Committing changes to your database

When you are editing a database, your changes are held in IMS buffers until they are written to the database data set files, in a process called committing your data.

As you first enter the Database Positioning panel during the Edit dialog, FM/IMS issues a checkpoint, marking the current state of the segment data. Each time that you commit your data (via a SAVE or EXIT command, or when FM/IMS automatically saves the data for you), a new checkpoint is issued. At any time up until you commit the data, you can revert to the last checkpoint position by undoing or canceling your changes. If you are working in DLI mode and the Dynamic Backout option is selected, FM/IMS reverts to the last checkpoint position when an abend occurs. If you are working in BMP mode, this rollback occurs automatically.

The point at which data is committed to the database depends upon the setting of the AUTOSAVE option.

  • If AUTOSAVE is set to OFF, your changes are stored in the IMS buffers as you work, but not committed to the database until you issue a SAVE command or you exit from the Database Positioning panel. You can change more than one segment occurrence at a time and change occurrences in more than one segment type before committing the changes to the database.
  • If AUTOSAVE is set to ON, your changes are automatically committed to the database when the number of changes recorded in a counter reaches the value specified in either the Edit Checkpoint Frequency field or the Change All Checkpoint Frequency field in the DLI Mode Options panel (option 0.6.4) or the BMP Mode Options panel (option 0.7.2).
Note: If you are working in DLI mode and are using a Static PSB that does not have an I/O PCB, AUTOSAVE is not available and the SAVE, UNDO and CANCEL commands are not active. Your changes can only be committed to the database or cancelled when you leave the Database Positioning panel. Use the Exit function key (F3) from that panel to save your changes; use the Cancel function key (F12) to discard your changes.

The tasks described in this section are: