECK` constraints are merged in essentially the same way as
    columns: if multiple parent tables and/or the new table definition
    contain identically-named `CHECK` constraints, these constraints
    must all have the same check expression, or an error will be
    reported. Constraints having the same name and expression will be
    merged into one copy. A constraint marked `NO INHERIT` in a parent
    will not be considered. Notice that an unnamed `CHECK` constraint in
    the new table will never be merged, since a unique name will always
    be chosen for it.

    Column `STORAGE` settings are also copied from parent tables.

    If a column in the parent table is an identity column, that property
    is not inherited. A column in the child table can be declared
    identity column if desired.

`PARTITION BY { RANGE | LIST | HASH } ( { column_name | ( expression ) } [ opclass ] [, ...] ) `

:   The optional `PARTITION BY` clause specifies a strategy of
    partitioning the table. The table thus created is called a
    partitioned table. The parenthesized list of columns or expressions
    forms the partition key for the table. When using range or hash
    partitioning, the partition key can include multiple columns or
    expressions (up to 32, but this limit can be altered when building
    PostgreSQL), but for list partitioning, the partition key must
    consist of a single column or expression.

    Range and list partitioning require a btree operator class, while
    hash partitioning requires a hash operator class. If no operator
    class is specified explicitly, the default operator class of the
    appropriate type will be used; if no default operator class exists,
    an error will be raised. When hash partitioning is used, the
    operator class used must implement support function 2 (see
    [???](#xindex-support) for details).

    A partitioned table is divided into sub-tables (called partitions),
    which are created using separate `CREATE TABLE` commands. The
    partitioned table is itself empty. A data row inserted into the
    table is routed to a partition based on the value of columns or
    expressions in the partition key. If no existing partition matches
    the values in the new row, an error will be reported.

    Partitioned tables do not support `EXCLUDE` constraints; however,
    you can define these constraints on individual partitions.

    See [???](#ddl-partitioning) for more discussion on table
    partitioning.

`PARTITION OF parent_table { FOR VALUES partition_bound_spec | DEFAULT }`

:   Creates the table as a partition of the specified parent table. The
    table can be created either as a partition for specific values using
    `FOR VALUES` or as a default partition using `DEFAULT`. Any indexes,
    constraints and user-defined row-level triggers that exist in the
    parent table are cloned on the new partition.

    The partition\_bound\_spec must correspond to the partitioning
    method and partition key of the parent table, and must not overlap
    with any existing partition of that parent. The form with `IN` is
    used for list partitioning, the form with `FROM` and `TO` is used
    for range partitioning, and the form with `WITH` is used for hash
    partitioning.

    partition\_bound\_expr is any variable-free expression (subqueries,
    window functions, aggregate functions, and set-returning functions
    are not allowed). Its data type must match the data type of the
    corresponding partition key column. The expression is evaluated once
    at table creation time, so it can even contain volatile expressions
    such as `CURRENT_TIMESTAMP`.

    When creating a list partition, `NULL` can be specified to signify
    that the partition allows the partition key column to be null.
    However, there cannot be more than one such list partition for a
    given parent table. `NULL` cannot be specified for range partitions.

    When creating a range partition, the lower bound specified with
    `FROM` is an inclusive bound, whereas the upper bound specified with
    `TO` is an exclusive bound. That is, the values specified in the
    `FROM` list are valid values of the corresponding partition key
    columns for this partition, whereas those in the `TO` list are not.
    Note that this statement must be understood according to the rules
    of row-wise comparison ([???](#row-wise-comparison)). For example,
    given `PARTITION BY RANGE (x,y)`, a partition bound
    `FROM (1, 2) TO (3, 4)` allows `x=1` with any `y>=2`, `x=2` with any
    non-null `y`, and `x=3` with any `y<4`.

    The special values `MINVALUE` and `MAXVALUE` may be used when
    creating a range partition to indicate that there is no lower or
    upper bound on the column\'s value. For example, a partition defined
    using `FROM (MINVALUE) TO (10)` allows any values less than 10, and
    a partition defined using `FROM (10) TO (MAXVALUE)` allows any
    values greater than or equal to 10.

    When creating a range partition involving more than one column, it
    can also make sense to use `MAXVALUE` as part of the lower bound,
    and `MINVALUE` as part of the upper bound. For example, a partition
    defined using `FROM (0, MAXVALUE) TO (10, MAXVALUE)` allows any rows
    where the first partition key column is greater than 0 and less than
    or equal to 10. Similarly, a partition defined using
    `FROM ('a', MINVALUE) TO ('b', MINVALUE)` allows any rows where the
    first partition key column starts with \"a\".

    Note that if `MINVALUE` or `MAXVALUE` is used for one column of a
    partitioning bound, the same value must be used for all subsequent
    columns. For example, `(10, MINVALUE, 0)` is not a valid bound; you
    should write `(10, MINVALUE, MINVALUE)`.

    Also note that some element types, such as `timestamp`, have a
    notion of \"infinity\", which is just another value that can be
    stored. This is different from `MINVALUE` and `MAXVALUE`, which are
    not real values that can be stored, but rather they are ways of
    saying that the value is unbounded. `MAXVALUE` can be thought of as
    being greater than any other value, including \"infinity\" and
    `MINVALUE` as being less than any other value, including \"minus
    infinity\". Thus the range `FROM ('infinity') TO (MAXVALUE)` is not
    an empty range; it allows precisely one value to be stored MDASH
    \"infinity\".

    If `DEFAULT` is specified, the table will be created as the default
    partition of the parent table. This option is not available for
    hash-partitioned tables. A partition key value not fitting into any
    other partition of the given parent will be routed to the default
    partition.

    When a table has an existing `DEFAULT` partition and a new partition
    is added to it, the default partition must be scanned to verify that
    it does not contain any rows which properly belong in the new
    partition. If the default partition contains a large number of rows,
    this may be slow. The scan will be skipped if the default partition
    is a foreign table or if it has a constraint which proves that it
    cannot contain rows which should be placed in the new partition.

