Control Commands › General Considerations › Database Currencies

Database Currencies

Database currencies are established by the last database command in an operative dialog. Currencies are saved and made available to lower level dialogs and to the dialog that established the currencies if control returns to that dialog from a lower application level.

Considerations

The following considerations apply to currencies:

• Database currencies are cumulative.

  Currencies established by each dialog or dialog function are passed to lower level dialogs along with any currencies received from a higher level dialog. A lower level dialog can establish new currencies, which are passed to the next lower level dialog along with the currencies already established.

• All database currencies established for a dialog are released when a dialog or a dialog function becomes nonoperative.

  Unless the dialog or dialog function receiving control specifies the NOSAVE keyword on a LINK command, it establishes its own currencies. These currencies are established either by restoring the currencies saved when it originally passed control or by using currencies previously established by a higher level dialog. The following diagram shows currencies in an CA ADS application.

Currency Action

         DIALOG A
  ┌──────────────────────┐
  │     Currencies       │
  │Received   Established│        DIALOG A executes and establishes
  │           EMP      A ◄───┐    current records of two sets.
  │NONE       DEPT     X │   │
  │                      │   │
  └──────────┬───────────┘   │
             │   LINK        │
             v               │    DIALOG A links to DIALOG B and
         DIALOG B            │    establishes a current record of
  ┌──────────────────────┐   │    a third set.
  │     Currencies       │   │
  │Received   Established│   │
  │EMP    A   EMP      A │   │
  │DEPT   X   DEPT     X │   │
  │           OFFICE   M │   │
  └──────────┬───────────┘   │
             │   INVOKE      │
             v               │    DIALOG B invokes DIALOG C.
         DIALOG C            │
  ┌──────────────────────┐   │
  │     Currencies       │   │
  │Received   Established│   │
  │EMP    B   EMP      C │   │
  │DEPT   Y   DEPT     Z │   │
  │OFFICE M              │   │
  └──────────┬───────────┘   │
             │               │    DIALOG C returns control to
             └───────────────┘    DIALOG A:

                                  - Only currencies established
                                    by DIALOG A are available.
                                  - Record buffers still contain
                                    data established by DIALOG C

Effect of Control Commands on Issuing and Receiving Dialogs

The following table outlines the effect of control commands on issuing and receiving dialogs. The EXECUTE NEXT FUNCTION command is not included in this table. The characteristics established by EXECUTE NEXT FUNCTION depend on which command is actually executed.