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Which of the following relation schema is always in BCNF?
A relational schema R is in BCNF form if and only if for every one of its dependencies X → Y, at least one of the following conditions hold : 1. X → Y is a trivial functional dependency i.e. Y is a subset of X . So, we check transitive dependency for only non-prime attributes in case of BCNF.
Which one is not functional dependency?
Non Trivial Functional Dependency in DBMS In a relationship, if attribute B is not a subset of attribute A, then it is considered as a non-trivial dependency. But CEO is not a subset of Company, and hence it’s non-trivial functional dependency.
How is every binary relation ( BCNF ) normalized?
Your relation must have at least one candidate key (that is, you can’t have repeating rows in the relation), else it wouldn’t even meet the conditions for 1NF. Given this, your relation can have zero, one or two FDs. The case for zero FDs is trivial (ab->ab). For one FD (a->b) the left hand side attribute is clearly the key.
When does a relation have to be in BCNF?
A relation is in BCNF when, for all FDs that apply to the relation, the left hand side is a superkey. That is, it has to contain all the attributes of at least one key. Your relation must have at least one candidate key (that is, you can’t have repeating rows in the relation), else it wouldn’t even meet the conditions for 1NF.
Which is a stronger variation of BCNF, 2NF or 3NF?
If a relation is in BCNF, it will satisfy 1NF, 2NF, and 3NF by default. It ensures that for every functional dependency X->Y, X is a super key of the table, making BCNF a stronger variation of 3NF. This is a guide to BCNF. Here we discuss BCNF and how it works, decomposition, advantages, and examples of BCNF.
How is Boyce Codd normal form ( BCNF ) different from 3NF?
Boyce–Codd Normal Form (BCNF) is based on functional dependencies that take into account all candidate keys in a relation; however, BCNF also has additional constraints compared with the general definition of 3NF. A relation is in BCNF iff, X is superkey for every functional dependency (FD) X→Y in given relation.