    When creating a hash partition, a modulus and remainder must be
    specified. The modulus must be a positive integer, and the remainder
    must be a non-negative integer less than the modulus. Typically,
    when initially setting up a hash-partitioned table, you should
    choose a modulus equal to the number of partitions and assign every
    table the same modulus and a different remainder (see examples,
    below). However, it is not required that every partition have the
    same modulus, only that every modulus which occurs among the
    partitions of a hash-partitioned table is a factor of the next
    larger modulus. This allows the number of partitions to be increased
    incrementally without needing to move all the data at once. For
    example, suppose you have a hash-partitioned table with 8
    partitions, each of which has modulus 8, but find it necessary to
    increase the number of partitions to 16. You can detach one of the
    modulus-8 partitions, create two new modulus-16 partitions covering
    the same portion of the key space (one with a remainder equal to the
    remainder of the detached partition, and the other with a remainder
    equal to that value plus 8), and repopulate them with data. You can
    then repeat this \-- perhaps at a later time \-- for each modulus-8
    partition until none remain. While this may still involve a large
    amount of data movement at each step, it is still better than having
    to create a whole new table and move all the data at once.

    A partition must have the same column names and types as the
    partitioned table to which it belongs. Modifications to the column
    names or types of a partitioned table will automatically propagate
    to all partitions. `CHECK` constraints will be inherited
    automatically by every partition, but an individual partition may
    specify additional `CHECK` constraints; additional constraints with
    the same name and condition as in the parent will be merged with the
    parent constraint. Defaults may be specified separately for each
    partition. But note that a partition\'s default value is not applied
    when inserting a tuple through a partitioned table.

    Rows inserted into a partitioned table will be automatically routed
    to the correct partition. If no suitable partition exists, an error
    will occur.

    Operations such as TRUNCATE which normally affect a table and all of
    its inheritance children will cascade to all partitions, but may
    also be performed on an individual partition. Note that dropping a
    partition with `DROP TABLE` requires taking an `ACCESS
          EXCLUSIVE` lock on the parent table.

`LIKE source_table [ like_option ... ]`

:   The `LIKE` clause specifies a table from which the new table
    automatically copies all column names, their data types, and their
    not-null constraints.

    Unlike `INHERITS`, the new table and original table are completely
    decoupled after creation is complete. Changes to the original table
    will not be applied to the new table, and it is not possible to
    include data of the new table in scans of the original table.

    Also unlike `INHERITS`, columns and constraints copied by `LIKE` are
    not merged with similarly named columns and constraints. If the same
    name is specified explicitly or in another `LIKE` clause, an error
    is signaled.

    The optional like\_option clauses specify which additional
    properties of the original table to copy. Specifying `INCLUDING`
    copies the property, specifying `EXCLUDING` omits the property.
    `EXCLUDING` is the default. If multiple specifications are made for
    the same kind of object, the last one is used. The available options
    are:

    `INCLUDING COMMENTS`

    :   Comments for the copied columns, constraints, and indexes will
        be copied. The default behavior is to exclude comments,
        resulting in the copied columns and constraints in the new table
        having no comments.

    `INCLUDING COMPRESSION`

    :   Compression method of the columns will be copied. The default
        behavior is to exclude compression methods, resulting in columns
        having the default compression method.

    `INCLUDING CONSTRAINTS`

    :   `CHECK` constraints will be copied. No distinction is made
        between column constraints and table constraints. Not-null
        constraints are always copied to the new table.

    `INCLUDING DEFAULTS`

    :   Default expressions for the copied column definitions will be
        copied. Otherwise, default expressions are not copied, resulting
        in the copied columns in the new table having null defaults.
        Note that copying defaults that call database-modification
        functions, such as `nextval`, may create a functional linkage
        between the original and new tables.

    `INCLUDING GENERATED`

    :   Any generation expressions of copied column definitions will be
        copied. By default, new columns will be regular base columns.

    `INCLUDING IDENTITY`

    :   Any identity specifications of copied column definitions will be
        copied. A new sequence is created for each identity column of
        the new table, separate from the sequences associated with the
        old table.

    `INCLUDING INDEXES`

    :   Indexes, `PRIMARY KEY`, `UNIQUE`, and `EXCLUDE` constraints on
        the original table will be created on the new table. Names for
        the new indexes and constraints are chosen according to the
        default rules, regardless of how the originals were named. (This
        behavior avoids possible duplicate-name failures for the new
        indexes.)

    `INCLUDING STATISTICS`

    :   Extended statistics are copied to the new table.

    `INCLUDING STORAGE`

    :   `STORAGE` settings for the copied column definitions will be
        copied. The default behavior is to exclude `STORAGE` settings,
        resulting in the copied columns in the new table having
        type-specific default settings. For more on `STORAGE` settings,
        see [???](#storage-toast).

    `INCLUDING ALL`

    :   `INCLUDING ALL` is an abbreviated form selecting all the
        available individual options. (It could be useful to write
        individual `EXCLUDING` clauses after `INCLUDING ALL` to select
        all but some specific options.)

    The `LIKE` clause can also be used to copy column definitions from
    views, foreign tables, or composite types. Inapplicable options
    (e.g., `INCLUDING INDEXES` from a view) are ignored.

`CONSTRAINT constraint_name`

:   An optional name for a column or table constraint. If the constraint
    is violated, the constraint name is present in error messages, so
    constraint names like `col must be positive` can be used to
    communicate helpful constraint information to client applications.
    (Double-quotes are needed to specify constraint names that contain
    spaces.) If a constraint name is not specified, the system generates
    a name.

`NOT NULL`

:   The column is not allowed to contain null values.

`NULL`

:   The column is allowed to contain null values. This is the default.

    This clause is only provided for compatibility with non-standard SQL
    databases. Its use is discouraged in new applications.

`CHECK ( expression ) [ NO INHERIT ] `

:   The `CHECK` clause specifies an expression producing a Boolean
    result which new or updated rows must satisfy for an insert or
    update operation to succeed. Expressions evaluating to TRUE or
    UNKNOWN succeed. Should any row of an insert or update operation
    produce a FALSE result, an error exception is raised and the insert
    or update does not alter the database. A check constraint specified
    as a column constraint should reference that column\'s value only,
    while an expression appearing in a table constraint can reference
    multiple columns.

    Currently, `CHECK` expressions cannot contain subqueries nor refer
    to variables other than columns of the current row (see
    [???](#ddl-constraints-check-constraints)). The system column
    `tableoid` may be referenced, but not any other system column.

    A constraint marked with `NO INHERIT` will not propagate to child
    tables.

    When a table has multiple `CHECK` constraints, they will be tested
    for each row in alphabetical order by name, after checking
    `NOT NULL` constraints. (PostgreSQL versions before 9.5 did not
    honor any particular firing order for `CHECK` constraints.)

`DEFAULT
    default_expr`

:   The `DEFAULT` clause assigns a default data value for the column
    whose column definition it appears within. The value is any
    variable-free expression (in particular, cross-references to other
    columns in the current table are not allowed). Subqueries are not
    allowed either. The data type of the default expression must match
    the data type of the column.

    The default expression will be used in any insert operation that
    does not specify a value for the column. If there is no default for
    a column, then the default is null.

`GENERATED ALWAYS AS ( generation_expr ) STORED`generated column

:   This clause creates the column as a generated column. The column
    cannot be written to, and when read the result of the specified
    expression will be returned.

    The keyword `STORED` is required to signify that the column will be
    computed on write and will be stored on disk.

    The generation expression can refer to other columns in the table,
    but not other generated columns. Any functions and operators used
    must be immutable. References to other tables are not allowed.

`GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( sequence_options ) ]`

:   This clause creates the column as an identity column. It will have
    an implicit sequence attached to it and the column in new rows will
    automatically have values from the sequence assigned to it. Such a
    column is implicitly `NOT NULL`.

    The clauses `ALWAYS` and `BY DEFAULT` determine how explicitly
    user-specified values are handled in `INSERT` and `UPDATE` commands.

    In an `INSERT` command, if `ALWAYS` is selected, a user-specified
    value is only accepted if the `INSERT` statement specifies
    `OVERRIDING SYSTEM
          VALUE`. If `BY DEFAULT` is selected, then the user-specified
    value takes precedence. See [???](#sql-insert) for details. (In the
    `COPY` command, user-specified values are always used regardless of
    this setting.)

    In an `UPDATE` command, if `ALWAYS` is selected, any update of the
    column to any value other than `DEFAULT` will be rejected. If `BY
          DEFAULT` is selected, the column can be updated normally.
    (There is no `OVERRIDING` clause for the `UPDATE` command.)

    The optional sequence\_options clause can be used to override the
    options of the sequence. See [???](#sql-createsequence) for details.

`UNIQUE [ NULLS [ NOT ] DISTINCT ]` (column constraint); `UNIQUE [ NULLS [ NOT ] DISTINCT ] ( column_name [, ... ] )` \[`INCLUDE ( column_name [, ...])`\] (table constraint)

:   The `UNIQUE` constraint specifies that a group of one or more
    columns of a table can contain only unique values. The behavior of a
    unique table constraint is the same as that of a unique column
    constraint, with the additional capability to span multiple columns.
    The constraint therefore enforces that any two rows must differ in
    at least one of these columns.

    For the purpose of a unique constraint, null values are not
    considered equal, unless `NULLS NOT DISTINCT` is specified.

    Each unique constraint should name a set of columns that is
    different from the set of columns named by any other unique or
    primary key constraint defined for the table. (Otherwise, redundant
    unique constraints will be discarded.)

    When establishing a unique constraint for a multi-level partition
    hierarchy, all the columns in the partition key of the target
    partitioned table, as well as those of all its descendant
    partitioned tables, must be included in the constraint definition.

    Adding a unique constraint will automatically create a unique btree
    index on the column or group of columns used in the constraint.

    The optional `INCLUDE` clause adds to that index one or more columns
    that are simply "payload": uniqueness is not enforced on them, and
    the index cannot be searched on the basis of those columns. However
    they can be retrieved by an index-only scan. Note that although the
    constraint is not enforced on included columns, it still depends on
    them. Consequently, some operations on such columns (e.g.,
    `DROP COLUMN`) can cause cascaded constraint and index deletion.

`PRIMARY KEY` (column constraint); `PRIMARY KEY ( column_name [, ... ] )` \[`INCLUDE ( column_name [, ...])`\] (table constraint)

:   The `PRIMARY KEY` constraint specifies that a column or columns of a
    table can contain only unique (non-duplicate), nonnull values. Only
    one primary key can be specified for a table, whether as a column
    constraint or a table constraint.

    The primary key constraint should name a set of columns that is
    different from the set of columns named by any unique constraint
    defined for the same table. (Otherwise, the unique constraint is
    redundant and will be discarded.)

    `PRIMARY KEY` enforces the same data constraints as a combination of
    `UNIQUE` and `NOT
          NULL`. However, identifying a set of columns as the primary
    key also provides metadata about the design of the schema, since a
    primary key implies that other tables can rely on this set of
    columns as a unique identifier for rows.

    When placed on a partitioned table, `PRIMARY KEY` constraints share
    the restrictions previously described for `UNIQUE` constraints.

    Adding a `PRIMARY KEY` constraint will automatically create a unique
    btree index on the column or group of columns used in the
    constraint.

    The optional `INCLUDE` clause adds to that index one or more columns
    that are simply "payload": uniqueness is not enforced on them, and
    the index cannot be searched on the basis of those columns. However
    they can be retrieved by an index-only scan. Note that although the
    constraint is not enforced on included columns, it still depends on
    them. Consequently, some operations on such columns (e.g.,
    `DROP COLUMN`) can cause cascaded constraint and index deletion.

`EXCLUDE [ USING index_method ] ( exclude_element WITH operator [, ... ] ) index_parameters [ WHERE ( predicate ) ]`

:   The `EXCLUDE` clause defines an exclusion constraint, which
    guarantees that if any two rows are compared on the specified
    column(s) or expression(s) using the specified operator(s), not all
    of these comparisons will return `TRUE`. If all of the specified
    operators test for equality, this is equivalent to a `UNIQUE`
    constraint, although an ordinary unique constraint will be faster.
    However, exclusion constraints can specify constraints that are more
    general than simple equality. For example, you can specify a
    constraint that no two rows in the table contain overlapping circles
    (see [???](#datatype-geometric)) by using the `&&` operator.

