SET DATABASE ACCESS

Sets an exclusive or shared access to a database.

Syntax

SET DATABASE ACCESS EXCLUSIVE|SHARED

Comments

This command enables a specific user (usually the database administrator) to grant himself/herself exclusive access to a ZIM database. Under normal conditions, database access is shared among users; however, in some situations, the administrator may want exclusive access to the database (i.e. urgent program recompilation or database maintenance).  To obtain exclusive access the database administrator can issue the command with the option EXCLUSIVE.

At this point the ZIM Server stops accepting new incoming transactions, waits for the existing transactions to end and then grants exclusive Database access to the specific user.  Any subsequent requests from other users are kept in a suspended state. As soon as all transactions stop, all files are closed. Therefore, it is possible to issue operating system commands to deal with physical database files.

When the exclusive access is no longer required, the command can be issued with the option SHARED.

From this point, Zim Server activity is resumed and all suspended state users can continue with their normal processing.

At the end of the session that set the exclusive access and if the access was not reverted to shared, then Zim Server automatically sets the shared attribute to that database.