Database Access Commands › Navigational DML › READY

READY

Purpose

Overrides the usage mode specified in a dialog's subschema for one or more database areas.

Database areas are readied when a run unit begins (that is, immediately before the execution of the first database-access command issued by a process).

Syntax

►►─── READY ────┬─────────────┬─────┬─────────────────────────────────────────►
                ├─ area-name ─┤     └─ USAGE-MODE ──┬──────┬──────────────────
                └─ ALL ◄ ─────┘                     ├─ IS ─┤
                                                    └─ =  ─┘

 ►──────────────────────────────────────────────────┬─────────────────────────►◄
  ──┬─────┬─────────────┬────┬─ RETRIEVAL ◄ ─┬───┬──┘
    │     ├─ PROTECTED ─┤    └─ UPDATE ──────┘   │
    │     └─ EXCLUSIVE ─┘                        │
    │                                            │
    └─ NOREADY ──────────────────────────────────┘

Parameters

area-name

Readies the named area in the specified usage mode.

ALL

Readies all areas in the specified usage mode.

If neither area-name nor ALL is specified, all areas defined in the dialog's subschema are readied in the usage mode specified in the subschema.

USAGE-MODE

Specifies the usage mode in which the object areas are readied.

IS or = are optional keywords and have no effect on processing.

PROTECTED

Prevents concurrent update of the object areas.

EXCLUSIVE

Prevents concurrent use of the object areas.

If neither PROTECTED nor EXCLUSIVE is specified, the usage mode is qualified as shared.

RETRIEVAL

Readies the object areas for retrieval only.

RETRIEVAL is the default when neither RETRIEVAL or UPDATE is specified.

UPDATE

Readies the object areas for both retrieval and update.

NOREADY

Indicates that the area or areas named are not to be readied.

Usage

Overview of Usage Modes

Usage modes restrict runtime operations. Database areas can be readied in a retrieval or update usage mode.

• When an area is readied in a retrieval usage mode, the run unit cannot issue CONNECT, DISCONNECT, ERASE, MODIFY, or STORE commands for records in the area.
• When an area is readied in an update usage mode, the run unit can issue all database commands for records in the area.

Usage modes can be qualified as protected, exclusive, or shared.

• A database area readied in a protected retrieval or update usage mode cannot be updated by a concurrently executing run unit. A run unit cannot ready a database area in a protected usage mode if another run unit has readied the same area in an update usage mode.
• A database area readied in an exclusive retrieval or update usage mode cannot be used in any way by a concurrently executing run unit. A run unit cannot ready a database area in an exclusive usage mode if another run unit has readied the area in any usage mode.
• A database area readied in a shared retrieval or update usage mode can be accessed by multiple run units concurrently. If neither protected nor exclusive is specified, the usage mode is qualified as shared.

Considerations

• CA ADS automatically readies all areas defined in a dialog's subschema in the usage mode (if any) specified in the subschema, or in a shared retrieval usage mode, unless the NOREADY option is specified.
• If you add an area to a subschema with default usage mode with the FORCE option, this area is readied even if the dialog is not recompiled. However, we recommend not to perform this action for ADS applications that use extended run units.

  Note: For more information on the limitations of using the FORCE option with ADS dialogs, see the Area Statement section (in the Subschema Statements chapter) in the CA IDMS Database Administration Guide.

• If the same area is named in more than one READY command in a process, the usage mode specified by the last READY command coded in the process applies to the named area for the entire process.
• An area cannot be readied in an update usage mode if the area includes any records that participate in a set whose members or owner are in an area readied in a retrieval usage mode.
• If a READY command results in a usage mode conflict for an area, the dialog issuing the READY command is placed in a wait state until the area is available in the requested usage mode.

Example 1: Readying an Area

The following example illustrates the use of the READY command:

READY ORDOR-REGION
USAGE-MODE IS PROTECTED UPDATE.

Example 2: Specifying That an Area Not be Readied

The following example illustrates the use of the NOREADY option. In this example, the area CUSTOMER-REGION is readied in shared update while the area ORDOR-REGION is not readied.

READY CUSTOMER-REGION
USAGE-MODE IS SHARED UPDATE.
READY ORDOR-REGION
USAGE-MODE IS NOREADY.

More information:

CA ADS Runtime System