Category: ZIM 4GL Language Reference

Make Zim Server generate implicit transactions.

Syntax

SET IMPLICITTRANS OFF | ON

Comments

This command is ignored and has no effect on Zim Server. It is only accepted for backward compatibility.

Syntax

SET TIMEOUT [num]

This command is ignored by Zim 9. Its approximate equivalent is the Zim Server configuration option Pending Timeout.

Enables or disables the checkpoint activity over changed buffers.

Syntax

SET CHECKPOINT ON|OFF

Comments

The CHECKPOINT option is set ON by default.

When CHECKPOINT is ON, all data changed in transactions successfully committed by users is sent to a checkpoint file which then is later committed to the database. In this way, the server can guarantee modifications and rollback transactions if some are aborted. It also allows the backup of databases in real time.

When CHECKPOINT is OFF, all data changed in transactions is sent immediately to the database. There is no guarantee of the data being written in case a transaction is aborted. Only one user can perform this kind of operation and the database remains in exclusive access for this user. This options simulates a single-user behaviour and is mainly designed to load big amounts of data as when a fresh database is being created or imported from another version of Zim.

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.

Controls if virtual fields can be output using a LIST command.

Syntax

SET OUTPUT VIRTUALFIELD ON|OFF

Comments

The OUTPUT VIRTUALFIELD option is set ON by default.

Normally, LIST can output virtual fields. To suppress the output of virtual fields, set OUTPUT VIRTUALFIELD to OFF.

See Also

LIST

Specifies if implicit transactions are to be retried automatically if a deadlock or a time-out occurs.

Syntax

SET AUTORETRY ON|OFF

Comments

The AUTORETRY option is set OFF by default.

When AUTORETRY is ON, implicit transactions that fail because of deadlock or time-outs will be retried until they finally succeed or an internal maximum number of retries is reached (which can be set by the database configuration option “transaction retries”).

If these implicit transactions fail, then an error message is printed.

Controls how trailing blanks in output lines are treated.

Syntax

SET OUTPUT TRIM ON|OFF

Comments

The OUTPUT TRIM option is set OFF by default.

Normally, trailing blanks are retained in the output stream. To remove trailing blanks, set OUTPUT TRIM to ON. This option works with single lines of text; to trim trailing blanks in fields, use $trim.

See Also

$trim

LIST

OUTPUT

REPORT FROM

Document containing Zim statements to be executed by the Zim Database Agent when it exits.

Syntax

SERVBYE

Comments

Refer to the description of IF.

Refer to the description of CASE.