Copyright © TIBCO Software Inc. All Rights Reserved
Copyright © TIBCO Software Inc. All Rights Reserved


Chapter 4 Processing Data : GET Processing

GET Processing
A GET statement retrieves the first occurrence in the IDM table that satisfies the specified selection criteria.
A GET...ORDERED statement must retrieve all CA‑IDMS data that satisfies the selection criteria and SORT it in the Execution Environment before returning the first occurrence that meets the selection criteria.
The first record defined in the access path is retrieved from CA‑IDMS based on the selection criteria and whether the table is parameterized. The remaining records defined in the access path are retrieved from CA‑IDMS based on the set specified in the table definition and on selection criteria specified for elements of the remaining records.
Retrieving the First Record Defined in an Unparameterized Table
The first record defined in the access path of a non-parameterized table is retrieved as described in the following table:
Equality operator specified on a CALC key element that is defined as the TIBCO Object Service Broker primary key.
OBTAIN FIRST IN SET or OBTAIN FIRST IN AREA.
>, <, >=, or <= operators specified on a sort key element or on part of a composite sort key
Equality operator specified on part of a composite sort key or index
Position within the index or set and walk the index or set until the first record occurrence that satisfies the selection criteria is found.
Selection criteria specified on an element that is not a sort key or index
Selection criteria specified on a CALC key that is not defined as the TIBCO Object Service Broker primary key
Walk the set or sweep the area until the first record occurrence that satisfies the selection criteria is found.
When selection criteria are specified for both non-key IDMS/DB elements and IDMS/DB key elements (that is, CALC, sort key, and index elements), the Gateway does the following:
Retrieving the First Record in a Parameterized Table
A GET request on a parameterized table always results in an OBTAIN CALC request being sent to CA‑IDMS to access the first record defined in the IDM table definition.
Retrieving Remaining Parameterized Table Records
The remaining member records defined in the access path are retrieved as described in the following table for both non-parameterized and parameterized tables:
Walk the set until the first record occurrence that satisfies the selection criteria is found.
>, <, >=, or <= operators specified on a sort key element or part of a composite sort key.
Position within the set and walk the set until the first record occurrence that satisfies the selection criteria is found.
When selection criteria are specified for both IDMS/DB sort key elements and non-key IDMS/DB elements, the Gateway does the following:
If more than one set is included in the access path, the Gateway positions itself within each set, where possible, based on the points outlined in the above table.
Remaining owner records defined in the access path for both non-parameterized and parameterized tables are retrieved with an OBTAIN OWNER request using the specified set name. Selection criteria specified on elements of the owner record are evaluated after the owner is retrieved.

Copyright © TIBCO Software Inc. All Rights Reserved
Copyright © TIBCO Software Inc. All Rights Reserved