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What is bcnf explain with example?
define BCNF. Explain with appropriate example
What is the difference between 3NF and BCNF?
Boyce-codd normal form(BCNF) was proposed as a simpler form of 3NF,but it was found to be stricter than 3NF,because every relation in BCNF is also in 3NF.However a relation in 3NF is not necessarily in BCNF.
Boyce-Codd normal form BCNF?
Yes, acronym BCNF stands for 'Boyce-Codd Normal Form'.
What is overlapping key DBMS?
Overlapping Key is a type of candidate key which occurs in BCNF (Boyce –Codd Normal Form).In the difference between 3NF and BCNF Example : A 3NF table which does not have multiple overlapping candidate keys is guaranteed to be in BCNF. Depending on what its functional dependencies are, a 3NF table with two or more overlapping candidate keys may or may not be in BCNF.
Is a relation in bcnf always in 3nf?
Yes.
Why bcnf is stronger than 3nf?
A relation R is in 3NF if and only if every dependency A->B satisfied by R meets at least ONE of the following criteria: 1. A->B is trivial (i.e. B is a subset of A) 2. A is a superkey 3. B is a subset of a candidate key BCNF doesn't permit the third of these options. Therefore BCNF is said to be stronger than 3NF because 3NF permits some dependencies which BCNF does not.
Why 4NF is preferable then bcnf .with example?
Normalization is a process to reduce the redundancy by removing function dependencies BCNF (Boyece code normal form) has all functional dependencies A to B are trivial of discriminator should be superkey. To get relation in BCNF, Splitting the relation schema not neccessarily preserve all functional dependency, Loss less decomposition and dependency are main points for the normalization sometime, it is not possible to get a BCNF decomposition that is dependency, preserving. While 4NF has very similar definition as BCNF. A relational Schema is in 4NF, if all multivalued dependencies A to B are trivial and determinate A is superkey of schema. If a relational schema is in 4nf, it is already in BCNF. and 4NF decomposition preserve the all functional dependency. so 4NF is preferable than to have BCNF.
What is the differences between BCNF and 3NF in database?
3NF is where data depends on nothing but the whole key. It seems that every 3NF table should be in BCNF, as BCNF is stricter than 3NF. But, BCNF requires that every nontrivial attribute is a superkey, even if the dependent attributes are part of keys, that is, when X->Y, X is a superkey for the relation, where 3NF also allows that Y is a key attribute for the relation.
What is the difference between third normal form and bcnf?
Both 3NF and BCNF are normal forms that are used in relational databases to minimize redundancies in tables. In a table that is in the BCNF normal form, for every non-trivial functional dependency of the form A → B, A is a super-key whereas, a table that complies with 3NF should be in the 2NF, and every non-prime attribute should directly depend on every candidate key of that table. BCNF is considered as a stronger normal form than the 3NF and it was developed to capture some of the anomalies that could not be captured by 3NF. Obtaining a table that complies with the BCNF form will require decomposing a table that is in the 3NF. This decomposition will result in additional join operations (or Cartesian products) when executing queries. This will increase the computational time. On the other hand, the tables that comply with BCNF would have fewer redundancies than tables that only comply with 3NF. Furthermore, most of the time, it is possible to obtain a table that comply with 3NF without hindering dependency preservation and lossless joining. But this is not always possible with BCNF.
What is bcnf explain with respect to dbms?
Boyce -Codd normal form which is one of the forms of dbms noramlizations.normalization is converting the relations or tables in a standard form.bcnf is based on functional dependencies that take into account all candidate keys.a relation is in bcnf if every determinant has a candidate key..:)
What is bCnf in rdbms?
It is boyce-codd normal form IN NORMALIZATION WHICH SHOULD BE IN 3NF and EVERY DETERMINAT IS A CANDIDATE KEY .
Why 4NF is more desirable Normal Form than BCNF?
Because 4nf minimize the redundancy as well as make storage management..
