superkey

superkey
Any set of attributes of a relation variable (relvar) that serve to identify a single tuple or row, no other tuple having the same value for every attribute in the set.

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  • Superkey — A superkey is defined in the relational model of database organization as a set of attributes of a relation variable (relvar) for which it holds that in all relations assigned to that variable there are no two distinct tuples (rows) that have the …   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

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  • 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

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  • Unique key — In relational database design, a unique key can uniquely identify each row in a table, and is closely related to the Superkey concept. A unique key comprises a single column or a set of columns. No two distinct rows in a table can have the same… …   Wikipedia

  • Database — A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports… …   Wikipedia

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