LOCK TABLE
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Revision as of 16:11, 19 March 2009 by Yvonnemilne (Talk | contribs)
Contents
LOCK TABLE
Class
SQL Applications
Purpose
Locks a table to control access by other processes
Syntax
LOCK TABLE [<database>!]<table> IN SHARE | EXCLUSIVE MODE [NOWAIT]
See Also
Description
To lock tables to control access by other processes. The LOCK TABLE statement locks an entire table to restrict access by other users or transactions. There are no prerequisites required to perform this operation.
| Keywords | Description |
|---|---|
| database | The name of the database to which the table belongs. Databases in Recital are implemented as directories containing files that correspond to the tables and associated files in the database. Operating System file protection can be applied individually to the files for added security. The directory is a sub-directory of the Recital data directory. The environment variable / symbol DB_DATADIR points to the current Recital data directory and can be queried using the GETENV() function. Files from other directories can be added to the database using the ADD TABLE command or via the database catalog and SET AUTOCATALOG functionality. The '!' character must be included between the database name and the table name. |
| table | The name of the table to set the lock mode on. |
| SHARE | Share locks allow queries on locked tables, but prevent updates. |
| EXCLUSIVE | This lock denies access by any other process to the table |
| NOWAIT | This specifies that if a lock cannot be granted immediately during an update, then an error should be returned. |
Example
LOCK TABLE staff IN SHARE MODE;
Products
Recital Database Server, Recital Mirage Server, Recital Terminal Developer
