diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml index f5ac58705b..5907a64a6b 100644 --- a/doc/src/sgml/ref/alter_table.sgml +++ b/doc/src/sgml/ref/alter_table.sgml @@ -1,5 +1,5 @@ @@ -161,15 +161,14 @@ ALTER TABLE table ALTER TABLE changes the definition of an existing table. The ADD COLUMN form adds a new column to the table - using the same syntax as . + using the same syntax as . The ALTER COLUMN SET/DROP DEFAULT forms allow you to set or remove the default for the column. Note that defaults only apply to subsequent INSERT commands; they do not cause rows already in the table to change. The ALTER COLUMN SET STATISTICS form allows you to set the statistics-gathering target for subsequent - operations. + operations. The RENAME clause causes the name of a table or column to change without changing any of the data contained in the affected table. Thus, the table or column will @@ -177,7 +176,7 @@ ALTER TABLE table executed. The ADD table constraint definition clause adds a new constraint to the table using the same syntax as . + linkend="SQL-CREATETABLE">. The DROP CONSTRAINT constraint clause drops all CHECK constraints on the table (and its children) that match constraint. The OWNER clause changes the owner of the table to the user @@ -205,18 +204,17 @@ ALTER TABLE table You can use the SET DEFAULT form of ALTER TABLE to set the default later. (You may also want to update the already existing rows to the - new default value, using .) + new default value, using .) Currently only CHECK constraints can be dropped from a table. The RESTRICT keyword is required, although dependencies are not checked. The CASCADE option is unsupported. To remove a PRIMARY or UNIQUE constraint, drop the - relevant index using the command. + relevant index using the command. To remove FOREIGN KEY constraints you need to recreate and reload the table, using other parameters to the - + command. diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml index 49bb05ea13..8607f895df 100644 --- a/doc/src/sgml/ref/create_table.sgml +++ b/doc/src/sgml/ref/create_table.sgml @@ -1,1976 +1,822 @@ - - CREATE TABLE - + CREATE TABLE SQL - Language Statements + - - CREATE TABLE - - - define a new table - + CREATE TABLE + define a new table + - - 2001-01-11 - - -CREATE [ TEMPORARY | TEMP ] TABLE table_name ( - { column_name type [ column_constraint [ ... ] ] - | table_constraint } [, ... ] ) - [ INHERITS ( parent_table [, ... ] ) ] - [ WITH OIDS | WITHOUT OIDS ] + +CREATE [ [ LOCAL ] { TEMPORARY | TEMP } ] TABLE table_name ( + { column_name data_type [ DEFAULT default_expr ] [ column_constraint [, ... ] ] + | table_constraint } [, ... ] +) +[ INHERITS ( parent_table [, ... ] ) ] +[ WITH OIDS | WITHOUT OIDS ] + +where column_constraint is: -where column_constraint can be: [ CONSTRAINT constraint_name ] -{ NOT NULL | NULL | UNIQUE | PRIMARY KEY | DEFAULT value | CHECK (condition) | - REFERENCES table [ ( column ) ] [ MATCH FULL | MATCH PARTIAL ] - [ ON DELETE action ] [ ON UPDATE action ] - [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ] -} +{ NOT NULL | NULL | UNIQUE | PRIMARY KEY | + CHECK (expression) | + REFERENCES reftable [ ( refcolumn ) ] [ MATCH FULL | MATCH PARTIAL ] + [ ON DELETE action ] [ ON UPDATE action ] } +[ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ] + +and table_constraint is: -and table_constraint can be: [ CONSTRAINT constraint_name ] { UNIQUE ( column_name [, ... ] ) | PRIMARY KEY ( column_name [, ... ] ) | - CHECK ( condition ) | - FOREIGN KEY ( column_name [, ... ] ) REFERENCES table [ ( column [, ... ] ) ] - [ MATCH FULL | MATCH PARTIAL ] [ ON DELETE action ] [ ON UPDATE action ] - [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ] -} - + CHECK ( expression ) | + FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ] + [ MATCH FULL | MATCH PARTIAL ] [ ON DELETE action ] [ ON UPDATE action ] } +[ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ] + - - - Inputs - - - - - - - TEMPORARY or TEMP - - - If specified, the table is created only for this session, and is - automatically dropped on session exit. - Existing permanent tables with the same name are not visible - (in this session) while the temporary table exists. - Any indexes created on a temporary table are automatically - temporary as well. - - - - - - table_name - - - The name of the new table to be created. - - - - - - column_name - - - The name of a column to be created in the new table. - - - - - - type - - - The type of the column. This may include array specifiers. - Refer to the PostgreSQL User's Guide for - further information about data types and arrays. - - - - - - parent_table - - - The optional INHERITS clause specifies a list of table - names from which this table automatically inherits all fields. - - - - - - WITH OIDS or WITHOUT OIDS - - - This optional clause specifies whether rows of the new table should - have OIDs (object identifiers) assigned to them. The default is - WITH OIDS. (If the new table inherits from any tables that have OIDs, - then WITH OIDS is forced even if the command says WITHOUT OIDS.) - - - - - - constraint_name - - - An optional name for a column or table constraint. If not specified, - the system generates a name. - - - - - - value - - - A default value for a column. - See the DEFAULT clause for more information. - - - - - - condition - - - CHECK clauses specify integrity constraints or tests which new or - updated rows must satisfy for an insert or update operation to - succeed. Each constraint must be an expression producing - a boolean result. - A condition appearing within a column definition should reference - that column's value only, while a condition appearing as a table - constraint may reference multiple columns. - - - - - - table - - - The name of an existing table to be referenced by a foreign - key constraint. - - - - - - column - - - The name of a column in an existing table to be referenced by a - foreign key constraint. If not specified, the primary key of - the existing table is assumed. - - - - - - action - - - A keyword indicating the action to take when a foreign key - constraint is violated. - - - - - - - - - - Outputs - - - - - - -CREATE - - - - Message returned if table is successfully created. - - - - - - -ERROR - - - - Message returned if table creation failed. - This is usually accompanied by some descriptive text, such as: - -ERROR: Relation 'table' already exists - - , which occurs at runtime if the table specified already exists - in the database. - - - - - - - - - Description - + + Description - CREATE TABLE will enter a new, initially empty table - into the current database. The table will be owned by the user issuing the + CREATE TABLE will create a new, initially empty table + in the current