SAS/ACCESS Interface to SYSTEM 2000 Data Management Software: Reference

Inserting Data Records

Insertion of database records occurs as a result either of update operations from various SAS procedures or of database loading from the DBLOAD procedure. When you insert a new observation, it can cause the insertion of more than one SYSTEM 2000 database record. The number of inserts depends on how many levels are in the database and on a comparison between the data being inserted and the data in the last observation read, if any. During an insert operation, levels having data different from the prior observation, if any, result in a SYSTEM 2000 database record insertion.

You can perform inserts with SYSTEM 2000 software in two modes:

insert mode
optimized load mode.

For the DBLOAD procedure, you determine the mode with the S2KLOAD statement. You must use insert mode if you are loading new records into existing logical entries.

Either load mode can be used for the DBLOAD procedure when you are loading entire logical entries. Optimized load mode is more efficient than insert mode, but it has some restrictions:

Data must be sorted in data tree order prior to the load.
Entire logical entries are always inserted.
The number of inserts and the levels at which inserts are performed depend on the order of the data and on what fields change from observation to observation.
Your input cannot be a SYSTEM 2000 view in the same environment.

Note: During optimized load processing, your output database will be open in exclusive use mode with rollback disabled temporarily. [cautionend]

Insert mode is suitable for mass insertion of descendant records into existing logical entries with the DBLOAD procedure. Similar to load mode, the engine determines where the new records go, depending on the values of fields in the observation. When you insert an observation, the engine compares it to the prior observation. Depending on how many fields have changed, one or more records are inserted at the levels that have changed. Also, you can specify a BY key to help determine the point of insertion. BY keys are discussed in the next section.

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