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This article is about what relational operations are unique to relational databases. The editor thought it was very practical, so I shared it with you as a reference. Let's follow the editor and have a look.

The unique relational operations of relational database are: 1, selection operation, picking out those records that meet the specified conditions from all the records of the two-dimensional relational table; 2, projection operation, selecting some fields and their values from all fields for operation, it is a vertical operation; 3, join operation, the projection operation of the two relations to join to generate a new relationship.

Relational database system has three kinds of special relational operations.

1) selection operation: select those tuples that meet the qualification from a given relationship.

2) projection operation: select the specified attribute group from all the attributes of a given relationship in the desired order.

3) join operation: the attribute names of two different relations are spliced into a large relation schema, the attribute values with the same properties in the two relations should meet the qualified conditions, and the new tuples after these tuples are spliced together form the new relationship after the join.

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