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Boyce–Codd normal form. Not to be confused with Backus–Naur form. Boyce–Codd normal form (BCNF or 3.5NF) is a normal form used in database normalization. It is a slightly stricter version of the third normal form (3NF). By using BCNF, a database will remove all redundancies based on functional dependencies.
Codd went on to define the second normal form (2NF) and third normal form (3NF) in 1971, [5] and Codd and Raymond F. Boyce defined the Boyce–Codd normal form (BCNF) in 1974. [ 6 ] Informally, a relational database relation is often described as "normalized" if it meets third normal form. [ 7 ]
Boyce–Codd normal form (BCNF) was developed in 1974 by Boyce and Edgar F. Codd. It is a type of normal form that is used in database normalization. The goal of relational database design is to generate a set of database schemas that store information without unnecessary redundancy. Boyce-Codd accomplishes this and allows users to retrieve ...
Fourth normal form (4NF) is a normal form used in database normalization. Introduced by Ronald Fagin in 1977, 4NF is the next level of normalization after Boyce–Codd normal form (BCNF). Whereas the second, third, and Boyce–Codd normal forms are concerned with functional dependencies, 4NF is concerned with a more general type of dependency ...
The third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E. F. Codd in 1971. [2] Codd's definition states that a table is in 3NF if and only if both of the following conditions hold: The relation R (table) is in second normal form (2NF). No non-prime attribute of R is transitively dependent on ...
Second normal form (2NF), in database normalization, is a normal form. A relation is in the second normal form if it fulfills the following two requirements: It is in first normal form. It does not have any non-prime attribute that is functionally dependent on any proper subset of any candidate key of the relation (i.e. it lacks partial ...
3. Shop relation with attributes (ShopName (C), ShopType (B)) and PrimaryKey (ShopName (C)). Functional dependencies in this relation are: C → B. All these 3 relations are in BCNF and also the initial idea of functional dependencies is maintained (only slightly extended with the help of the transitive rule: AB → D, D → C lead to AB → C).
First normal form (1NF) is a property of a relation in a relational database. A relation is in first normal form if and only if no attribute domain has relations as elements. [1] Or more informally, that no table column can have tables as values. Database normalization is the process of representing a database in terms of relations in standard ...