Difference between revisions of "LOCKF"
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==Class== | ==Class== | ||
Manual Locking | Manual Locking | ||
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seek "OPERA" | seek "OPERA" | ||
if found() | if found() | ||
| − | + | lockf | |
| − | + | replace price with price * 1.2 | |
| − | + | unlock | |
endif | endif | ||
</code> | </code> | ||
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[[Category:Documentation]] | [[Category:Documentation]] | ||
[[Category:Commands]] | [[Category:Commands]] | ||
| + | [[Category:Manual Locking]] | ||
| + | [[Category:Manual Locking Commands]] | ||
Revision as of 08:42, 2 June 2009
Class
Manual Locking
Purpose
Lock a table for exclusive use
Syntax
LOCKF
See Also
CLEAR LOCKS, CLOSE DATABASES, DISPLAY STATUS, FLOCK(), LOCKR, RLOCK(), SET EXCLUSIVE, UNLOCK, USE, QUIT
Description
The LOCKF command provides the facility to lock a table for exclusive use. LOCKF works in a similar way to the FLOCK() function, except that program execution is suspended until the lock is granted. In order to prepare a table for locking, SET EXCLUSIVE OFF must be in effect when you USE the table. If you only want to lock a particular record, then you should use LOCKR rather than LOCKF.
The LOCKF command works in conjunction with the UNLOCK command. Whenever you issue CLOSE DATABASES, UNLOCK, USE, QUIT or CLEAR LOCKS, then any active locks will be removed. You can see any active locks using the DISPLAY STATUS command. This command is not normally used, as the Recital/4GL supports automatic file and record locking.
Example
set exclusive off use patrons index events, names seek "OPERA" if found() lockf replace price with price * 1.2 unlock endif
Products
Recital Database Server, Recital Mirage Server, Recital Terminal Developer
