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TRUNCATE — empties a table
TRUNCATE TABLE [
TRUNCATE operates on the table instead of individual rows. Therefore the command
TRUNCATE TABLE removes all rows from a table without logging individual row deletions It is more efficient than using DELETE without a WHERE clause.
The user must have the
DELETE privilege on the table in order to invoke
TRUNCATE on it. After execution of
TRUNCATE TABLE, disk space is not reclaimed immediately. The NuoDB Check tool (see NuoDB Check) needs to run to reclaim this new unused disk space.
Name (optionally schema-qualified) of the table to be truncated.
Note that inside an explicit transaction,
ROLLBACK has no effect when using
TRUNCATE TABLE, unlike
DELETE, which can be rolled back inside an explicit transaction.
START TRANSACTION; CREATE TABLE tab_truncate (col1 STRING); INSERT INTO tab_truncate VALUES ('row1'),('row2'),('row3'); SELECT * FROM tab_truncate; COL1 ----- row1 row2 row3 ROLLBACK; SELECT * FROM tab_truncate; /* There are no records selected */