InterviewSolution
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InterviewSolution
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Could You Go Over Again The Concept Of "forcing" Un-optimized Load For The Mapping Function, Respective To The Qvd? |
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Answer» MAPPING tables may be loaded from a QVD, but it must be an un-optimized load (this is SOMETIMES called “unwrapping”). MyMap: MAPPING LOAD F1, F2 FROM sometable.qvd (qvd); The above mapping table will be created but it will appear to be EMPTY when USED in MAP USING or Apply Map(). No error, just no resulting mapping. One workaround is to create a condition that will cause an un-optimized load. We want all the rows, so we create an always-true condition that will return all rows. MyMap: MAPPING LOAD F1, F2 FROM sometable.qvd (qvd) WHERE 1=1;MAPPING tables may be loaded from a QVD, but it must be an un-optimized load (this is sometimes called “unwrapping”). MyMap: MAPPING LOAD F1, F2 FROM sometable.qvd (qvd); The above mapping table will be created but it will appear to be empty when used in MAP USING or Apply Map(). No error, just no resulting mapping. One workaround is to create a condition that will cause an un-optimized load. We want all the rows, so we create an always-true condition that will return all rows. MyMap: |
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