Table1 has clustered PK A, 2 has clustered PK [A,B] and has a foreign key to table1. Both A and B are uniqueidentifiers and when table2 adds a record, B is always set to newid() so B is unique in table2. For each A value, there aren't more than 100 B values and generally less than 20 B values. Access comes from one A value in table1 to retreive all matching A values in table2. Anyway I was told A was a covering index value in table2. The structure makes very good sense, but after getting a different definition of what a covering index is, I looked it up on the web and the first description I heard isn't correct. So what IS this kind of structure called?
kplcjl 17 Junior Poster
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