    Exclusion constraints are implemented using an index, so each
    specified operator must be associated with an appropriate operator
    class (see [???](#indexes-opclass)) for the index access method
    index\_method. The operators are required to be commutative. Each
    exclude\_element can optionally specify an operator class and/or
    ordering options; these are described fully under
    [???](#sql-createindex).

    The access method must support `amgettuple` (see [???](#indexam));
    at present this means GIN cannot be used. Although it\'s allowed,
    there is little point in using B-tree or hash indexes with an
    exclusion constraint, because this does nothing that an ordinary
    unique constraint doesn\'t do better. So in practice the access
    method will always be GiST or SP-GiST.

    The predicate allows you to specify an exclusion constraint on a
    subset of the table; internally this creates a partial index. Note
    that parentheses are required around the predicate.

`REFERENCES reftable [ ( refcolumn ) ] [ MATCH matchtype ] [ ON DELETE referential_action ] [ ON UPDATE referential_action ]` (column constraint); `FOREIGN KEY ( column_name [, ... ] )
    REFERENCES reftable [ ( refcolumn [, ... ] ) ]
    [ MATCH matchtype ]
    [ ON DELETE referential_action ]
    [ ON UPDATE referential_action ]` (table constraint)

:   These clauses specify a foreign key constraint, which requires that
    a group of one or more columns of the new table must only contain
    values that match values in the referenced column(s) of some row of
    the referenced table. If the refcolumn list is omitted, the primary
    key of the reftable is used. The referenced columns must be the
    columns of a non-deferrable unique or primary key constraint in the
    referenced table. The user must have `REFERENCES` permission on the
    referenced table (either the whole table, or the specific referenced
    columns). The addition of a foreign key constraint requires a
    `SHARE ROW EXCLUSIVE` lock on the referenced table. Note that
    foreign key constraints cannot be defined between temporary tables
    and permanent tables.

    A value inserted into the referencing column(s) is matched against
    the values of the referenced table and referenced columns using the
    given match type. There are three match types: `MATCH
          FULL`, `MATCH PARTIAL`, and `MATCH
          SIMPLE` (which is the default). `MATCH
          FULL` will not allow one column of a multicolumn foreign key
    to be null unless all foreign key columns are null; if they are all
    null, the row is not required to have a match in the referenced
    table. `MATCH SIMPLE` allows any of the foreign key columns to be
    null; if any of them are null, the row is not required to have a
    match in the referenced table. `MATCH PARTIAL` is not yet
    implemented. (Of course, `NOT NULL` constraints can be applied to
    the referencing column(s) to prevent these cases from arising.)

    In addition, when the data in the referenced columns is changed,
    certain actions are performed on the data in this table\'s columns.
    The `ON DELETE` clause specifies the action to perform when a
    referenced row in the referenced table is being deleted. Likewise,
    the `ON UPDATE` clause specifies the action to perform when a
    referenced column in the referenced table is being updated to a new
    value. If the row is updated, but the referenced column is not
    actually changed, no action is done. Referential actions other than
    the `NO ACTION` check cannot be deferred, even if the constraint is
    declared deferrable. There are the following possible actions for
    each clause:

    `NO ACTION`

    :   Produce an error indicating that the deletion or update would
        create a foreign key constraint violation. If the constraint is
        deferred, this error will be produced at constraint check time
        if there still exist any referencing rows. This is the default
        action.

    `RESTRICT`

    :   Produce an error indicating that the deletion or update would
        create a foreign key constraint violation. This is the same as
        `NO ACTION` except that the check is not deferrable.

    `CASCADE`

    :   Delete any rows referencing the deleted row, or update the
        values of the referencing column(s) to the new values of the
        referenced columns, respectively.

    `SET NULL [ ( column_name [, ... ] ) ]`

    :   Set all of the referencing columns, or a specified subset of the
        referencing columns, to null. A subset of columns can only be
        specified for `ON DELETE` actions.

    `SET DEFAULT [ ( column_name [, ... ] ) ]`

    :   Set all of the referencing columns, or a specified subset of the
        referencing columns, to their default values. A subset of
        columns can only be specified for `ON DELETE` actions. (There
        must be a row in the referenced table matching the default
        values, if they are not null, or the operation will fail.)

    If the referenced column(s) are changed frequently, it might be wise
    to add an index to the referencing column(s) so that referential
    actions associated with the foreign key constraint can be performed
    more efficiently.

`DEFERRABLE`; `NOT DEFERRABLE`

:   This controls whether the constraint can be deferred. A constraint
    that is not deferrable will be checked immediately after every
    command. Checking of constraints that are deferrable can be
    postponed until the end of the transaction (using the
    [`SET CONSTRAINTS`](#sql-set-constraints) command). `NOT DEFERRABLE`
    is the default. Currently, only `UNIQUE`, `PRIMARY KEY`, `EXCLUDE`,
    and `REFERENCES` (foreign key) constraints accept this clause.
    `NOT NULL` and `CHECK` constraints are not deferrable. Note that
    deferrable constraints cannot be used as conflict arbitrators in an
    `INSERT` statement that includes an `ON CONFLICT DO UPDATE` clause.

`INITIALLY IMMEDIATE`; `INITIALLY DEFERRED`

:   If a constraint is deferrable, this clause specifies the default
    time to check the constraint. If the constraint is
    `INITIALLY IMMEDIATE`, it is checked after each statement. This is
    the default. If the constraint is `INITIALLY DEFERRED`, it is
    checked only at the end of the transaction. The constraint check
    time can be altered with the
    [`SET CONSTRAINTS`](#sql-set-constraints) command.

`USING method`

:   This optional clause specifies the table access method to use to
    store the contents for the new table; the method needs be an access
    method of type `TABLE`. See [???](#tableam) for more information. If
    this option is not specified, the default table access method is
    chosen for the new table. See
    [???](#guc-default-table-access-method) for more information.

