DELETE

DELETE ... commands

Purpose

Mark records in the active table for deletion

Syntax

DELETE [<scope>]

[FOR <condition>]

[WHILE <condition>]

See Also

ERASE, LOCATE, PACK, RECALL, SCOPE, SEEK, SET DELETED, SET FILTER, SQL DELETE, TRUNCATE TABLE, USE, ZAP

Description

The DELETE command marks records in the active table for deletion. Any records which have been marked for deletion with the DELETE command can be reinstated using the RECALL command.

Records that are marked for deletion are only physically removed from the table after the PACK command has been issued. If the table is indexed, then Lianja will process the records in the table in the order of the master index file. If the active table is shareable, then Lianja will automatically lock each record in turn, mark it for deletion if required, then unlock the record.

<scope>

The default SCOPE is the current record unless a FOR or WHILE condition is specified.

FOR <condition>

If the FOR clause is specified, then only those records which satisfy the <condition> are deleted. The default SCOPE is ALL.

WHILE <condition>

The WHILE clause can be used to restrict the number of records checked against a particular FOR <condition>, therefore optimizing the deletion process. The default SCOPE is REST.

Example

use patrons index names, events
delete all for event = "HAMLET"
 
use patrons index events, names
seek "OPERA"
delete rest;
  for date < date();
  while event = "OPERA"