8/18/2023 0 Comments Postgresql rename tableIn fact all the options that can be applied to a column description in CREATE TABLE can be used here. You can also define constraints on the column at the same time, using the usual syntax:ĪLTER TABLE products ADD COLUMN description text CHECK (description '') To avoid a potentially lengthy update operation, particularly if you intend to fill the column with mostly nondefault values anyway, it may be preferable to add the column with no default, insert the correct values using UPDATE, and then add any desired default as described below. However, if the default value is volatile (e.g., clock_timestamp()) each row will need to be updated with the value calculated at the time ALTER TABLE is executed. Instead, the default value will be returned the next time the row is accessed, and applied when the table is rewritten, making the ALTER TABLE very fast even on large tables. For more information on the use of statistics by the PostgreSQL query planner, refer to Section 14.2.From PostgreSQL 11, adding a column with a constant default value no longer means that each row of the table needs to be updated when the ALTER TABLE statement is executed. The target can be set in the range 0 to 10000 alternatively, set it to -1 to revert to using the system default statistics target ( default_statistics_target). Since expressions lack a unique name, we refer to them using the ordinal number of the index column. This form sets the per-column statistics-gathering target for subsequent ANALYZE operations, though can be used only on index columns that are defined as an expression. ALTER column_number SET STATISTICS integer As with SET, a REINDEX might be needed to update the index entirely. This form resets one or more index-method-specific storage parameters to their defaults. Note that the index contents will not be modified immediately by this command depending on the parameter you might need to rebuild the index with REINDEX to get the desired effects. See CREATE INDEX for details on the available parameters. This form changes one or more index-method-specific storage parameters for the index. An index that's marked as dependent on an extension is automatically dropped when the extension is dropped. This form marks the index as dependent on the extension, or no longer dependent on that extension if NO is specified. An attached index cannot be dropped by itself, and will automatically be dropped if its parent index is dropped. The named index must be on a partition of the table containing the index being altered, and have an equivalent definition. ATTACH PARTITIONĬauses the named index to become attached to the altered index. Note that system catalogs will not be moved by this command, use ALTER DATABASE or explicit ALTER INDEX invocations instead if desired. If the NOWAIT option is specified then the command will fail if it is unable to acquire all of the locks required immediately. This form also supports OWNED BY, which will only move indexes owned by the roles specified. All indexes in the current database in a tablespace can be moved by using the ALL IN TABLESPACE form, which will lock all indexes to be moved and then move each one. To change the tablespace of an index, you must own the index and have CREATE privilege on the new tablespace. This form changes the index's tablespace to the specified tablespace and moves the data file(s) associated with the index to the new tablespace. Renaming an index acquires a SHARE UPDATE EXCLUSIVE lock. If the index is associated with a table constraint (either UNIQUE, PRIMARY KEY, or EXCLUDE), the constraint is renamed as well. The RENAME form changes the name of the index.
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