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  2. First normal form - Wikipedia

    en.wikipedia.org/wiki/First_normal_form

    SQL-92 does not support creating or using table-valued columns, which means that using only the "traditional relational database features" (excluding extensions even if they were later standardized) most relational databases will be in first normal form by necessity. Database systems which do not require first normal form are often called NoSQL ...

  3. Database normalization - Wikipedia

    en.wikipedia.org/wiki/Database_normalization

    Database normalization is the process of structuring a relational database in accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity. It was first proposed by British computer scientist Edgar F. Codd as part of his relational model .

  4. Relational model - Wikipedia

    en.wikipedia.org/wiki/Relational_model

    A database that is in the first normal form is vulnerable to all types of anomalies, while a database that is in the domain/key normal form has no modification anomalies. Normal forms are hierarchical in nature. That is, the lowest level is the first normal form, and the database cannot meet the requirements for higher level normal forms ...

  5. Edgar F. Codd - Wikipedia

    en.wikipedia.org/wiki/Edgar_F._Codd

    Edgar Frank "Ted" Codd (19 August 1923 – 18 April 2003) was a British computer scientist who, while working for IBM, invented the relational model for database management, the theoretical basis for relational databases and relational database management systems.

  6. Category:Database normalization - Wikipedia

    en.wikipedia.org/.../Category:Database_normalization

    Pages in category "Database normalization" The following 22 pages are in this category, out of 22 total. ... First normal form; Second normal form;

  7. Unnormalized form - Wikipedia

    en.wikipedia.org/wiki/Unnormalized_form

    In database normalization, unnormalized form (UNF or 0NF), also known as an unnormalized relation or non-first normal form (N1NF or NF 2), [1] is a database data model (organization of data in a database) which does not meet any of the conditions of database normalization defined by the relational model.

  8. Conjunctive query - Wikipedia

    en.wikipedia.org/wiki/Conjunctive_Query

    In database theory, a conjunctive query is a restricted form of first-order queries using the logical conjunction operator. Many first-order queries can be written as conjunctive queries. In particular, a large part of queries issued on relational databases can be expressed in this way.

  9. Domain-key normal form - Wikipedia

    en.wikipedia.org/wiki/Domain-key_normal_form

    Domain-key normal form (DK/NF or DKNF) is a normal form used in database normalization which requires that the database contains no constraints other than domain constraints and key constraints. A domain constraint specifies the permissible values for a given attribute, while a key constraint specifies the attributes that uniquely identify a ...