database. The table will be owned by the user issuing the command. - Each type - may be a simple type, a complex type (set) or an array type. - Each attribute may be specified to be non-null and - each may have a default value, specified by the - . + CREATE TABLE also automatically creates a data + type that represents the tuple type (structure type) corresponding + to one row of the table. Therefore, tables cannot have the same + name as any existing data type. - - - Consistent array dimensions within an - attribute are not enforced. This will likely change in a future - release. - - + A table cannot have more than 1600 columns. (In practice, the + effective limit is lower because of tuple-length constraints). A + table cannot have the same name as a system catalog table. - CREATE TABLE also automatically creates a data type - that represents the tuple type (structure type) corresponding to one - row of the table. Therefore, tables can't have the same name as any - existing datatype. + The optional constraint clauses specify constraints (or tests) that + new or updated rows must satisfy for an insert or update operation + to succeed. A constraint is a named rule: an SQL object which + helps define valid sets of values by putting limits on the results + of insert, update, or delete operations performed on a table. - A table can have no more than 1600 columns (in practice, the - effective limit is lower because of tuple-length constraints). - A table cannot have the same name as a system catalog table. + 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 if the + constraint only affects one column. - - - INHERITS Clause - - - -INHERITS ( parent_table [, ... ] ) - - + + Parameters - - The optional INHERITS - clause specifies a list of table names from which the new table - automatically inherits all fields. If the same field name appears in - more than one parent table, Postgres reports an error unless the field - definitions match in each of the parent tables. If there is no - definition conflict, then the duplicate fields are merged to form a single - field of the new table. If the new table's own field list contains a - field name that is also inherited, this declaration must likewise match - the inherited field(s), and the field definitions are merged into one. - + - - Inherited and new field declarations of the same name must specify exactly - the same data type to avoid an error. They need not specify identical - constraints --- all constraints provided from any declaration are merged - together and all are applied to the new table. If the new table explicitly - specifies a default value for the field, this default overrides any - defaults from inherited declarations of the field. Otherwise, any parents - that specify default values for the field must all specify the same - default, or an error will be reported. - - - - Postgres automatically allows the created table to inherit functions on - tables above it in the inheritance hierarchy; that is, if we create table - foo inheriting from bar, then - functions that accept the tuple type bar can also be - applied to instances of foo. (Currently, this works - reliably for functions on the first or only parent table, but not so well - for functions on additional parents.) - - - - - - OIDS Clause - - - - WITH OIDS | WITHOUT OIDS - - - - - This clause controls whether an OID (object ID) is generated and assigned - to each row inserted into the table. The default is WITH OIDS. - Specifying WITHOUT OIDS allows the user to suppress generation of - OIDs for rows of a table. This may be worthwhile for large - tables, since it will reduce OID consumption and thereby postpone - wraparound of the 32-bit OID counter. Once the counter wraps around, - uniqueness of OIDs can no longer be assumed, which considerably reduces - their usefulness. - - - - Whenever an application makes use of OIDs to identify specific rows of - a table, it is recommended that you create a unique index on OID for - that table, to ensure that OIDs in the table will indeed uniquely - identify rows even after counter wraparound. (An index on OID is needed - anyway for fast lookup of rows by OID.) Avoid assuming that OIDs are - unique across tables --- if you need a database-wide unique identifier, - use the combination of tableoid and row OID for the purpose. (It is - likely that future Postgres releases will use a separate OID counter - for each table, so that it will be necessary not optional - to include tableoid to have a unique identifier database-wide.) - - - - - WITHOUT OIDS is not recommended for tables with no primary key, since - without either an OID or a unique data key, it is difficult to identify - specific rows. - - - - - - - DEFAULT Clause - - - -DEFAULT value - - - - - The DEFAULT clause assigns a default data value for the column whose - column definition it appears within. The value is any variable-free - expression (note that sub-selects and cross-references to other - columns in the current table are not supported). - The data type of a default value must match the column definition's - data type. - - - - The DEFAULT expression will be used in any INSERT operation that does - not specify a value for the column. If there is no DEFAULT clause, - then the default is NULL. - - - - - Usage - - - - -CREATE TABLE distributors ( - name VARCHAR(40) DEFAULT 'luso films', - did INTEGER DEFAULT NEXTVAL('distributors_serial'), - modtime TIMESTAMP DEFAULT now() -); - - The above assigns a literal constant default value for the column - name, and arranges for the default value of column - did to be generated by selecting the next value of a - sequence object. The default value of modtime will - be the time at which the row is inserted. - - - - It is worth remarking that - - modtime TIMESTAMP DEFAULT 'now' - - would produce a result that is probably not the intended one: the - string 'now' will be coerced to a timestamp value - immediately, and so the default value of modtime will - always be the time of table creation. This difficulty is avoided by - specifying the default value as a function call. - - - - - - - Column Constraints - - - -[ CONSTRAINT constraint_name ] { - NULL | NOT NULL | UNIQUE | PRIMARY KEY | CHECK condition | - REFERENCES reftable [ ( refcolumn ) ] - [ MATCH matchtype ] - [ ON DELETE action ] - [ ON UPDATE action ] - [ [ NOT ] DEFERRABLE ] - [ INITIALLY checktime ] } - - - - - - Inputs - - - - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - - NULL - - - The column is allowed to contain NULL values. This is the default. - - - - - - NOT NULL - - - The column is not allowed to contain NULL values. - This is equivalent to the column constraint - CHECK (column NOT NULL). - - - - - - UNIQUE - - - The column must have unique values. In Postgres - this is enforced by automatic creation of a unique index on the column. - - - - - - PRIMARY KEY - - - This column is a primary key, which implies that other tables may rely - on this column as a unique identifier for rows. Both UNIQUE and - NOT NULL are implied by PRIMARY KEY. See PRIMARY KEY for more - information. - - - - - - -condition - - - - An arbitrary boolean-valued constraint condition. - - - - - - - - - - Description - - - - The optional constraint clauses specify constraints or tests which - new or updated rows must satisfy for an insert or update - operation to succeed. - - - - A constraint is a named rule: an SQL object which helps define - valid sets of values by putting limits on the results of INSERT, - UPDATE or DELETE operations performed on a table. - - - - There are two ways to define integrity constraints: - table constraints, covered later, and column constraints, covered here. - - - - A column constraint is an integrity constraint defined as part of a - column definition, and logically becomes a table constraint as soon - as it is created. The column constraints available are: - - - PRIMARY KEY - REFERENCES - UNIQUE - CHECK - NOT NULL - - - - - - - NOT NULL Constraint - - -[ CONSTRAINT name ] NOT NULL - - - The NOT NULL constraint specifies a rule that a column may - contain only non-null values. - This is a column constraint only, and not allowed - as a table constraint. - - - - - Outputs - - - - - status - - - - - -ERROR: ExecAppend: Fail to add null value in not null attribute "column". - - - - This error occurs at runtime if one tries to insert a null value - into a column which has a NOT NULL constraint. - - - - - - - - - - - - - - Description - - - - - - - - Usage - - - - Define two NOT NULL column constraints on the table - distributors, - one of which is explicitly given a name: - - -CREATE TABLE distributors ( - did DECIMAL(3) CONSTRAINT no_null NOT NULL, - name VARCHAR(40) NOT NULL -); - - - - - - - - UNIQUE Constraint - - -[ CONSTRAINT constraint_name ] UNIQUE - - - - Inputs - - - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - - - - - Outputs - - - - status - - - - - -ERROR: Cannot insert a duplicate key into a unique index. - - - - This error occurs at runtime if one tries to insert a - duplicate value into a column. - - - - - - - - - - - - - - Description - - - - The UNIQUE constraint specifies a rule that a group of one or - more distinct columns of a table may contain only unique values. - - - The column definitions of the specified columns do not have to - include a NOT NULL constraint to be included in a UNIQUE - constraint. Having more than one null value in a column without a - NOT NULL constraint, does not violate a UNIQUE constraint. (This - deviates from the SQL92 definition, but is a - more sensible convention. See the section on compatibility for more - details.) - - - Each UNIQUE column constraint must name a column that is - different from the set of columns named by any other UNIQUE or - PRIMARY KEY constraint defined for the table. - - + + [LOCAL] TEMPORARY or [LOCAL] TEMP + - Postgres automatically creates a unique - index for each UNIQUE constraint, to assure - data integrity. See CREATE INDEX for more information. + If specified, the table is created as a temporary table. + Temporary tables are automatically dropped at the end of a + session. Existing persistent tables with the same name are not + visible to the current session while the temporary table exists. + Any indexes created on a temporary table are automatically + temporary as well. - - - - - Usage - + + The LOCAL word is optional. But see under + . + + + - - Defines a UNIQUE constraint for the name column: - -CREATE TABLE distributors ( - did DECIMAL(3), - name VARCHAR(40) UNIQUE -); - + + table_name + + + The name of the table to be created. + + + - which is equivalent to the following specified as a table constraint: - -CREATE TABLE distributors ( - did DECIMAL(3), - name VARCHAR(40), - UNIQUE(name) -); - - - - + + column_name + + + The name of a column to be created in the new table. + + + - - - The CHECK Constraint - - -[ CONSTRAINT constraint_name ] CHECK ( condition ) - - - Inputs - + + data_type + + + The data type of the column. This may include array specifiers. + Refer to the User's Guide for further + information about data types and arrays. + + + - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - condition - - - Any valid conditional expression evaluating to a boolean result. - - - - - - + + 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 (subselects and cross-references + to other columns in the current table are not allowed). The + data type of the default expression must match the data type of the + column. + - - - Outputs - - + + 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. + + + - - - status - - + + INHERITS ( parent_table [, ... ] ) + + + The optional INHERITS clause specifies a list of + tables from which the new table automatically inherits all + columns. 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 that is also inherited, the data type must + likewise match the inherited column(s), and the column + definitions are merged into one. However, inherited and new + column declarations of the same name need not specify identical + constraints: all constraints provided from any declaration are + merged together and all are applied to the new table. 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. + + + + - - - -ERROR: ExecAppend: rejected due to CHECK constraint "constraint_name". - - - - This error occurs at runtime if one tries to insert an illegal - value into a column subject to a CHECK constraint. - - - - - - - - - - + + WITH OIDS or WITHOUT OIDS + + + This optional clause specifies whether rows of the new table + should have OIDs (object identifiers) assigned to them. The + default is to have OIDs. (If the new table inherits from any + tables that have OIDs, then WITH OIDS is forced even + if the command says WITHOUT OIDS.) + - - Description - - The CHECK constraint specifies a generic restriction on allowed values - within a column. The CHECK constraint is also allowed as a table - constraint. - - - CHECK specifies a general boolean expression involving one or more - columns of a table. A new row will be rejected if the boolean - expression evaluates to FALSE when applied to the row's values. - - - Currently, CHECK expressions cannot contain sub-selects nor refer - to variables other than fields of the current row. - - - The SQL92 standard says that CHECK column constraints may only refer - to the column they apply to; only CHECK table constraints may refer - to multiple columns. - Postgres does not enforce