9. LOCK-LATCH (8 bytes)

While a password can be used to provide security to a table in a library, the LOCK-LATCH provides control for updating a table that is open for write in a multi-user environment (CICS, IMS, multitasking batch, and VTS).

To control the users or transactions that are authorized to perform updates in a multi-user environment after a table is open for write, place a password in the LOCK-LATCH field when Opening for Write using either an OW, DT or CN command. Only the update commands that have the same password in the LOCK-LATCH field are authorized to perform the update command.

This field is not edited and may contain any value. Leaving this field blank indicates a null LOCK-LATCH. So, although LOW-VALUES are considered a valid LOCK-LATCH, this is not recommended. If the table is opened for write with a null LOCK-LATCH any update command can modify the table regardless of the value in the LOCK-LATCH field.

A table that is opened for write with either a null LOCK-LATCH or a password initialized LOCK-LATCH cannot have the LOCK-LATCH modified in any way until the table is closed (CL) or released (RL).

If the LOCK-LATCH is forgotten or lost, the master password must be used to access the table. For more information, please contact your tableBASE administrator.

If the Data Table is closed or open for read, an Alternate Index that is opened for write with a LOCK-LATCH password will force the Data Table to adopt this LOCK-LATCH password and be opened for write. Once this Alternate Index is closed, and there are no other Alternate Indexes open, the Data Table’s status is set to open for read and the LOCK-LATCH is released.