`WITH ( storage_parameter [= value] [, ... ] )`

:   This clause specifies optional storage parameters for a table or
    index; see [Storage Parameters](#sql-createtable-storage-parameters)
    below for more information. For backward-compatibility the `WITH`
    clause for a table can also include `OIDS=FALSE` to specify that
    rows of the new table should not contain OIDs (object identifiers),
    `OIDS=TRUE` is not supported anymore.

`WITHOUT OIDS`

:   This is backward-compatible syntax for declaring a table
    `WITHOUT OIDS`, creating a table `WITH
          OIDS` is not supported anymore.

`ON COMMIT`

:   The behavior of temporary tables at the end of a transaction block
    can be controlled using `ON COMMIT`. The three options are:

    `PRESERVE ROWS`

    :   No special action is taken at the ends of transactions. This is
        the default behavior.

    `DELETE ROWS`

    :   All rows in the temporary table will be deleted at the end of
        each transaction block. Essentially, an automatic
        [`TRUNCATE`](#sql-truncate) is done at each commit. When used on
        a partitioned table, this is not cascaded to its partitions.

    `DROP`

    :   The temporary table will be dropped at the end of the current
        transaction block. When used on a partitioned table, this action
        drops its partitions and when used on tables with inheritance
        children, it drops the dependent children.

`TABLESPACE tablespace_name`

:   The tablespace\_name is the name of the tablespace in which the new
    table is to be created. If not specified,
    [???](#guc-default-tablespace) is consulted, or
    [???](#guc-temp-tablespaces) if the table is temporary. For
    partitioned tables, since no storage is required for the table
    itself, the tablespace specified overrides `default_tablespace` as
    the default tablespace to use for any newly created partitions when
    no other tablespace is explicitly specified.

`USING INDEX TABLESPACE tablespace_name`

:   This clause allows selection of the tablespace in which the index
    associated with a `UNIQUE`, `PRIMARY
          KEY`, or `EXCLUDE` constraint will be created. If not
    specified, [???](#guc-default-tablespace) is consulted, or
    [???](#guc-temp-tablespaces) if the table is temporary.

Storage Parameters {#sql-createtable-storage-parameters}
------------------

storage parameters

The `WITH` clause can specify storage parameters for tables, and for
indexes associated with a `UNIQUE`, `PRIMARY KEY`, or `EXCLUDE`
constraint. Storage parameters for indexes are documented in
[???](#sql-createindex). The storage parameters currently available for
tables are listed below. For many of these parameters, as shown, there
is an additional parameter with the same name prefixed with `toast.`,
which controls the behavior of the table\'s secondary TOAST table, if
any (see [???](#storage-toast) for more information about TOAST). If a
table parameter value is set and the equivalent `toast.` parameter is
not, the TOAST table will use the table\'s parameter value. Specifying
these parameters for partitioned tables is not supported, but you may
specify them for individual leaf partitions.

`fillfactor` (`integer`) `fillfactor` storage parameter

:   The fillfactor for a table is a percentage between 10 and 100. 100
    (complete packing) is the default. When a smaller fillfactor is
    specified, `INSERT` operations pack table pages only to the
    indicated percentage; the remaining space on each page is reserved
    for updating rows on that page. This gives `UPDATE` a chance to
    place the updated copy of a row on the same page as the original,
    which is more efficient than placing it on a different page. For a
    table whose entries are never updated, complete packing is the best
    choice, but in heavily updated tables smaller fillfactors are
    appropriate. This parameter cannot be set for TOAST tables.

`toast_tuple_target` (`integer`) `toast_tuple_target` storage parameter

:   The toast\_tuple\_target specifies the minimum tuple length required
    before we try to compress and/or move long column values into TOAST
    tables, and is also the target length we try to reduce the length
    below once toasting begins. This affects columns marked as External
    (for move), Main (for compression), or Extended (for both) and
    applies only to new tuples. There is no effect on existing rows. By
    default this parameter is set to allow at least 4 tuples per block,
    which with the default block size will be 2040 bytes. Valid values
    are between 128 bytes and the (block size - header), by default 8160
    bytes. Changing this value may not be useful for very short or very
    long rows. Note that the default setting is often close to optimal,
    and it is possible that setting this parameter could have negative
    effects in some cases. This parameter cannot be set for TOAST
    tables.

`parallel_workers` (`integer`) `parallel_workers` storage parameter

:   This sets the number of workers that should be used to assist a
    parallel scan of this table. If not set, the system will determine a
    value based on the relation size. The actual number of workers
    chosen by the planner or by utility statements that use parallel
    scans may be less, for example due to the setting of
    [???](#guc-max-worker-processes).

`autovacuum_enabled`, `toast.autovacuum_enabled` (`boolean`) `autovacuum_enabled` storage parameter

:   Enables or disables the autovacuum daemon for a particular table. If
    true, the autovacuum daemon will perform automatic `VACUUM` and/or
    `ANALYZE` operations on this table following the rules discussed in
    [???](#autovacuum). If false, this table will not be autovacuumed,
    except to prevent transaction ID wraparound. See
    [???](#vacuum-for-wraparound) for more about wraparound prevention.
    Note that the autovacuum daemon does not run at all (except to
    prevent transaction ID wraparound) if the [???](#guc-autovacuum)
    parameter is false; setting individual tables\' storage parameters
    does not override that. Therefore there is seldom much point in
    explicitly setting this storage parameter to `true`, only to
    `false`.

`vacuum_index_cleanup`, `toast.vacuum_index_cleanup` (`enum`) `vacuum_index_cleanup` storage parameter

:   Forces or disables index cleanup when `VACUUM` is run on this table.
    The default value is `AUTO`. With `OFF`, index cleanup is disabled,
    with `ON` it is enabled, and with `AUTO` a decision is made
    dynamically, each time `VACUUM` runs. The dynamic behavior allows
    `VACUUM` to avoid needlessly scanning indexes to remove very few
    dead tuples. Forcibly disabling all index cleanup can speed up
    `VACUUM` very significantly, but may also lead to severely bloated
    indexes if table modifications are frequent. The `INDEX_CLEANUP`
    parameter of [`VACUUM`](#sql-vacuum), if specified, overrides the
    value of this option.

