Difference between revisions of "LOCK TABLE"

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==Example==
 
==Example==
 
<code lang="recital">
 
<code lang="recital">
LOCK TABLE staff
+
LOCK TABLE staff IN SHARE MODE
IN SHARE MODE;
+
 
</code>
 
</code>
  

Latest revision as of 17:28, 22 December 2009

Purpose

Locks a table to control access by other processes


Syntax

LOCK TABLE [<database>!]<table> IN SHARE | EXCLUSIVE MODE [NOWAIT]


See Also

COPY DATABASE, CREATE DATABASE, DISPLAY SCHEMAS, INSERT, LIST SCHEMAS, OPEN DATABASE, SELECT, SET AUTOCATALOG, UPDATE, USE


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 Server, Recital