Wikipedia

• Category:Mathematical relations
• Relation (mathematics) a binary relation on a set may, or may not, hold between two given set members.
• Relational model is an approach to managing data using a structure and language consistent with first-order predicate logic
• Category:Relational model
• Relationalism things exist and function only as relational entities
• List of relational database management systems
• Comparison of relational database management systems
• Relational calculus consists of two calculi, the tuple relational calculus and the domain relational calculus, that is part of the relational model for databases and provide a declarative way to specify database queries.
• Tuple relational calculus a declarative database-query language for data manipulation in this data model.
• Domain relational calculus a declarative database query language for the relational data model.
• Algebraic logic is the reasoning obtained by manipulating equations with free variables.
  • Calculus of relations
• Relational algebra is a theory that uses algebraic structures for modeling data, and defining queries on it with a well founded semantics.
• Category:Relational algebra
• Order theory investigates the intuitive notion of order using binary relations.