|PostgreSQL Reference Manual - Volume 1 - SQL Language Reference|
by The PostgreSQL Global Development Group
Paperback (6"x9"), 716 pages
RRP £32.00 ($49.95)
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TRUNCATE -- empty a table or set of tables
TRUNCATE [ TABLE ] name [, ...] [ CASCADE | RESTRICT ]
TRUNCATE quickly removes all rows from a set of
tables. It has the same effect as an unqualified
DELETE on each table, but since it does not actually
scan the tables it is faster. This is most useful on large tables.
- The name (optionally schema-qualified) of a table to be truncated.
Automatically truncate all tables that have foreign-key references
to any of the named tables, or to any tables added to the group
- Refuse to truncate if any of the tables have foreign-key references from tables that are not to be truncated. This is the default.
Only the owner of a table may
TRUNCATE cannot be used on a table that has foreign-key
references from other tables, unless all such tables are also truncated
in the same command. Checking validity in such cases would require table
scans, and the whole point is not to do one. The
option can be used to automatically include all dependent tables--but be very careful when using this option, else you might lose data you
did not intend to!
TRUNCATE will not run any user-defined
DELETE triggers that might exist for the tables.
Truncate the tables
TRUNCATE TABLE bigtable, fattable;
Truncate the table
othertable, and cascade to any tables
that are referencing
othertable via foreign-key
TRUNCATE othertable CASCADE;
There is no
TRUNCATE command in the SQL standard.
|ISBN 0954612027||PostgreSQL Reference Manual - Volume 1 - SQL Language Reference||See the print edition|