Relational data languages include: relational algebra language, relational calculus language, and SQL.
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Features:
Relational algebra language: Use operations on relationships to express query requirements.
Relational calculus language: Use predicates to express query requirements.
Structured Query Language (SQL): It is a relational data language that integrates query, data definition language, data manipulation language, and data control language. It is a highly procedural language.
The common feature of these relational data languages is that the language has complete expression capabilities, is a non-procedural set operation language, has strong functions, and can be embedded in high-level languages.
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