this restriction. - It treats column and table CHECK constraints alike. - - - - - - - PRIMARY KEY Constraint - - -[ CONSTRAINT constraint_name ] PRIMARY KEY - + + Specifying WITHOUT OIDS allows the user to suppress + generation of OIDs for rows of a table. This may be worthwhile + for large tables, since it will reduce OID consumption and + thereby postpone wraparound of the 32-bit OID counter. Once the + counter wraps around, uniqueness of OIDs can no longer be + assumed, which considerably reduces their usefulness. + + + - - Inputs - - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - - + + CONSTRAINT constraint_name + + + An optional name for a column or table constraint. If not specified, + the system generates a name. + + + - - Outputs - - - -ERROR: Cannot insert a duplicate key into a unique index. - - - - This occurs at runtime if one tries to insert a duplicate value into - a column subject to a PRIMARY KEY constraint. - - - - - + + NOT NULL + + + The column is not allowed to contain NULL values. This is + equivalent to the column constraint CHECK (column NOT NULL). + + + - - Description - - The PRIMARY KEY column constraint specifies that a column of a - table may contain only unique (non-duplicate), non-NULL values. The - definition of the specified column does not have to include an - explicit NOT NULL constraint to be included in a PRIMARY KEY - constraint. - - - Only one PRIMARY KEY can be specified for a table, whether as a - column constraint or a table constraint. - - + + NULL + + + The column is allowed to contain NULL values. This is the default. + - - - Notes - - - Postgres automatically creates - a unique index to assure - data integrity (see CREATE INDEX statement). - - - The PRIMARY KEY constraint should name a set of columns that is - different from other sets of columns named by any UNIQUE constraint - defined for the same table, since it will result in duplication - of equivalent indexes and unproductive additional runtime overhead. - However, Postgres does not specifically - disallow this. - - - - - - - 2000-02-04 - - - REFERENCES Constraint - - -[ CONSTRAINT constraint_name ] REFERENCES reftable [ ( refcolumn ) ] - [ MATCH matchtype ] - [ ON DELETE action ] - [ ON UPDATE action ] - [ [ NOT ] DEFERRABLE ] - [ INITIALLY checktime ] - - - The REFERENCES constraint specifies a rule that a column - value is checked against the values of another column. - REFERENCES can also be specified as part of - a FOREIGN KEY table constraint. - - - - Inputs - - - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - - reftable - - - The table that contains the data to check against. - - - - - - refcolumn - - - The column in reftable - to check the data against. If this is not specified, the PRIMARY KEY of the - reftable is used. - - - - - MATCH matchtype - - - There are three match types: MATCH FULL, MATCH PARTIAL, and a - default match type if none is specified. MATCH FULL will not - allow one column of a multi-column foreign key to be NULL - unless all foreign key columns are NULL. The default MATCH type - allows some foreign key columns to be NULL while other parts - of the foreign key are not NULL. MATCH PARTIAL is currently not - supported. - - - - - ON DELETE action - - - The action to do when a referenced row in the referenced table is being - deleted. There are the following actions. - - - NO ACTION - - - Produce error if foreign key violated. This is the default. - - - - - RESTRICT - - - Same as NO ACTION. - - - - - CASCADE - - - Delete any rows referencing the deleted row. - - - - - SET NULL - - - Set the referencing column values to NULL. - - - - - SET DEFAULT - - - Set the referencing column values to their default value. - - - - - - - - - ON UPDATE action - - - The action to do 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 changed, no action is done. - There are the following actions. - - - NO ACTION - - - Produce error if foreign key violated. This is the default. - - - - - RESTRICT - - - Same as NO ACTION. - - - - - CASCADE - - - Update the value of the referencing column to the new value of the - referenced column. - - - - - SET NULL - - - Set the referencing column values to NULL. - - - - - SET DEFAULT - - - Set the referencing column values to their default value. - - - - - - - - - - [ NOT ] DEFERRABLE - - - This controls whether the constraint can be deferred to the end - of the transaction. If DEFERRABLE, SET CONSTRAINTS ALL DEFERRED - will cause the foreign key to be checked only at the end of the - transaction. NOT DEFERRABLE is the default. - - - - - - INITIALLY checktime - - - checktime has two possible values - which specify the default time to check the constraint. - - - DEFERRED - - - Check constraint only at the end of the transaction. - - - - - IMMEDIATE - - - Check constraint after each statement. This is the default. - - - - - - - - - - + + This clause is only available for compatibility with + non-standard SQL databases. Its use is discouraged in new + applications. + + + + + UNIQUE (column constraint) + UNIQUE ( column_name [, ... ] ) (table constraint) - - - 2000-02-04 - - - Outputs - - - - - status - - - - - -ERROR: name referential integrity violation - key referenced from -table not found in reftable - - - - This error occurs at runtime if one tries to insert a value - into a column which does not have a matching column in the - referenced table. - - - - - - - - - - + + + The UNIQUE constraint specifies a rule that a + group of one or more distinct columns of a table may contain + only unique values. The behavior of the unique table constraint + is the same as that for column constraints, with the additional + capability to span multiple columns. + - - Description - - The REFERENCES column constraint specifies that a - column of a table must only contain values which match against - values in a referenced column of a referenced table. - - - A value added to this column is matched against the values of the - referenced table and referenced column using the given match type. - In addition, when the referenced column data is changed, actions - are run upon this column's matching data. - - + + For the purpose of a unique constraint, NULL values are not + considered equal. + - - - 1998-09-11 - - - Notes - - - Currently Postgres only supports MATCH - FULL and a default match type. In addition, the referenced - columns are supposed to be the columns of a UNIQUE constraint in - the referenced table, however Postgres - does not enforce this. - - - - - - - - Table Constraints - - - -[ CONSTRAINT name ] { PRIMARY KEY | UNIQUE } ( column [, ... ] ) -[ CONSTRAINT name ] CHECK ( constraint ) -[ CONSTRAINT name ] FOREIGN KEY ( column [, ... ] ) - REFERENCES reftable [ ( refcolumn [, ... ] ) ] - [ MATCH matchtype ] - [ ON DELETE action ] - [ ON UPDATE action ] - [ [ NOT ] DEFERRABLE ] - [ INITIALLY checktime ] - - - - - Inputs - + + Each unique table constraint must 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 it + would just be the same constraint listed twice.) + + + - + + PRIMARY KEY (column constraint) + PRIMARY KEY ( column_name [, ... ] ) (table constraint) + + + The primary key constraint specifies that a column or columns of a table + may contain only unique (non-duplicate), non-NULL values. + Technically, PRIMARY KEY is merely a + combination of UNIQUE and NOT NULL, but + identifying a set of columns as primary key also provides + meta-data about the design of the schema, as a primary key + implies that other tables + may rely on this set of columns as a unique identifier for rows. + - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - column [, ... ] - - - The column name(s) for which to define a unique index - and, for PRIMARY KEY, a NOT NULL constraint. - - - - - CHECK ( constraint ) - - - A boolean expression to be evaluated as the constraint. - - - - - - - - - - Outputs - - - - The possible outputs for the table constraint clause are the same - as for the corresponding portions of the column constraint clause. - - - - - - Description - - - - A table constraint is an integrity constraint defined on one or - more columns of a table. The four variations of Table - Constraint are: - - UNIQUE - CHECK - PRIMARY KEY - FOREIGN KEY - - - - - - - UNIQUE Constraint - - - -[ CONSTRAINT constraint_name ] UNIQUE ( column [, ... ] ) - - - - Inputs - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - column - - - A name of a column in a table. - - - - - + + Only one primary key can be specified for a table, whether as a + column constraint or a table constraint. + - - Outputs - - - - status - - - - - ERROR: Cannot insert a duplicate key into a unique index - - - This error occurs at runtime if one tries to insert a - duplicate value into a column. - - - - - - - - - - - - - - Description - - - - The UNIQUE constraint specifies a rule that a group of one or more - distinct columns of a table may contain only unique values. The - behavior of the UNIQUE table constraint is the same as that for - column constraints, with the additional capability to span multiple - columns. - - - See the section on the UNIQUE column constraint for more details. - - + + The primary key constraint should name a set of columns that is + different from other sets of columns named by any unique + constraint defined for the same table. + + + - - - Usage - - - - Prevent duplicate rows in the table distributors: - -CREATE TABLE distributors ( - did DECIMAL(3), - name VARCHAR(40), - UNIQUE(did,name) -); - - - - + + CHECK (expression) + + + CHECK clauses specify integrity constraints or tests + which new or updated rows must satisfy for an insert or update + operation to succeed. Each constraint must be an expression + producing a Boolean result. A condition appearing within a + column definition should reference that column's value only, + while a condition appearing as a table constraint may reference + multiple columns. + - - - PRIMARY KEY Constraint - - - -[ CONSTRAINT constraint_name ] PRIMARY KEY ( column [, ... ] ) - - - - Inputs - + + Currently, CHECK expressions cannot contain + subselects nor refer to variables other than columns of the + current row. + - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - column [, ... ] - - - The names of one or more columns in the table. - - - - - - - - - Outputs - - - status - - - - - ERROR: Cannot insert a duplicate key into a unique index. - - - This occurs at run-time if one tries to insert a duplicate - value into a column subject to a PRIMARY KEY constraint. - - - - - - - - - - - - Description - - The PRIMARY KEY constraint specifies a rule that a group of one - or more distinct columns of a table may contain only unique - (nonduplicate), non-null values. The column definitions of - the specified columns do not have to include a NOT NULL - constraint to be included in a PRIMARY KEY constraint. - + + - - The PRIMARY KEY table constraint is similar to that for column constraints, - with the additional capability of encompassing multiple columns. - - - Refer to the section on the PRIMARY KEY column constraint for more - information. - - - - - - 2000-02-04 - - - REFERENCES Constraint - - -[ CONSTRAINT constraint_name ] FOREIGN KEY ( column [, ... ] ) + + REFERENCES reftable [ ( refcolumn ) ] [ MATCH matchtype ] [ ON DELETE action ] [ ON UPDATE action ] (column constraint) + + FOREIGN KEY ( column [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ] [ MATCH matchtype ] [ ON DELETE action ] - [ ON UPDATE action ] - [ [ NOT ] DEFERRABLE ] - [ INITIALLY checktime ] - - - The REFERENCES constraint specifies a rule that a column value or set - of column values is - checked against the values in another table. - + [ ON UPDATE action ] + (table constraint) - - Inputs - - - - constraint_name - - - An arbitrary name given to a constraint clause. - - - - - column [, ... ] - - - The names of one or more columns in the table. - - - - - reftable - - - The table that contains the data to check against. - - - - - referenced column [, ... ] - - - One or more columns in the reftable - to check the data against. If this is not specified, the PRIMARY KEY of the - reftable is used. - - - - - MATCH matchtype - - - There are three match types: MATCH FULL, MATCH PARTIAL, and a - default match type if none is specified. MATCH FULL will not - allow one column of a multi-column foreign key to be NULL - unless all foreign key columns are NULL. The default MATCH type - allows some foreign key columns to be NULL while other parts - of the foreign key are not NULL. MATCH PARTIAL is currently not - supported. - - - - - ON DELETE action - - - The action to do when a referenced row in the referenced table is being - deleted. There are the following actions. - - - NO ACTION - - - Produce error if foreign key violated. This is the default. - - - - - RESTRICT - - - Same as NO ACTION. - - - - - CASCADE - - - Delete any rows referencing the deleted row. - - - - - SET NULL - - - Set the referencing column values to NULL. - - - - - SET DEFAULT - - - Set the referencing column values to their default value. - - - - - - - - - ON UPDATE action - - - The action to do 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 changed, no action is done. - There are the following actions. - - - NO ACTION - - - Produce error if foreign key violated. This is the default. - - - - - RESTRICT - - - Disallow update of row being referenced. - - - - - CASCADE - - - Update the value of the referencing column to the new value - of the referenced