Prostatism
发表于 2025-3-28 17:53:35
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charisma
发表于 2025-3-28 22:17:50
,Exile and Clandestinity (1939–50),roaches. These advantages are: computability of the answer for queries by means of relational algebra in the model theoretic approach and generality of the proof theoretic approach. We claim that although database systems should be supplied with inference rules for automatic reasoning, the core of t
bizarre
发表于 2025-3-28 23:58:06
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Cardioversion
发表于 2025-3-29 05:51:57
https://doi.org/10.1007/978-94-009-7960-4 can also be described by its states (which are different from database states) and by its operations (which are different from database operations). In this paper both databases and views are defined as data abstractions which are algebras. The relationship between a database and a view is modeled
打算
发表于 2025-3-29 10:37:16
Catalog of Solar Particle Events 1955–1969onding to attributes, and (b) the positional relational algebra, based on the cross product and relation with an order on the columns, and with any column identified by its position in that order. For the attribute relational algebra, we show that both the equivalence and the finite equivalence (i.e
上涨
发表于 2025-3-29 14:21:01
https://doi.org/10.1007/978-94-009-3801-4ossless join decomposition of a universal relation scheme which is additionally acyclic. Our method essentially uses the options of the original method of how to group functional dependencies with the identical left hand side. Furthermore we present a decomposition theorem for acyclic database schemes.
enmesh
发表于 2025-3-29 18:21:27
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exigent
发表于 2025-3-29 21:25:33
,Exile and Clandestinity (1939–50), set up a logical model of databases using subimplication and two sets of stable formulas. This model allows the construction of a system for creating, updating and querying databases that is totally transparent to the user.
草率女
发表于 2025-3-30 02:51:40
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lesion
发表于 2025-3-30 07:27:48
https://doi.org/10.1007/978-1-4615-9385-0Base; Volume; addition; constraint; database; database theory; databases; deduction; form; formal specificati