WebNov 27, 2015 · If we go through all the FD's and none of the rows of our table get completely filled with a then it is a lossy decomposition. Also, note if it is a lossy decomposition we can always make it lossless by adding one more relation to our set of decomposed relations consisting of all attributes of the primary key. WebJan 14, 2024 · Lossless Decomposition: for a Decomposition of two Relation, R 1 and R 2 to be lossless 2 condition needs to be satisfied that is 1. R 1 ∩ R 2 → R 1 or R 2 i.e. common attributes must be key to either of the relation. 2. attributes of R 1 ∪ attributes of R 2 ≡ attributes of R Explanation: D1 : R = [ (P, Q, S, T); (P, T, X); (Q, Y); (Y, Z, W)]
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WebJun 28, 2024 · (A) A->B, B->CD (B) A->B, B->C, C->D (C) AB->C, C->AD (D) A ->BCD Answer: (C) Explanation: Background : Lossless-Join Decomposition: Decomposition of R into R1 and R2 is a lossless-join decomposition if at least one of the following functional dependencies are in F+ (Closure of functional dependencies) R1 ∩ R2 → R1 OR R1 ∩ R2 → R2 WebDecomposition in DBMS means dividing one table into multiple tables to remove redundancies and anomalies from a database. There are two types of decomposition: Lossy Decomposition; Lossless Decomposition; Lossy Decomposition: A decomposition is said to be lossy if a table is broken down into two tables and we do not get the same table when … grady-white 456
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Weblossless decomposition tutorial with example WebAug 21, 2024 · If the join of R1 and R2 over S is equal to relation R then we can say that a join dependency exists, where R1 and R2 are the decomposition R1 (P, Q, S) and R2 (Q, T) of a given relation R (P, Q, S, T). As a possibility, R1 and R2 are a lossless decomposition of R. WebDetermining Whether Decomposition Is Lossless Or Lossy-. Consider a relation R is decomposed into two sub relations R 1 and R 2. Then, If all the following conditions … china air business