What is the operation called to find tuples that satisfy a given condition from a relation in a relational database?

In a relational database, finding tuples that satisfy given conditions from a relationship is called selection. The condition is given as a logical expression, and the tuple with a true value will be selected.

#The operation of finding tuples that satisfy a given condition from a relationship is called selection. The conditions are given as logical expressions, and the tuples with true values ​​will be selected.

This operation extracts tuples from the horizontal direction. The phrases FOR and WHILE in FOXPRO are equivalent to selection operations.

In a relational database, there are three basic operations on relationships, which are:

1. Selection operation: the operation of finding tuples that meet given conditions from the relationship;

2. Projection operation: the operation of selecting several attributes from a relationship to form a new relationship;

3. Connection operation: the operation of merging two or more relationships into a new relationship based on the associated fields. .

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