The COMPRESSION clause sets the compression method for the column. If not specified, the column data type's default collation is used. The COLLATE clause assigns a collation to the column (which must be of a collatable data type). For more information on the data types supported by PostgreSQL, refer to Chapter 8. The name of a column to be created in the new table. But the CREATE TABLE command can add defaults and constraints to the table and can specify storage parameters. 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. A typed table is tied to its type for example the table will be dropped if the type is dropped (with DROP TYPE. OF type_nameĬreates a typed table, which takes its structure from the specified composite type (name optionally schema-qualified). The name (optionally schema-qualified) of the table to be created.
Note that there is no guarantee that the existing relation is anything like the one that would have been created.
IF NOT EXISTSĭo not throw an error if a relation with the same name already exists.
PGCLI CREATE TABLE EXAMPLE SERIAL
If this is specified, any sequences created together with the unlogged table (for identity or serial columns) are also created as unlogged. Any indexes created on an unlogged table are automatically unlogged as well. The contents of an unlogged table are also not replicated to standby servers. However, they are not crash-safe: an unlogged table is automatically truncated after a crash or unclean shutdown. Data written to unlogged tables is not written to the write-ahead log (see Chapter 30), which makes them considerably faster than ordinary tables. If specified, the table is created as an unlogged table. This presently makes no difference in PostgreSQL and is deprecated see Compatibility below. Optionally, GLOBAL or LOCAL can be written before TEMPORARY or TEMP. 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. For this reason, appropriate vacuum and analyze operations should be performed via session SQL commands. The autovacuum daemon cannot access and therefore cannot vacuum or analyze temporary tables. Any indexes created on a temporary table are automatically temporary as well. The default search_path includes the temporary schema first and so identically named existing permanent tables are not chosen for new plans while the temporary table exists, unless they are referenced with schema-qualified names. Temporary tables are automatically dropped at the end of a session, or optionally at the end of the current transaction (see ON COMMIT below). If specified, the table is created as a temporary table. To be able to create a table, you must have USAGE privilege on all column types or the type in the OF clause, respectively. 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. A table constraint definition is not tied to a particular column, and it can encompass more than one column. A column constraint is defined as part of a column definition. There are two ways to define constraints: table constraints and column constraints.
A constraint is an SQL object that helps define the set of valid values in the table in various ways.
PGCLI CREATE TABLE EXAMPLE UPDATE
The optional constraint clauses specify constraints (tests) that new or updated rows must satisfy for an insert or update operation to succeed. Therefore, tables cannot have the same name as any existing data type in the same schema. 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.ĬREATE TABLE also automatically creates a data type that represents the composite type corresponding to one row of the table. Temporary tables exist in a special schema, so a schema name cannot be given when creating a temporary table. Otherwise it is created in the current schema. ) then the table is created in the specified schema. If a schema name is given (for example, CREATE TABLE myschema.mytable. The table will be owned by the user issuing the command. CREATE ĬREATE TABLE will create a new, initially empty table in the current database.
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