`vacuum_truncate`, `toast.vacuum_truncate` (`boolean`) `vacuum_truncate` storage parameter

:   Enables or disables vacuum to try to truncate off any empty pages at
    the end of this table. The default value is `true`. If `true`,
    `VACUUM` and autovacuum do the truncation and the disk space for the
    truncated pages is returned to the operating system. Note that the
    truncation requires `ACCESS EXCLUSIVE` lock on the table. The
    `TRUNCATE` parameter of [`VACUUM`](#sql-vacuum), if specified,
    overrides the value of this option.

`autovacuum_vacuum_threshold`, `toast.autovacuum_vacuum_threshold` (`integer`) `autovacuum_vacuum_threshold` storage parameter

:   Per-table value for [???](#guc-autovacuum-vacuum-threshold)
    parameter.

`autovacuum_vacuum_scale_factor`, `toast.autovacuum_vacuum_scale_factor` (`floating point`) `autovacuum_vacuum_scale_factor` storage parameter

:   Per-table value for [???](#guc-autovacuum-vacuum-scale-factor)
    parameter.

`autovacuum_vacuum_insert_threshold`, `toast.autovacuum_vacuum_insert_threshold` (`integer`) `autovacuum_vacuum_insert_threshold` storage parameter

:   Per-table value for [???](#guc-autovacuum-vacuum-insert-threshold)
    parameter. The special value of -1 may be used to disable insert
    vacuums on the table.

`autovacuum_vacuum_insert_scale_factor`, `toast.autovacuum_vacuum_insert_scale_factor` (`floating point`) `autovacuum_vacuum_insert_scale_factor` storage parameter

:   Per-table value for
    [???](#guc-autovacuum-vacuum-insert-scale-factor) parameter.

`autovacuum_analyze_threshold` (`integer`) `autovacuum_analyze_threshold` storage parameter

:   Per-table value for [???](#guc-autovacuum-analyze-threshold)
    parameter.

`autovacuum_analyze_scale_factor` (`floating point`) `autovacuum_analyze_scale_factor` storage parameter

:   Per-table value for [???](#guc-autovacuum-analyze-scale-factor)
    parameter.

`autovacuum_vacuum_cost_delay`, `toast.autovacuum_vacuum_cost_delay` (`floating point`) `autovacuum_vacuum_cost_delay` storage parameter

:   Per-table value for [???](#guc-autovacuum-vacuum-cost-delay)
    parameter.

`autovacuum_vacuum_cost_limit`, `toast.autovacuum_vacuum_cost_limit` (`integer`) `autovacuum_vacuum_cost_limit` storage parameter

:   Per-table value for [???](#guc-autovacuum-vacuum-cost-limit)
    parameter.

`autovacuum_freeze_min_age`, `toast.autovacuum_freeze_min_age` (`integer`) `autovacuum_freeze_min_age` storage parameter

:   Per-table value for [???](#guc-vacuum-freeze-min-age) parameter.
    Note that autovacuum will ignore per-table
    `autovacuum_freeze_min_age` parameters that are larger than half the
    system-wide [???](#guc-autovacuum-freeze-max-age) setting.

`autovacuum_freeze_max_age`, `toast.autovacuum_freeze_max_age` (`integer`) `autovacuum_freeze_max_age` storage parameter

:   Per-table value for [???](#guc-autovacuum-freeze-max-age) parameter.
    Note that autovacuum will ignore per-table
    `autovacuum_freeze_max_age` parameters that are larger than the
    system-wide setting (it can only be set smaller).

`autovacuum_freeze_table_age`, `toast.autovacuum_freeze_table_age` (`integer`) `autovacuum_freeze_table_age` storage parameter

:   Per-table value for [???](#guc-vacuum-freeze-table-age) parameter.

`autovacuum_multixact_freeze_min_age`, `toast.autovacuum_multixact_freeze_min_age` (`integer`) `autovacuum_multixact_freeze_min_age` storage parameter

:   Per-table value for [???](#guc-vacuum-multixact-freeze-min-age)
    parameter. Note that autovacuum will ignore per-table
    `autovacuum_multixact_freeze_min_age` parameters that are larger
    than half the system-wide
    [???](#guc-autovacuum-multixact-freeze-max-age) setting.

`autovacuum_multixact_freeze_max_age`, `toast.autovacuum_multixact_freeze_max_age` (`integer`) `autovacuum_multixact_freeze_max_age` storage parameter

:   Per-table value for [???](#guc-autovacuum-multixact-freeze-max-age)
    parameter. Note that autovacuum will ignore per-table
    `autovacuum_multixact_freeze_max_age` parameters that are larger
    than the system-wide setting (it can only be set smaller).

`autovacuum_multixact_freeze_table_age`, `toast.autovacuum_multixact_freeze_table_age` (`integer`) `autovacuum_multixact_freeze_table_age` storage parameter

:   Per-table value for [???](#guc-vacuum-multixact-freeze-table-age)
    parameter.

`log_autovacuum_min_duration`, `toast.log_autovacuum_min_duration` (`integer`) `log_autovacuum_min_duration` storage parameter

:   Per-table value for [???](#guc-log-autovacuum-min-duration)
    parameter.

`user_catalog_table` (`boolean`) `user_catalog_table` storage parameter

:   Declare the table as an additional catalog table for purposes of
    logical replication. See [???](#logicaldecoding-capabilities) for
    details. This parameter cannot be set for TOAST tables.

Notes {#sql-createtable-notes}
=====

PostgreSQL automatically creates an index for each unique constraint and
primary key constraint to enforce uniqueness. Thus, it is not necessary
to create an index explicitly for primary key columns. (See
[???](#sql-createindex) for more information.)

Unique constraints and primary keys are not inherited in the current
implementation. This makes the combination of inheritance and unique
constraints rather dysfunctional.

A table cannot have more than 1600 columns. (In practice, the effective
limit is usually lower because of tuple-length constraints.)