column. - - - - - SET NULL - - - Set the referencing column values to NULL. - - - - - SET DEFAULT - - - Set the referencing column values to their default value. - - - - - - - - - [ NOT ] DEFERRABLE - - - This controls whether the constraint can be deferred to the end - of the transaction. If DEFERRABLE, SET CONSTRAINTS ALL DEFERRED - will cause the foreign key to be checked only at the end of the - transaction. NOT DEFERRABLE is the default. - - - - - INITIALLY checktime - - - checktime has two - possible values which specify the default time to check the - constraint. - - - IMMEDIATE - - - Check constraint after each statement. This is the default. - - - - - DEFERRED - - - Check constraint only at the end of the transaction. - - - - - - - - - - - - - 2000-02-04 - - - Outputs - - - - - status - - - - - -ERROR: name referential integrity violation - key referenced from -table not found in reftable - - - - This error occurs at runtime if one tries to insert a value - into a column which does not have a matching column in the - referenced table. - - - - - - - - - - - - Description - - The FOREIGN KEY constraint specifies a rule that a group of one - or more distinct columns of a table is related to a group - of distinct columns in the referenced table. - + + + The REFERENCES column constraint specifies + that a group of one or more columns of the new table must only + contain values which match against values in the referenced + column(s) refcolumn + of the referenced table reftable. If refcolumn is omitted, the + primary key of the reftable is used. The + referenced columns must be the columns of a unique or primary + key constraint in the referenced table. + - - The FOREIGN KEY table constraint is similar to that for column - constraints, with the additional capability of encompassing - multiple columns. - - - Refer to the section on the FOREIGN KEY column constraint for more - information. - - + + A value added to these columns 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 a default match type if + none is specified. MATCH FULL will not allow one + column of a multi-column foreign key to be NULL unless all + foreign key columns are NULL. The default match type allows some + foreign key columns to be NULL while other parts of the foreign + key are not NULL. MATCH PARTIAL is not yet + implemented. + + + + 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 do 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. 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. This is + the default action. + + + + + + RESTRICT + + + Same as NO ACTION. + + + + + + CASCADE + + + Delete any rows referencing the deleted row, or update the + value of the referencing column to the new value of the + referenced column, respectively. + + + + + + SET NULL + + + Set the referencing column values to NULL. + + + + + + SET DEFAULT + + + Set the referencing column values to their default value. + + + + + + + + - + + DEFERRABLE or 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 may be postponed until the end of the transaction + (using the command). + NOT DEFERRABLE is the default. Only foreign + key constraints currently accept this clause. All other + constraint types are not deferrable. + + + + + INITIALLY IMMEDIATE or 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 command. + + + + + + + + + Diagnostics + + + + + + + CREATE + + + + + + + Message returned if table is successfully created. + + + + + + + + + + ERROR + + + + + + + Message returned if table creation failed. This is usually + accompanied by some descriptive text, such as: + ERROR: Relation 'table' already + exists, which occurs at runtime if the table + specified already exists in the database. + + + + - - - - Usage - + + + + Notes + + + + + Whenever an application makes use of OIDs to identify specific + rows of a table, it is recommended to create a unique constraint + on the oid column of that table, to ensure that + OIDs in the table will indeed uniquely identify rows even after + counter wraparound. Avoid assuming that OIDs are unique across + tables; if you need a database-wide unique identifier, use the + combination of tableoid and row OID for the + purpose. (It is likely that future PostgreSQL + releases will use a separate OID counter for each table, so that + it will be necessary, not optional, to include + tableoid to have a unique identifier + database-wide.) + + + + + The use of WITHOUT OIDS is not recommended + for tables with no primary key, since without either an OID or a + unique data key, it is difficult to identify specific rows. + + + + + + + PostgreSQL automatically creates an + index for each unique constraint and primary key constraint to + enforce the uniqueness. Thus, it is not necessary to create an + explicit index for primary key columns. (See for more information.) + + + + + + The SQL92 standard says that CHECK column constraints + may only refer to the column they apply to; only + CHECK table constraints may refer to multiple + columns. PostgreSQL does not enforce + this restriction; it treats column and table check constraints + alike. + + + + + + Unique constraints and primary keys are not inherited in the + current implementation. This makes the combination of + inheritance and unique constraints rather disfunctional. + + + + + + + + Examples + - Create table films and table distributors: + Create table films and table + distributors: - + CREATE TABLE films ( - code CHARACTER(5) CONSTRAINT firstkey PRIMARY KEY, - title CHARACTER VARYING(40) NOT NULL, - did DECIMAL(3) NOT NULL, - date_prod DATE, - kind CHAR(10), - len INTERVAL HOUR TO MINUTE + code CHARACTER(5) CONSTRAINT firstkey PRIMARY KEY, + title CHARACTER VARYING(40) NOT NULL, + did DECIMAL(3) NOT NULL, + date_prod DATE, + kind CHAR(10), + len INTERVAL HOUR TO MINUTE ); - + - + CREATE TABLE distributors ( - did DECIMAL(3) PRIMARY KEY DEFAULT NEXTVAL('serial'), - name VARCHAR(40) NOT NULL CHECK (name <> '') + did DECIMAL(3) PRIMARY KEY DEFAULT NEXTVAL('serial'), + name VARCHAR(40) NOT NULL CHECK (name <> '') ); - + Create a table with a 2-dimensional array: - - CREATE TABLE array ( - vector INT[][] - ); - + +CREATE TABLE array ( + 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: + 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 DECIMAL(3), - date_prod DATE, - kind CHAR(10), - len INTERVAL HOUR TO MINUTE, + code CHAR(5), + title VARCHAR(40), + did DECIMAL(3), + date_prod DATE, + kind VARCHAR(10), + len INTERVAL HOUR TO MINUTE, CONSTRAINT production UNIQUE(date_prod) ); - + - Define a CHECK column constraint: + Define a check column constraint: - + CREATE TABLE distributors ( - did DECIMAL(3) CHECK (did > 100), - name VARCHAR(40) + did DECIMAL(3) CHECK (did > 100), + name