例句與造句

1. However Codd tables cannot represent the disjunction " result with possibly 0 or 1 rows ".
2. The " forgetful " nature of the two sub-queries was all that it took to guarantee that some sure information went unreported when the above query was run on the Codd table Emp.
3. Thus when unions are added to the query language, Codd tables are not even a weak representation system of missing information, meaning that queries over them don't even report all " sure " information.
4. The intuition for what happens above is that the Codd tables representing the projections in the subqueries lose track of the fact that the Nulls in the columns F12 . F2 and F23 . F2 are actually copies of the originals in the table J . This observation suggests that a relatively simple improvement of Codd tables ( which works correctly for this example ) would be to use " Skolem constants " ( meaning Skolem functions which are also constant functions ), say ? 12 and ? 22 instead of a single NULL symbol.
5. The intuition for what happens above is that the Codd tables representing the projections in the subqueries lose track of the fact that the Nulls in the columns F12 . F2 and F23 . F2 are actually copies of the originals in the table J . This observation suggests that a relatively simple improvement of Codd tables ( which works correctly for this example ) would be to use " Skolem constants " ( meaning Skolem functions which are also constant functions ), say ? 12 and ? 22 instead of a single NULL symbol.
6. It's difficult to find codd table in a sentence. 用codd table造句挺難的