create_table(7)

NAME#

CREATE_TABLE - define a new table

SYNOPSIS#

CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] \ntable_name\n ( [
\n
  { \ncolumn_name\n \ndata_type\n [ STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN | DEFAULT } ] [ COMPRESSION \ncompression_method\n ] [ COLLATE \ncollation\n ] [ \ncolumn_constraint\n [ ... ] ]
\n
    | \ntable_constraint\n
\n
    | LIKE \nsource_table\n [ \nlike_option\n ... ] }
\n
    [, ... ]
] )
[ INHERITS ( \nparent_table\n [, ... ] ) ]
[ PARTITION BY { RANGE | LIST | HASH } ( { \ncolumn_name\n | ( \nexpression\n ) } [ COLLATE \ncollation\n ] [ \nopclass\n ] [, ... ] ) ]
[ USING \nmethod\n ]
[ WITH ( \nstorage_parameter\n [= \nvalue\n] [, ... ] ) | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE \ntablespace_name\n ]
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] \ntable_name\n
\n
    OF \ntype_name\n [ (
\n
  { \ncolumn_name\n [ WITH OPTIONS ] [ \ncolumn_constraint\n [ ... ] ]
\n
    | \ntable_constraint\n }
\n
    [, ... ]
) ]
[ PARTITION BY { RANGE | LIST | HASH } ( { \ncolumn_name\n | ( \nexpression\n ) } [ COLLATE \ncollation\n ] [ \nopclass\n ] [, ... ] ) ]
[ USING \nmethod\n ]
[ WITH ( \nstorage_parameter\n [= \nvalue\n] [, ... ] ) | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE \ntablespace_name\n ]
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] \ntable_name\n
\n
    PARTITION OF \nparent_table\n [ (
\n
  { \ncolumn_name\n [ WITH OPTIONS ] [ \ncolumn_constraint\n [ ... ] ]
\n
    | \ntable_constraint\n }
\n
    [, ... ]
) ] { FOR VALUES \npartition_bound_spec\n | DEFAULT }
[ PARTITION BY { RANGE | LIST | HASH } ( { \ncolumn_name\n | ( \nexpression\n ) } [ COLLATE \ncollation\n ] [ \nopclass\n ] [, ... ] ) ]
[ USING \nmethod\n ]
[ WITH ( \nstorage_parameter\n [= \nvalue\n] [, ... ] ) | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE \ntablespace_name\n ]
where \ncolumn_constraint\n is:
[ CONSTRAINT \nconstraint_name\n ]
{ NOT NULL |
\n
  NULL |
\n
  CHECK ( \nexpression\n ) [ NO INHERIT ] |
\n
  DEFAULT \ndefault_expr\n |
\n
  GENERATED ALWAYS AS ( \ngeneration_expr\n ) STORED |
\n
  GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( \nsequence_options\n ) ] |
\n
  UNIQUE [ NULLS [ NOT ] DISTINCT ] \nindex_parameters\n |
\n
  PRIMARY KEY \nindex_parameters\n |
\n
  REFERENCES \nreftable\n [ ( \nrefcolumn\n ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
\n
    [ ON DELETE \nreferential_action\n ] [ ON UPDATE \nreferential_action\n ] }
[ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
and \ntable_constraint\n is:
[ CONSTRAINT \nconstraint_name\n ]
{ CHECK ( \nexpression\n ) [ NO INHERIT ] |
\n
  UNIQUE [ NULLS [ NOT ] DISTINCT ] ( \ncolumn_name\n [, ... ] ) \nindex_parameters\n |
\n
  PRIMARY KEY ( \ncolumn_name\n [, ... ] ) \nindex_parameters\n |
\n
  EXCLUDE [ USING \nindex_method\n ] ( \nexclude_element\n WITH \noperator\n [, ... ] ) \nindex_parameters\n [ WHERE ( \npredicate\n ) ] |
\n
  FOREIGN KEY ( \ncolumn_name\n [, ... ] ) REFERENCES \nreftable\n [ ( \nrefcolumn\n [, ... ] ) ]
\n
    [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE \nreferential_action\n ] [ ON UPDATE \nreferential_action\n ] }
[ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
and \nlike_option\n is:
{ INCLUDING | EXCLUDING } { COMMENTS | COMPRESSION | CONSTRAINTS | DEFAULTS | GENERATED | IDENTITY | INDEXES | STATISTICS | STORAGE | ALL }
and \npartition_bound_spec\n is:
IN ( \npartition_bound_expr\n [, ...] ) |
FROM ( { \npartition_bound_expr\n | MINVALUE | MAXVALUE } [, ...] )
\n
  TO ( { \npartition_bound_expr\n | MINVALUE | MAXVALUE } [, ...] ) |
WITH ( MODULUS \nnumeric_literal\n, REMAINDER \nnumeric_literal\n )
\nindex_parameters\n in UNIQUE, PRIMARY KEY, and EXCLUDE constraints are:
[ INCLUDE ( \ncolumn_name\n [, ... ] ) ]
[ WITH ( \nstorage_parameter\n [= \nvalue\n] [, ... ] ) ]
[ USING INDEX TABLESPACE \ntablespace_name\n ]
\nexclude_element\n in an EXCLUDE constraint is:
{ \ncolumn_name\n | ( \nexpression\n ) } [ COLLATE \ncollation\n ] [ \nopclass\n [ ( \nopclass_parameter\n = \nvalue\n [, ... ] ) ] ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ]
\nreferential_action\n in a FOREIGN KEY/REFERENCES constraint is:
{ NO ACTION | RESTRICT | CASCADE | SET NULL [ ( \ncolumn_name\n [, ... ] ) ] | SET DEFAULT [ ( \ncolumn_name\n [, ... ] ) ] }