VARCHAR(40) ); - + - Define a CHECK table constraint: + Define a check table constraint: - + CREATE TABLE distributors ( - did DECIMAL(3), - name VARCHAR(40) - CONSTRAINT con1 CHECK (did > 100 AND name > '') + did DECIMAL(3), + name VARCHAR(40) + CONSTRAINT con1 CHECK (did > 100 AND name <> '') ); - + - Define a PRIMARY KEY table constraint for the table films. - PRIMARY KEY table constraints can be defined on one or more - columns of the table: + Define a primary key table constraint for the table + films. Primary key table constraints can be defined + on one or more columns of the table. - + CREATE TABLE films ( - code CHAR(5), - title VARCHAR(40), - did DECIMAL(3), - date_prod DATE, - kind CHAR(10), - len INTERVAL HOUR TO MINUTE, + code CHAR(5), + title VARCHAR(40), + did DECIMAL(3), + date_prod DATE, + kind VARCHAR(10), + len INTERVAL HOUR TO MINUTE, CONSTRAINT code_title PRIMARY KEY(code,title) ); - + - Defines a PRIMARY KEY column constraint for table distributors. - PRIMARY KEY column constraints can only be defined on one column - of the table (the following two examples are equivalent): + 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 notation. - + CREATE TABLE distributors ( - did DECIMAL(3), - name CHAR VARYING(40), + did DECIMAL(3), + name CHAR VARYING(40), PRIMARY KEY(did) ); - + - + CREATE TABLE distributors ( - did DECIMAL(3) PRIMARY KEY, - name VARCHAR(40) + did DECIMAL(3) PRIMARY KEY, + name VARCHAR(40) ); - + - + + + This assigns a literal constant default value for the column + name, and arranges for the default value of + column did to be generated by selecting the next + value of a sequence object. The default value of + modtime will 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 DECIMAL(3) CONSTRAINT no_null NOT NULL, + name VARCHAR(40) NOT NULL +); + + + + + Define a unique constraint for the name column: + + +CREATE TABLE distributors ( + did DECIMAL(3), + name VARCHAR(40) UNIQUE +); + + + The above is equivalent to the following specified as a table constraint: + + +CREATE TABLE distributors ( + did DECIMAL(3), + name VARCHAR(40), + UNIQUE(name) +); + + + - - - Compatibility - + + Compatibility + + + The CREATE TABLE conforms to SQL92 Intermediate + and to a subset of SQL99, with exceptions listed below and in the + descriptions above. + + + + Temporary Tables - - - SQL92 - - In addition to the locally visible temporary table, SQL92 also defines a - CREATE GLOBAL TEMPORARY TABLE statement, and optionally an - ON COMMIT clause: - -CREATE GLOBAL TEMPORARY TABLE table ( column type [ - DEFAULT value ] [ CONSTRAINT column_constraint ] [, ... ] ) - [ CONSTRAINT table_constraint ] [ ON COMMIT { DELETE | PRESERVE } ROWS ] - + In addition to the local temporary table, SQL92 also defines a + CREATE GLOBAL TEMPORARY TABLE statement. + Global temporary tables are also visible to other sessions. - For temporary tables, the CREATE GLOBAL TEMPORARY TABLE statement - names a new table visible to other clients and defines the table's columns - and constraints. + For temporary tables, there is an optional ON COMMIT clause: + +CREATE { GLOBAL | LOCAL } TEMPORARY TABLE table ( ... ) [ ON COMMIT { DELETE | PRESERVE } ROWS ] + + + The ON COMMIT clause specifies whether or not + the temporary table should be emptied of rows whenever + COMMIT is executed. If the ON + COMMIT clause is omitted, SQL92 specifies that the default is + ON COMMIT DELETE ROWS. However, the behavior of + PostgreSQL is always like ON + COMMIT PRESERVE ROWS. + + + + <literal>NULL</literal> <quote>Constraint</quote> + - The optional ON COMMIT clause of CREATE TEMPORARY TABLE specifies - whether or not the temporary table should be emptied of rows - whenever COMMIT is executed. If the ON COMMIT clause is omitted, SQL92 - specifies that the default is ON COMMIT DELETE ROWS. However, - Postgres' behavior is always like - ON COMMIT PRESERVE ROWS. + The NULL constraint (actually a + non-constraint) is a PostgreSQL + extension to SQL92 that is included for compatibility with some + other RDBMSes (and for symmetry with the NOT + NULL constraint). Since it is the default for any + column, its presence is simply noise. - - - - UNIQUE clause - - - SQL92 specifies some additional capabilities for UNIQUE: - - - Table Constraint definition: - - -[ CONSTRAINT constraint_name ] UNIQUE ( column [, ... ] ) - [ { INITIALLY DEFERRED | INITIALLY IMMEDIATE } ] - [ [ NOT ] DEFERRABLE ] - - - - - Column Constraint definition: - - -[ CONSTRAINT constraint_name ] UNIQUE - [ {INITIALLY DEFERRED | INITIALLY IMMEDIATE} ] - [ [ NOT ] DEFERRABLE ] - - - + - - - NULL clause - - - The NULL constraint (actually a non-constraint) is a - Postgres extension to SQL92 that is - included for symmetry with the NOT NULL clause (and for compatibility - with some other RDBMSes). Since it is the - default for any column, its presence is simply noise. - -[ CONSTRAINT constraint_name ] NULL - - - - - - - NOT NULL clause - - - - SQL92 specifies some additional capabilities for NOT NULL: - -[ CONSTRAINT constraint_name ] NOT NULL - [ {INITIALLY DEFERRED | INITIALLY IMMEDIATE} ] - [ [ NOT ] DEFERRABLE ] - - - - - + + An assertion is a special type of integrity constraint and shares + the same namespace as other constraints. However, an assertion is + not necessarily dependent on one particular table as constraints + are, so SQL92 provides the CREATE ASSERTION + statement as an alternate method for defining a constraint: - - - CONSTRAINT clause - - - SQL92 specifies some additional capabilities for constraints, - and also defines assertions and domain constraints. - - - Postgres does not yet support - either domains or assertions. - - - - - An assertion is a special type of integrity constraint and shares - the same namespace as other constraints. However, an assertion is - not necessarily dependent on one particular table as - constraints are, so SQL-92 provides the CREATE ASSERTION statement - as an alternate method for defining a constraint: - - + CREATE ASSERTION name CHECK ( condition ) - - + + + + + PostgreSQL does not implement assertions at present. + + + + - - table constraint definition: - -[ CONSTRAINT constraint_name ] - CHECK ( VALUE condition ) - [ {INITIALLY DEFERRED | INITIALLY IMMEDIATE} ] - [ [ NOT ] DEFERRABLE ] - - + + + Inheritance - - column constraint definition: - -[ CONSTRAINT constraint_name ] - CHECK ( VALUE condition ) - [ {INITIALLY DEFERRED | INITIALLY IMMEDIATE} ] - [ [ NOT ] DEFERRABLE ] - - - - - - - - PRIMARY KEY clause - - - SQL92 specifies some additional capabilities for PRIMARY KEY: - - - Table Constraint definition: - -[ CONSTRAINT constraint_name ] PRIMARY KEY ( column [, ... ] ) - [ {INITIALLY DEFERRED | INITIALLY IMMEDIATE} ] - [ [ NOT ] DEFERRABLE ] - - - - Column