Designing Dialogs › Design Considerations › Database, Work, and Map Records

Database, Work, and Map Records

At the beginning of each application thread, the CA ADS runtime system allocates a primary Record Buffer Block (RBB) and initializes a buffer in the RBB for each record associated with the top-level dialog.

Considerations

All lower-level dialogs can access records in any of the existing buffers, unless one of the following conditions is true:

• The dialog that receives control accesses a database record or a work record that has been assigned the NEW COPY attribute during dialog compilation.
• The dialog that receives control accesses a database record, work record, or logical record not used by a higher-level dialog.
• The dialog that receives control accesses a database record that uses a subschema not used by a higher-level dialog.

If one or more of these conditions exist, CA ADS allocates and initializes an additional buffer for the record.

Additional Buffers

Additional buffers are also allocated and initialized when one of the following situations exists:

• The record is assigned the WORK RECORD attribute during dialog compilation.
• The record is associated with the map used by the dialog.
• The record is named explicitly in a database command.

The following diagram shows the sequence in which CA ADS initializes record buffers as a series of dialogs receives control.

When dialog A begins executing, CA ADS allocates buffers for the EMPLOYEE and SKILL record types. Dialog B uses the previously allocated EMPLOYEE record buffer, but requires a new buffer for the OFFICE record. Dialog C requests and receives a new copy of the EMPLOYEE record buffer, but uses the previously allocated SKILL record buffer. Dialog D requires new buffers for both the DEPARTMENT and JOB records. CA ADS allocates a secondary RBB to accommodate the DEPARTMENT record, but uses the remaining space in the primary RBB for the JOB record.