congenial
发表于 2025-3-25 05:49:00
e final result is an L-augmentation of the universal relation scheme and a lossless, γ-acyclic 4NF database scheme for the L-augmented relation scheme..This method can be specialized, such that the number of relation schemes in the database scheme is linear in the number of original attributes.
Legion
发表于 2025-3-25 09:40:41
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Generic-Drug
发表于 2025-3-25 12:38:36
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entitle
发表于 2025-3-25 18:13:04
Cornelia Geißlers, where some data items may be accessed by several read and write steps in an arbitrary fashion, and those involving nested transactions. The main graph-theoretic properties used in these characterizations are a directed cutset matching property and graph contraction.
amorphous
发表于 2025-3-25 21:48:27
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打击
发表于 2025-3-26 03:41:21
BG homomorphisms are studied in Sect. 5.2. Section 5.3 concerns relational structures and relational databases. It is especially shown that two fundamental problems dealing with conjunctive, positive and non-recursive queries—the query evaluation problem and the query containment problem—are equiva
燕麦
发表于 2025-3-26 07:39:30
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ethereal
发表于 2025-3-26 10:12:18
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cruise
发表于 2025-3-26 16:08:13
8楼
不发音
发表于 2025-3-26 20:20:10
8楼