Examples {#sql-createtable-examples}
========

Create table films and table distributors:

    CREATE TABLE films (
        code        char(5) CONSTRAINT firstkey PRIMARY KEY,
        title       varchar(40) NOT NULL,
        did         integer NOT NULL,
        date_prod   date,
        kind        varchar(10),
        len         interval hour to minute
    );

    CREATE TABLE distributors (
         did    integer PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
         name   varchar(40) NOT NULL CHECK (name <> '')
    );

Create a table with a 2-dimensional array:

    CREATE TABLE array_int (
        vector  int[][]
    );

Define a unique table constraint for the table `films`. Unique table
constraints can be defined on one or more columns of the table:

    CREATE TABLE films (
        code        char(5),
        title       varchar(40),
        did         integer,
        date_prod   date,
        kind        varchar(10),
        len         interval hour to minute,
        CONSTRAINT production UNIQUE(date_prod)
    );

Define a check column constraint:

    CREATE TABLE distributors (
        did     integer CHECK (did > 100),
        name    varchar(40)
    );

Define a check table constraint:

    CREATE TABLE distributors (
        did     integer,
        name    varchar(40),
        CONSTRAINT con1 CHECK (did > 100 AND name <> '')
    );

Define a primary key table constraint for the table films:

    CREATE TABLE films (
        code        char(5),
        title       varchar(40),
        did         integer,
        date_prod   date,
        kind        varchar(10),
        len         interval hour to minute,
        CONSTRAINT code_title PRIMARY KEY(code,title)
    );

Define a primary key constraint for table distributors. The following
two examples are equivalent, the first using the table constraint
syntax, the second the column constraint syntax:

    CREATE TABLE distributors (
        did     integer,
        name    varchar(40),
        PRIMARY KEY(did)
    );

    CREATE TABLE distributors (
        did     integer PRIMARY KEY,
        name    varchar(40)
    );

Assign a literal constant default value for the column `name`, arrange
for the default value of column `did` to be generated by selecting the
next value of a sequence object, and make the default value of `modtime`
be the time at which the row is inserted:

    CREATE TABLE distributors (
        name      varchar(40) DEFAULT 'Luso Films',
        did       integer DEFAULT nextval('distributors_serial'),
        modtime   timestamp DEFAULT current_timestamp
    );

Define two `NOT NULL` column constraints on the table `distributors`,
one of which is explicitly given a name:

    CREATE TABLE distributors (
        did     integer CONSTRAINT no_null NOT NULL,
        name    varchar(40) NOT NULL
    );

Define a unique constraint for the `name` column:

    CREATE TABLE distributors (
        did     integer,
        name    varchar(40) UNIQUE
    );

The same, specified as a table constraint:

    CREATE TABLE distributors (
        did     integer,
        name    varchar(40),
        UNIQUE(name)
    );

Create the same table, specifying 70% fill factor for both the table and
its unique index:

    CREATE TABLE distributors (
        did     integer,
        name    varchar(40),
        UNIQUE(name) WITH (fillfactor=70)
    )
    WITH (fillfactor=70);

Create table circles with an exclusion constraint that prevents any two
circles from overlapping:

    CREATE TABLE circles (
        c circle,
        EXCLUDE USING gist (c WITH &&)
    );

Create table cinemas in tablespace diskvol1:

    CREATE TABLE cinemas (
            id serial,
            name text,
            location text
    ) TABLESPACE diskvol1;

Create a composite type and a typed table:

    CREATE TYPE employee_type AS (name text, salary numeric);

    CREATE TABLE employees OF employee_type (
        PRIMARY KEY (name),
        salary WITH OPTIONS DEFAULT 1000
    );

Create a range partitioned table:

    CREATE TABLE measurement (
        logdate         date not null,
        peaktemp        int,
        unitsales       int
    ) PARTITION BY RANGE (logdate);

Create a range partitioned table with multiple columns in the partition
key:

    CREATE TABLE measurement_year_month (
        logdate         date not null,
        peaktemp        int,
        unitsales       int
    ) PARTITION BY RANGE (EXTRACT(YEAR FROM logdate), EXTRACT(MONTH FROM logdate));

Create a list partitioned table:

    CREATE TABLE cities (
        city_id      bigserial not null,
        name         text not null,
        population   bigint
    ) PARTITION BY LIST (left(lower(name), 1));

Create a hash partitioned table:

    CREATE TABLE orders (
        order_id     bigint not null,
        cust_id      bigint not null,
        status       text
    ) PARTITION BY HASH (order_id);

Create partition of a range partitioned table:

    CREATE TABLE measurement_y2016m07
        PARTITION OF measurement (
        unitsales DEFAULT 0
    ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');

Create a few partitions of a range partitioned table with multiple
columns in the partition key:

    CREATE TABLE measurement_ym_older
        PARTITION OF measurement_year_month
        FOR VALUES FROM (MINVALUE, MINVALUE) TO (2016, 11);

    CREATE TABLE measurement_ym_y2016m11
        PARTITION OF measurement_year_month
        FOR VALUES FROM (2016, 11) TO (2016, 12);

    CREATE TABLE measurement_ym_y2016m12
        PARTITION OF measurement_year_month
        FOR VALUES FROM (2016, 12) TO (2017, 01);

    CREATE TABLE measurement_ym_y2017m01
        PARTITION OF measurement_year_month
        FOR VALUES FROM (2017, 01) TO (2017, 02);

Create partition of a list partitioned table:

    CREATE TABLE cities_ab
        PARTITION OF cities (
        CONSTRAINT city_id_nonzero CHECK (city_id != 0)
    ) FOR VALUES IN ('a', 'b');

Create partition of a list partitioned table that is itself further
partitioned and then add a partition to it:

    CREATE TABLE cities_ab
        PARTITION OF cities (
        CONSTRAINT city_id_nonzero CHECK (city_id != 0)
    ) FOR VALUES IN ('a', 'b') PARTITION BY RANGE (population);

    CREATE TABLE cities_ab_10000_to_100000
        PARTITION OF cities_ab FOR VALUES FROM (10000) TO (100000);

Create partitions of a hash partitioned table:

    CREATE TABLE orders_p1 PARTITION OF orders
        FOR VALUES WITH (MODULUS 4, REMAINDER 0);
    CREATE TABLE orders_p2 PARTITION OF orders
        FOR VALUES WITH (MODULUS 4, REMAINDER 1);
    CREATE TABLE orders_p3 PARTITION OF orders
        FOR VALUES WITH (MODULUS 4, REMAINDER 2);
    CREATE TABLE orders_p4 PARTITION OF orders
        FOR VALUES WITH (MODULUS 4, REMAINDER 3);

Create a default partition:

    CREATE TABLE cities_partdef
        PARTITION OF cities DEFAULT;

Compatibility {#sql-createtable-compatibility}
=============

The `CREATE TABLE` command conforms to the SQL standard, with exceptions
listed below.

