The Database Load Process

The process of loading data with the CA IDMS DLI Transparency load utility can involve up to six steps, as follows:
idms
The process of loading data with the CA IDMS DLI Transparency load utility can involve up to six steps, as follows:
Step
Process
1. Preload CALC processing
Calculates database pages for CALC records (DL/I root segments). The actual database load (Step 2) can also perform this operation, but it takes longer to do so. Pre-load CALC processing is optional and is provided only to improve loading performance.
If preload CALC processing is performed, the resulting data should then be sorted to produce the optimum database loading sequence.
2. Database load
Stores the DL/I data in the prepared CA IDMS/DB database. If the DL/I hierarchies involved do not contain logical relationships, this is the only step required to complete the load process.
If logical relationships do exist, you must perform Steps 3 through 6 to resolve the logical child/logical parent relationships. Logical relationships require special treatment for the following reasons:
The hierarchical nature of the DL/I data does not ensure that a logical parent will be stored before its logical child.
The logical parent concatenated keys are not always present in a logical child input record.
If the load utility encounters a logical relationship during the load, it creates logical parent and logical child workfile records and writes them to a separate workfile.
3. Workfile sort/merge
Sorts the workfile produced by Step 2 so that the logical child records appear in proper sequence under their associated logical parent records.
4. Prefix (concatenated key) resolution
Uses the sorted workfile from Step 3 as input. For each logical parent record in the workfile, it generates a correct prefix (concatenated key) for each associated logical child record.
5. Workfile hierarchical sort
Accepts the prefix-resolved workfile from Step 4 as input and sorts the logical child records back into the original hierarchical sequence.
6. Prefix update
Retrieves logical child records already stored in the CA IDMS/DB database (by Step 2 processing). Using the hierarchically sorted workfile from Step 5, it adds the correct prefix (concatenated key) to each logical child database record and connects it to its logical parent record. This step completes the processing for DL/I data that contains logical relationships.
Each of the steps in the database load process is described separately later in this section.