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Functional dependency — A functional dependency (FD) is a constraint between two sets of attributes in a relation from a database.Given a relation R , a set of attributes X in R is said to functionally determine another attribute Y , also in R , (written X → Y ) if and… … Wikipedia
Multivalued dependency — In database theory, multivalued dependency is a full constraint between two sets of attributes in a relation. In contrast to the functional dependency, the multivalued dependency requires that certain tuples be present in a relation. Therefore, a … Wikipedia
Database normalization — In the design of a relational database management system (RDBMS), the process of organizing data to minimize redundancy is called normalization. The goal of database normalization is to decompose relations with anomalies in order to produce… … Wikipedia
Relational model — The relational model for database management is a database model based on first order predicate logic, first formulated and proposed in 1969 by Edgar Codd. [ Derivability, Redundancy, and Consistency of Relations Stored in Large Data Banks , E.F … Wikipedia
Third normal form — The third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E.F. CoddCodd, E.F. Further Normalization of the Data Base Relational Model. (Presented at Courant Computer Science Symposia Series 6, Data … Wikipedia
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… … Wikipedia
Nontrivial — is the opposite of trivial. In contexts where trivial has a formal meaning, nontrivial is its antonym. It is a term common among communities of engineers and mathematicians, to indicate a statement or theorem that is not obvious or easy to prove … Wikipedia
Boyce-Codd normal form — (or BCNF) is a normal form used in database normalization. It is a slightly stronger version of the third normal form (3NF). A table is in Boyce Codd normal form if and only if, for every one of its non trivial functional dependencies X → Y , X… … Wikipedia
Abhängigkeitstreue — Funktionale Abhängigkeiten (Abk. FA, englisch functional dependency, FD) sind ein Konzept der relationalen Entwurfstheorie und bilden die Grundlage für die Normalisierung von Relationenschemata. Eine Relation wird durch Attribute definiert.… … Deutsch Wikipedia
Funktionale Abhängigkeit — Funktionale Abhängigkeiten (Abk. FA, englisch functional dependency, FD) sind ein Konzept der relationalen Entwurfstheorie und bilden die Grundlage für die Normalisierung von Relationenschemata. Eine Relation wird durch Attribute definiert.… … Deutsch Wikipedia
