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| Advanced Topics |
Adding an ADABAS Observation
Adding ADABAS data as a result of update operations from various SAS procedures might cause the interface view engine to decide whether to add a new logical record to the ADABAS file or modify an existing logical record, for example, add an occurrence to a periodic group. The purpose of the engine making this determination is to reduce data redundancy.
The engine compares values in the new observation to be added to values in the previous observation. If the contents of the previous observation do not help determine whether to add or modify, a new logical record is added.
However, some of the new values might already reside in the ADABAS file, so a new record is not necessary. This situation occurs if a periodic group is included in a view descriptor, and the new data (which does not reside in the ADABAS file) occurs only in variables corresponding to data fields that are part of that periodic group.
The interface view engine can determine whether this situation exists. If not, a new logical record can be added. If so, an existing record can be modified. The optional BY key specification makes this possible. See Using a BY Key to Resolve Ambiguous Inserts.
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