To enable use of LRF, DBAs predefine the paths that a dialog can use to access specific views of data in the database. Logic to navigate the database is contained in the path definition.
Given the dialog's data requirements, the programmer selects the appropriate LRF path and then codes database requests in the form of LRF commands within the dialog's process logic. At runtime, CA IDMS/DB locates the requested data using the specified path.
Components of LRF
LRF processes commands associated with logical records. When a dialog issues an LRF command, LRF selects an appropriate path based on the information in the command statement. LRF uses field values in the record buffer that is established for the logical record to update the database.
Logical records are defined in a subschema by the database administrator (DBA). Each logical record is composed of fields selected from one or more subschema records or roles that are typically accessed together.
Logical Record Facility paths are also defined in the subschema. Each path is a group of database access instructions that perform the processing necessary to satisfy an LRF request. One or more paths are associated with each logical record in the subschema.
The predefined conditions affecting logical record access include:
To use Logical Record Facility commands effectively, the application developer must be familiar with the processing characteristics of the logical records that are defined in the subschema.
Note: For more information about using Logical Record Facility, see the CA IDMS Logical Record Facility.
Process code within a single dialog cannot reference more than one logical record that includes fields from a given subschema record.
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