Constraint definition: - -[ CONSTRAINT constraint_name ] PRIMARY KEY - [ {INITIALLY DEFERRED | INITIALLY IMMEDIATE} ] - [ [ NOT ] DEFERRABLE ] - - - - - - - Inheritance - - - Multiple inheritance via the INHERITS clause is a - Postgres language extension. - SQL99 (but not SQL92) defines single inheritance using a different - syntax and different semantics. SQL99-style inheritance is not yet - supported by Postgres. - - - - - - Object IDs - - - The Postgres concept of OIDs is not - standard. SQL99 (but not SQL92) has a notion of object ID, but - the syntax and semantics are different --- SQL99 associates OIDs - with individual values, not with rows. - - + Multiple inheritance via the INHERITS clause is + a PostgreSQL language extension. SQL99 + (but not SQL92) defines single inheritance using a different + syntax and different semantics. SQL99-style inheritance is not + yet supported by PostgreSQL. + + + + Object IDs + + + The PostgreSQL concept of OIDs is not + standard. + + + + + + + See Also + + + + + diff --git a/doc/src/sgml/ref/create_table_as.sgml b/doc/src/sgml/ref/create_table_as.sgml index a0144ab658..8ebc19c2a7 100644 --- a/doc/src/sgml/ref/create_table_as.sgml +++ b/doc/src/sgml/ref/create_table_as.sgml @@ -1,112 +1,26 @@ - - CREATE TABLE AS - + CREATE TABLE AS SQL - Language Statements + - - CREATE TABLE AS - - - create a new table from the results of a query - + CREATE TABLE AS + create a new table from the results of a query + - - 2001-03-03 - - -CREATE [ TEMPORARY | TEMP ] TABLE table [ (column [, ...] ) ] - AS select_clause + +CREATE [ [ LOCAL ] { TEMPORARY | TEMP } ] TABLE table_name [ (column_name [, ...] ) ] + AS query - - - - 1998-09-22 - - - Inputs - - - - - - TEMPORARY or TEMP - - - If specified, the table is created only within this session, and is - automatically dropped on session exit. - Existing permanent tables with the same name are not visible - (in this session) while the temporary table exists. - Any indexes created on a temporary table are automatically - temporary as well. - - - - - - table - - - The name of the new table to be created. - This table must not already exist. However, a temporary table - can be created that has the same name as an existing permanent - table. - - - - - - column - - - The name of a column. Multiple column names can be specified using - a comma-delimited list of column names. If column names are not - provided, they are taken from the output column names of the - SELECT query. - - - - - - select_clause - - - A valid query statement. Refer to - - for a description of the allowed syntax. - - - - - - - - - - 1998-09-22 - - - Outputs - - - - Refer to - - and - - for a summary of possible output messages. - - - + 2001-03-20 @@ -117,28 +31,135 @@ CREATE [ TEMPORARY | TEMP ] TABLE table [ ( CREATE TABLE AS creates a table and fills it with data computed by a SELECT command. The - table columns have the names and datatypes associated with the + table columns have the names and data types associated with the output columns of the SELECT (except that you - can override the SELECT column names by giving - an explicit list of column names). + can override the column names by giving an explicit list of new + column names). - CREATE TABLE AS bears some resemblance to creating - a view, but it is really quite different: it creates a new table and - evaluates the SELECT just once to fill the new table - initially. The new table will not track subsequent changes to - the source tables of the SELECT. In contrast, - a view re-evaluates the given SELECT whenever queried. - - - - This command is functionally equivalent to - , - but it is preferred since it is less likely to be confused with - other uses of the SELECT ... INTO syntax. + CREATE TABLE AS bears some resemblance to + creating a view, but it is really quite different: it creates a new + table and evaluates the query just once to fill the new table + initially. The new table will not track subsequent changes to the + source tables of the query. In contrast, a view re-evaluates the + underlying SELECT statements whenever it is + queried. + + + Parameters + + + + [LOCAL] TEMPORARY or [LOCAL] TEMP + + + If specified, the table is created as a temporary table. + Temporary tables are automatically dropped at the end of a + session. Existing persistent tables with the same name are not + visible to the current session while the temporary table exists. + Any indexes created on a temporary table are automatically + temporary as well. + + + + The LOCAL word is optional. + + + + + + table_name + + + The name of the new table to be created. This table must not + already exist. However, a temporary table can be created that + has the same name as an existing permanent table. + + + + + + column_name + + + The name of a column in the new table. Multiple column names can + be specified using a comma-delimited list of column names. If + column names are not provided, they are taken from the output + column names of the query. + + + + + + query + + + A query statement (that is, a SELECT + command). Refer to + + for a description of the allowed syntax. + + + + + + + + Diagnostics + + + Refer to and + + for a summary of possible output messages. + + + + + Notes + + + This command is functionally equivalent to , but it is preferred since it is less + likely to be confused with other uses of the SELECT + ... INTO syntax. + + + + + Compatibility + + + This command is modeled after an Oracle + feature. There is no command with equivalent functionality in + SQL92 or SQL99. However, a combination of CREATE + TABLE and INSERT ... SELECT can + accomplish the same thing with little more effort. + + + + + History + + + The CREATE TABLE AS command has been available + since PostgreSQL 6.3. + + + + + See Also + + + + + + + + + @@ -89,7 +89,7 @@ where from_item can be: All other inputs are described in detail for - . + . @@ -103,9 +103,9 @@ where from_item can be: Refer to - + and - + for a summary of possible output messages. @@ -128,7 +128,7 @@ where from_item can be: - + is functionally equivalent to SELECT INTO. CREATE TABLE AS is the recommended syntax, since SELECT INTO is not standard. In fact, this form of diff --git a/doc/src/sgml/stylesheet.dsl b/doc/src/sgml/stylesheet.dsl index 1b2d55ce86..80d9462d23 100644 --- a/doc/src/sgml/stylesheet.dsl +++ b/doc/src/sgml/stylesheet.dsl @@ -1,4 +1,4 @@ - + @@ -123,6 +123,16 @@ ;;; XXX The above is very ugly. It might be better to run 'tidy' on ;;; the resulting *.html files. + +;; Format multiple terms in varlistentry vertically, instead +;; of comma-separated. +(element (varlistentry term) + (make sequence + (process-children-trim) + (if (not (last-sibling?)) + (make empty-element gi: "BR") + (empty-sosofo)))) + ]]>