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

The autovacuum daemon 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 below.

UNLOGGED

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

table_name

OF type_name

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

data_type

COLLATE collation

STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN | DEFAULT }

COMPRESSION compression_method

INHERITS ( parent_table [, ... ] )

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 ] [, ...] )

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 Section 36.16.3 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.

See Section 5.12 for more discussion on table partitioning.

PARTITION OF parent_table { FOR VALUES partition_bound_spec | DEFAULT }

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 (Section 9.25.5). 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 — "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 creating a partition using PARTITION OF requires taking an ACCESS EXCLUSIVE lock on the parent partitioned table. Likewise, dropping a partition with DROP TABLE requires taking an ACCESS EXCLUSIVE lock on the parent table. It is possible to use ALTER TABLE ATTACH/DETACH PARTITION to perform these operations with a weaker lock, thus reducing interference with concurrent operations on the partitioned table.

LIKE source_table [ like_option ... ]

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

INCLUDING COMPRESSION

INCLUDING CONSTRAINTS

INCLUDING DEFAULTS

INCLUDING GENERATED

INCLUDING IDENTITY

INCLUDING INDEXES

INCLUDING STATISTICS

INCLUDING STORAGE

INCLUDING ALL

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

NOT NULL

NULL

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

CHECK ( expression ) [ NO INHERIT ]

Currently, CHECK expressions cannot contain subqueries nor refer to variables other than columns of the current row (see Section 5.5.1). 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 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

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 ) ]

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 INSERT(7) 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 parameters of the sequence. The available options include those shown for CREATE SEQUENCE (CREATE_SEQUENCE(7)), plus SEQUENCE NAME name, LOGGED, and UNLOGGED, which allow selection of the name and persistence level of the sequence. Without SEQUENCE NAME, the system chooses an unused name for the sequence. Without LOGGED or UNLOGGED, the sequence will have the same persistence level as the table.

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

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 created index has the same name as the unique 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 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. That index has the same name as the primary key 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 ) ]

Exclusion constraints are implemented using an index that has the same name as the constraint, so each specified operator must be associated with an appropriate operator class (see Section 11.10) for the index access method index_method. Each exclude_element defines a column of the index, so it can optionally specify a collation, an operator class, operator class parameters, and/or ordering options; these are described fully under CREATE INDEX (CREATE_INDEX(7)).

The access method must support amgettuple (see Chapter 62); 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.

When establishing an exclusion 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. Additionally, those columns must be compared using the equality operator. These restrictions ensure that potentially-conflicting rows will exist in the same partition. The constraint may also refer to other columns which are not a part of any partition key, which can be compared using any appropriate operator.

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)

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

RESTRICT

CASCADE

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

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

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

INITIALLY IMMEDIATE INITIALLY DEFERRED

USING method

When creating a partition, the table access method is the access method of its partitioned table, if set.

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

WITHOUT OIDS

ON COMMIT

PRESERVE ROWS

DELETE ROWS

DROP

TABLESPACE tablespace_name

USING INDEX TABLESPACE tablespace_name

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 CREATE INDEX (CREATE_INDEX(7)). 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 Section 65.2 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)

toast_tuple_target (integer)

parallel_workers (integer)

autovacuum_enabled, toast.autovacuum_enabled (boolean)

vacuum_index_cleanup, toast.vacuum_index_cleanup (enum)

vacuum_truncate, toast.vacuum_truncate (boolean)

autovacuum_vacuum_threshold, toast.autovacuum_vacuum_threshold (integer)

autovacuum_vacuum_scale_factor, toast.autovacuum_vacuum_scale_factor (floating point)

autovacuum_vacuum_insert_threshold, toast.autovacuum_vacuum_insert_threshold (integer)

autovacuum_vacuum_insert_scale_factor, toast.autovacuum_vacuum_insert_scale_factor (floating point)

autovacuum_analyze_threshold (integer)

autovacuum_analyze_scale_factor (floating point)

autovacuum_vacuum_cost_delay, toast.autovacuum_vacuum_cost_delay (floating point)

autovacuum_vacuum_cost_limit, toast.autovacuum_vacuum_cost_limit (integer)

autovacuum_freeze_min_age, toast.autovacuum_freeze_min_age (integer)

autovacuum_freeze_max_age, toast.autovacuum_freeze_max_age (integer)

autovacuum_freeze_table_age, toast.autovacuum_freeze_table_age (integer)

autovacuum_multixact_freeze_min_age, toast.autovacuum_multixact_freeze_min_age (integer)

autovacuum_multixact_freeze_max_age, toast.autovacuum_multixact_freeze_max_age (integer)

autovacuum_multixact_freeze_table_age, toast.autovacuum_multixact_freeze_table_age (integer)

log_autovacuum_min_duration, toast.log_autovacuum_min_duration (integer)

user_catalog_table (boolean)

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 CREATE INDEX (CREATE_INDEX(7)) 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#

Create table films and table distributors:

CREATE TABLE films (
\n
    code        char(5) CONSTRAINT firstkey PRIMARY KEY,
\n
    title       varchar(40) NOT NULL,
\n
    did         integer NOT NULL,
\n
    date_prod   date,
\n
    kind        varchar(10),
\n
    len         interval hour to minute
);
CREATE TABLE distributors (
\n
     did    integer PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
\n
     name   varchar(40) NOT NULL CHECK (name <> '')
);

Create a table with a 2-dimensional array:

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

Define a check column constraint:

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

Define a check table constraint:

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

Define a primary key table constraint for the table films:

CREATE TABLE films (
\n
    code        char(5),
\n
    title       varchar(40),
\n
    did         integer,
\n
    date_prod   date,
\n
    kind        varchar(10),
\n
    len         interval hour to minute,
\n
    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 (
\n
    did     integer,
\n
    name    varchar(40),
\n
    PRIMARY KEY(did)
);
CREATE TABLE distributors (
\n
    did     integer PRIMARY KEY,
\n
    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 (
\n
    name      varchar(40) DEFAULT 'Luso Films',
\n
    did       integer DEFAULT nextval('distributors_serial'),
\n
    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 (
\n
    did     integer CONSTRAINT no_null NOT NULL,
\n
    name    varchar(40) NOT NULL
);

Define a unique constraint for the name column:

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

The same, specified as a table constraint:

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

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

CREATE TABLE distributors (
\n
    did     integer,
\n
    name    varchar(40),
\n
    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 (
\n
    c circle,
\n
    EXCLUDE USING gist (c WITH &&)
);

Create table cinemas in tablespace diskvol1:

CREATE TABLE cinemas (
\n
        id serial,
\n
        name text,
\n
        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 (
\n
    PRIMARY KEY (name),
\n
    salary WITH OPTIONS DEFAULT 1000
);

Create a range partitioned table:

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

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

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

Create a list partitioned table:

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

Create a hash partitioned table:

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

Create partition of a range partitioned table:

CREATE TABLE measurement_y2016m07
\n
    PARTITION OF measurement (
\n
    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
\n
    PARTITION OF measurement_year_month
\n
    FOR VALUES FROM (MINVALUE, MINVALUE) TO (2016, 11);
CREATE TABLE measurement_ym_y2016m11
\n
    PARTITION OF measurement_year_month
\n
    FOR VALUES FROM (2016, 11) TO (2016, 12);
CREATE TABLE measurement_ym_y2016m12
\n
    PARTITION OF measurement_year_month
\n
    FOR VALUES FROM (2016, 12) TO (2017, 01);
CREATE TABLE measurement_ym_y2017m01
\n
    PARTITION OF measurement_year_month
\n
    FOR VALUES FROM (2017, 01) TO (2017, 02);

Create partition of a list partitioned table:

CREATE TABLE cities_ab
\n
    PARTITION OF cities (
\n
    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
\n
    PARTITION OF cities (
\n
    CONSTRAINT city_id_nonzero CHECK (city_id != 0)
) FOR VALUES IN ('a', 'b') PARTITION BY RANGE (population);
CREATE TABLE cities_ab_10000_to_100000
\n
    PARTITION OF cities_ab FOR VALUES FROM (10000) TO (100000);

Create partitions of a hash partitioned table:

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

Create a default partition:

CREATE TABLE cities_partdef
\n
    PARTITION OF cities DEFAULT;

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 Constraints#

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

It is a PostgreSQL extension that a foreign key constraint may reference columns of a unique index instead of columns of a primary key or unique constraint.

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#

ALTER TABLE (ALTER_TABLE(7)), DROP TABLE (DROP_TABLE(7)), CREATE TABLE AS (CREATE_TABLE_AS(7)), CREATE TABLESPACE (CREATE_TABLESPACE(7)), CREATE TYPE (CREATE_TYPE(7))