Which of the following statements about dependency preservation is true?Dependency preservation ensures that all relations are in 2nd Normal Form (2NF).It guarantees that no transitive dependencies exist in a relation.Dependency preservation is only relevant for relations with composite keys.It ensures that the decomposition of relations during normalization maintains the same functional dependencies.Next
Question
Which of the following statements about dependency preservation is true?Dependency preservation ensures that all relations are in 2nd Normal Form (2NF).It guarantees that no transitive dependencies exist in a relation.Dependency preservation is only relevant for relations with composite keys.It ensures that the decomposition of relations during normalization maintains the same functional dependencies.Next
Solution 1
The correct statement about dependency preservation is: "It ensures that the decomposition of relations during normalization maintains the same functional dependencies."
Dependency preservation is a property of database decomposition. It ensures that after decomposing a relation (table), all the functional dependencies of the original relation can still be enforced on the decomposed relations. This is important because it allows us to enforce constraints on the database schema without having to check the entire database.
The other statements are not correct. Dependency preservation does not ensure that all relations are in 2nd Normal Form (2NF), it does not guarantee that no transitive dependencies exist in a relation, and it is not only relevant for relations with composite keys.
Solution 2
The correct statement about dependency preservation is: "It ensures that the decomposition of relations during normalization maintains the same functional dependencies."
Dependency preservation is a property of database decomposition. It ensures that after decomposing a relation (table), all the functional dependencies of the original relation can still be enforced on the decomposed relations. This is important because it allows us to enforce constraints on the database schema without having to check the entire database.
The other statements are not correct. Dependency preservation does not ensure that all relations are in 2nd Normal Form (2NF), it does not guarantee that no transitive dependencies exist in a relation, and it is not only relevant for relations with composite keys.
Similar Questions
What does dependency preservation refer to in the database normalization?Ensuring that all functional dependencies are maintained during the normalization processEliminating all functional dependencies to simplify the database structureMinimizing data redundancy by organizing data into tables and columnsEnsuring that all relations are in Boyce-Codd Normal Form (BCNF)Next
Properties of RelationalDecompositions (3) Dependency Preservation Property of aDecomposition: Definition: Given a set of dependencies F on R,the projection of F on Ri, denoted by Ri(F) whereRi is a subset of R, is the set of dependenciesX Y in F+ such that the attributes in X υ Y are allcontained in Ri. Hence, the projection of F on each relationschema Ri in the decomposition D is the set offunctional dependencies in F+, the closure of F,such that all their left- and right-hand-sideattributes are in Ri.
When is a relation considered to be in second normal form (2NF)? (Select the best answer.)Select one:a.When there are no repeating groups in a relationb.When there are no transitive functional dependenciesc.When there are no dependencies on part of the primary keyd.When there are no dependent attributes in transitive relation
Which one of the following statements about normal forms is FALSE? (PERSISTENT)Options: Pick one correct answer from belowLossless, dependency -preserving decomposition into 3 NF is always possibleBCNF is stricter than 3 NFLoss less, dependency – preserving decomposition into BCNF is always possibleAny relation with two attributes is BCNF
Which statement best describes the purpose of Second Normal Form (2NF)?a.2NF allows redundancy to be eliminated completely from the relationb.2NF allows for the nesting of relations within relations, enhancing data organizationc.2NF ensures that every non-prime attribute is fully functionally dependent on the entire candidate key, thus removing partial functional dependenciesd.2NF ensures that every attribute in the relation is functionally dependent on the primary key
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