Rename (relational algebra) (original) (raw)
In relational algebra, a rename is a unary operation written as where: * R is a relation * a and b are attribute names * b is an attribute of R The result is identical to R except that the b attribute in all tuples is renamed to a. For an example, consider the following invocation of ρ on an Employee relation and the result of that invocation: Formally, the semantics of the rename operator is defined as follows: where is defined as the tuple t, with the b attribute renamed to a, so that:
| Property | Value |
|---|---|
| dbo:abstract | In relational algebra, a rename is a unary operation written as where: * R is a relation * a and b are attribute names * b is an attribute of R The result is identical to R except that the b attribute in all tuples is renamed to a. For an example, consider the following invocation of ρ on an Employee relation and the result of that invocation: Formally, the semantics of the rename operator is defined as follows: where is defined as the tuple t, with the b attribute renamed to a, so that: (en) Na álgebra relacional, o operador de renomeação é utilizado para alterar o nome das colunas de uma tabela. Utilizado para relacionamentos onde possam surgir nomes iguais para as colunas, como num relacionamento da tabela com ela mesma. (pt) |
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| dbo:wikiPageWikiLink | dbr:Property dbr:Relation_(mathematics) dbr:Relational_algebra dbr:Unary_operation dbr:Tuple dbc:Relational_algebra |
| dbp:wikiPageUsesTemplate | dbt:Math dbt:Mvar dbt:Unreferenced |
| dct:subject | dbc:Relational_algebra |
| rdfs:comment | In relational algebra, a rename is a unary operation written as where: * R is a relation * a and b are attribute names * b is an attribute of R The result is identical to R except that the b attribute in all tuples is renamed to a. For an example, consider the following invocation of ρ on an Employee relation and the result of that invocation: Formally, the semantics of the rename operator is defined as follows: where is defined as the tuple t, with the b attribute renamed to a, so that: (en) Na álgebra relacional, o operador de renomeação é utilizado para alterar o nome das colunas de uma tabela. Utilizado para relacionamentos onde possam surgir nomes iguais para as colunas, como num relacionamento da tabela com ela mesma. (pt) |
| rdfs:label | Rename (relational algebra) (en) Renomear (álgebra relacional) (pt) |
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| foaf:isPrimaryTopicOf | wikipedia-en:Rename_(relational_algebra) |
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| is foaf:primaryTopic of | wikipedia-en:Rename_(relational_algebra) |