• DDL is used to define schemas, the storage structure, the integrity constraints and Authorizations on the database content and operations.

  • Specification notation for defining the database schema

  • Example: create table account ( account-number char(10), balance integer)

  • DDL compiler generates a set of tables which are stored in a data dictionary.

  • Data dictionary contains metadata (i.e., data about data)

    • Database schema
    • Storage structure and supported access methods
      • Specified using a data storage and definition language
    • Integrity constraints
      • Domain constraints
      • Referential integrity (references constraint in SQL)
      • Assertions

  • Authorization

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