• Data-definition language (DDL)
–To specify the database schema
–The output of the DDL is placed in the data dictionary, which contains metadata
— that is, data about data.
• Data-manipulation language (DML)
–To express database queries and updates
• Retrieval of information stored in the database
• Insertion of new information into the database
• Deletion of information from the database
• Modification of information stored in the database