Difference between revisions of "DELETE"
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==Purpose== | ==Purpose== | ||
Mark records in the active table for deletion | Mark records in the active table for deletion | ||
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==See Also== | ==See Also== | ||
| − | [[ERASE]], [[LOCATE]], [[PACK]], [[RECALL]], [[SEEK]], [[SET COMPATIBLE]], [[SET DELETED]], [[SET FILTER]], [[ZAP]] | + | [[ERASE]], [[LOCATE]], [[PACK]], [[RECALL]], [[SCOPE]], [[SEEK]], [[SET COMPATIBLE]], [[SET DELETED]], [[SET FILTER]], [[USE]], [[ZAP]] |
==Description== | ==Description== | ||
| − | The DELETE command marks records in the active table for deletion. | + | 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. |
| − | If | + | 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 Recital will process the records in the table in the order of the master index file. If the active table is shareable, then Recital 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>==== | ====FOR <condition>==== | ||
| − | If the FOR clause is specified, then only those records which satisfy the <condition> are deleted. | + | If the FOR clause is specified, then only those records which satisfy the <condition> are deleted. The default [[SCOPE]] is ALL. |
====WHILE <condition>==== | ====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 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. |
| + | At the end of a DELETE operation with a FOR or WHILE condition, the record pointer is positioned to EOF() if SET COMPATIBLE TO <XBASE> is in effect. | ||
==Example== | ==Example== | ||
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seek "OPERA" | seek "OPERA" | ||
delete rest; | delete rest; | ||
| − | for date<date(); | + | for date < date(); |
while event = "OPERA" | while event = "OPERA" | ||
</code> | </code> | ||
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==Products== | ==Products== | ||
| − | Recital | + | Recital Server, Recital |
[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:Commands]] | [[Category:Commands]] | ||
| + | [[Category:Table Basics]] | ||
| + | [[Category:Table Basics Commands]] | ||
| + | [[Category:Data Commands]] | ||
Latest revision as of 16:20, 3 September 2010
Contents
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 COMPATIBLE, SET DELETED, SET FILTER, 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 Recital will process the records in the table in the order of the master index file. If the active table is shareable, then Recital 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.
At the end of a DELETE operation with a FOR or WHILE condition, the record pointer is positioned to EOF() if SET COMPATIBLE TO <XBASE> is in effect.
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"
Products
Recital Server, Recital
