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  2. Second normal form - Wikipedia

    en.wikipedia.org/wiki/Second_normal_form

    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: A relation is in the second normal form if it fulfills the following two requirements:

  3. Database normalization - Wikipedia

    en.wikipedia.org/wiki/Database_normalization

    The objectives of normalization beyond 1NF (first normal form) were stated by Codd as: To free the collection of relations from undesirable insertion, update and deletion dependencies. To reduce the need for restructuring the collection of relations, as new types of data are introduced, and thus increase the life span of application programs.

  4. First normal form - Wikipedia

    en.wikipedia.org/wiki/First_normal_form

    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.

  5. Denormalization - Wikipedia

    en.wikipedia.org/wiki/Denormalization

    Denormalization is a strategy used on a previously-normalized database to increase performance. In computing, denormalization is the process of trying to improve the read performance of a database, at the expense of losing some write performance, by adding redundant copies of data or by grouping data.

  6. Comparison of programming languages (object-oriented ...

    en.wikipedia.org/wiki/Comparison_of_programming...

    This comparison of programming languages compares how object-oriented programming languages such as C++, Java, Smalltalk, Object Pascal, Perl, Python, and others manipulate data structures. Object construction and destruction

  7. Third normal form - Wikipedia

    en.wikipedia.org/wiki/Third_normal_form

    every element of Y \ X, the set difference between Y and X, is a prime attribute (i.e., each attribute in Y \ X is contained in some candidate key). To rephrase Zaniolo's definition more simply, the relation is in 3NF if and only if for every non-trivial functional dependency X → Y, X is a superkey or Y \ X consists of prime attributes.

  8. 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.

  9. Talk:Database normalization - Wikipedia

    en.wikipedia.org/wiki/Talk:Database_normalization

    Even if you provide a mathematical definition of 1NF, being in 1NF will be independent from being in 2NF. The quote from the article is wrong if 1NF is included. 2NF and higher are defined mathematically, and these definitions are such that for each i > j > 1, every database in iNF is also in jNF. Hence, for all NFs above 1, the quote is correct.