Temporary Tables
----------------

Although the syntax of `CREATE TEMPORARY TABLE` resembles that of the
SQL standard, the effect is not the same. In the standard, temporary
tables are defined just once and automatically exist (starting with
empty contents) in every session that needs them. PostgreSQL instead
requires each session to issue its own `CREATE TEMPORARY
    TABLE` command for each temporary table to be used. This allows
different sessions to use the same temporary table name for different
purposes, whereas the standard\'s approach constrains all instances of a
given temporary table name to have the same table structure.

The standard\'s definition of the behavior of temporary tables is widely
ignored. PostgreSQL\'s behavior on this point is similar to that of
several other SQL databases.

The SQL standard also distinguishes between global and local temporary
tables, where a local temporary table has a separate set of contents for
each SQL module within each session, though its definition is still
shared across sessions. Since PostgreSQL does not support SQL modules,
this distinction is not relevant in PostgreSQL.

For compatibility\'s sake, PostgreSQL will accept the `GLOBAL` and
`LOCAL` keywords in a temporary table declaration, but they currently
have no effect. Use of these keywords is discouraged, since future
versions of PostgreSQL might adopt a more standard-compliant
interpretation of their meaning.

The `ON COMMIT` clause for temporary tables also resembles the SQL
standard, but has some differences. If the `ON COMMIT` clause is
omitted, SQL specifies that the default behavior is
`ON COMMIT DELETE ROWS`. However, the default behavior in PostgreSQL is
`ON COMMIT PRESERVE ROWS`. The `ON COMMIT
    DROP` option does not exist in SQL.

Non-Deferred Uniqueness Constraints
-----------------------------------

When a `UNIQUE` or `PRIMARY KEY` constraint is not deferrable,
PostgreSQL checks for uniqueness immediately whenever a row is inserted
or modified. The SQL standard says that uniqueness should be enforced
only at the end of the statement; this makes a difference when, for
example, a single command updates multiple key values. To obtain
standard-compliant behavior, declare the constraint as `DEFERRABLE` but
not deferred (i.e., `INITIALLY
    IMMEDIATE`). Be aware that this can be significantly slower than
immediate uniqueness checking.

Column Check Constraints
------------------------

The SQL standard says that `CHECK` column constraints can only refer to
the column they apply to; only `CHECK` table constraints can refer to
multiple columns. PostgreSQL does not enforce this restriction; it
treats column and table check constraints alike.

`EXCLUDE` Constraint
--------------------

The `EXCLUDE` constraint type is a PostgreSQL extension.

Foreign-Key Constraint Actions
------------------------------

The ability to specify column lists in the foreign-key actions
`SET DEFAULT` and `SET NULL` is a PostgreSQL extension.

`NULL` "Constraint"
-------------------

The `NULL` "constraint" (actually a non-constraint) is a PostgreSQL
extension to the SQL standard that is included for compatibility with
some other database systems (and for symmetry with the `NOT
    NULL` constraint). Since it is the default for any column, its
presence is simply noise.

Constraint Naming
-----------------

The SQL standard says that table and domain constraints must have names
that are unique across the schema containing the table or domain.
PostgreSQL is laxer: it only requires constraint names to be unique
across the constraints attached to a particular table or domain.
However, this extra freedom does not exist for index-based constraints
(`UNIQUE`, `PRIMARY KEY`, and `EXCLUDE` constraints), because the
associated index is named the same as the constraint, and index names
must be unique across all relations within the same schema.

Currently, PostgreSQL does not record names for `NOT NULL` constraints
at all, so they are not subject to the uniqueness restriction. This
might change in a future release.

Inheritance
-----------

Multiple inheritance via the `INHERITS` clause is a PostgreSQL language
extension. SQL:1999 and later define single inheritance using a
different syntax and different semantics. SQL:1999-style inheritance is
not yet supported by PostgreSQL.

Zero-Column Tables
------------------

PostgreSQL allows a table of no columns to be created (for example,
`CREATE TABLE foo();`). This is an extension from the SQL standard,
which does not allow zero-column tables. Zero-column tables are not in
themselves very useful, but disallowing them creates odd special cases
for `ALTER TABLE
    DROP COLUMN`, so it seems cleaner to ignore this spec restriction.

Multiple Identity Columns
-------------------------

PostgreSQL allows a table to have more than one identity column. The
standard specifies that a table can have at most one identity column.
This is relaxed mainly to give more flexibility for doing schema changes
or migrations. Note that the `INSERT` command supports only one override
clause that applies to the entire statement, so having multiple identity
columns with different behaviors is not well supported.

Generated Columns
-----------------

The option `STORED` is not standard but is also used by other SQL
implementations. The SQL standard does not specify the storage of
generated columns.

`LIKE` Clause
-------------

While a `LIKE` clause exists in the SQL standard, many of the options
that PostgreSQL accepts for it are not in the standard, and some of the
standard\'s options are not implemented by PostgreSQL.

`WITH` Clause
-------------

The `WITH` clause is a PostgreSQL extension; storage parameters are not
in the standard.

Tablespaces
-----------

The PostgreSQL concept of tablespaces is not part of the standard.
Hence, the clauses `TABLESPACE` and `USING INDEX TABLESPACE` are
extensions.

Typed Tables
------------

Typed tables implement a subset of the SQL standard. According to the
standard, a typed table has columns corresponding to the underlying
composite type as well as one other column that is the "self-referencing
column". PostgreSQL does not support self-referencing columns
explicitly.

`PARTITION BY` Clause
---------------------

The `PARTITION BY` clause is a PostgreSQL extension.

`PARTITION OF` Clause
---------------------

The `PARTITION OF` clause is a PostgreSQL extension.

See Also
========
