TRUNCATE TABLE

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4D v16.3

TRUNCATE TABLE


TRUNCATE TABLE {( aTable )}

Parameter	Type	Description
aTable	Table	Table where all records will be deleted or Default table if this parameter is omitted

Description

The TRUNCATE TABLE command quickly deletes all the records of aTable. After calling the command, there is no longer any current selection or current record.

The effect of this command is similar to that of an ALL RECORDS / DELETE SELECTION sequence; however, its functioning differs on the following points:

No trigger is called
The referential integrity of the data is not checked.
No transaction must be underway in the process executing TRUNCATE TABLE. If this if the case, the command does nothing and the OK system variable is set to 0
If one or more records are locked by another process, the command fails: an error is generated and the OK system variable is set to 0. The LockedSet system set is not created.
If aTable is already empty, TRUNCATE TABLE does nothing and sets the OK variable to 1.
If aTable is in read-only, TRUNCATE TABLE does nothing and sets the OK variable to 0.
The operation is recorded in the log file if there is one.

The TRUNCATE TABLE command should therefore be used with caution but is very effective in certain cases, for example, such as quickly deleting temporary data

Note: The concept and functioning of this command is similar to that of the SQL TRUNCATE (TABLE) command.

System variables and sets

If the command has been executed correctly, the OK system variable is set to 1. Otherwise, it is set to 0.