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DELETE
Mark records for deletion
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Syntax
DELETE [<scope>] [WHILE <lCondition>]
[FOR <lCondition>]
Arguments
<scope> is the portion of the current database file to DELETE. If a
scope is not specified, DELETE acts only on the current record. If a
conditional clause is specified, the default becomes ALL records.
WHILE <lCondition> specifies the set of records meeting the
condition from the current record until the condition fails.
FOR <lCondition> specifies the conditional set of records to DELETE
within the given scope.
Description
DELETE is a database command that tags records so they can be filtered
with SET DELETED ON, queried with DELETED(), or physically removed from
the database file with PACK. In addition, display commands such as LIST
and DISPLAY identify deleted records with an asterisk (*) character.
Once records are deleted, you can reinstate them by using RECALL. If
you want to remove all records from a database file, use ZAP instead of
DELETE ALL and PACK.
Any deleted record can be recalled as long as the PACK or ZAP command
has not been issued. Once the PACK or ZAP command has been issued, the
deleted data cannot be retrieved.
In a network environment, DELETE requires the current record be locked
with RLOCK() if you are deleting a single record. If you are deleting
several records, the current database file must be locked with FLOCK()
or USEed EXCLUSIVEly. Refer to the "Network Programming" chapter in the
Programming and Utilities Guide for more information.
Notes
. DELETE with SET DELETED ON: If the current record is deleted
with SET DELETED ON, it will be visible until the record pointer is
moved.
Examples
. This example demonstrates use of the FOR clause to mark a set
of records for deletion:
USE Sales INDEX Salesman NEW
DELETE ALL FOR Inactive
Files Library is CLIPPER.LIB.
See Also:
DBEVAL()
DELETED()
FLOCK()
PACK
RECALL
RLOCK()
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