Language In use DBMS

Data Definition Language (DDL)
- Specification notation for defining the database schema
• E.g. create table account (account-number char(10),
balance integer)
- DDL compiler generates a set of tables stored in a data dictionary
- Data dictionary contains metadata (i.e., data about data) database schema
Data storage and definition language
• language in which the storage structure and access methods
used by the database system are specified
• Usually an extension of the data definition language

Data Manipulation Language (DML)
- Language for accessing and manipulating the data organized by the appropriate data model
• DML also known as query language
- Two classes of languages
• Procedural – user specifies what data is required and how to get those data
• Nonprocedural – user specifies what data is required without specifying how to get those data
- SQL is the most widely used query language

SQL
- Developed at IBM research labs at San Lose, Ca. in 1970’s
• D.Chamberlin was the leader in the research group
- Dominant data base language on mainframe computers, but available on mini and PC based DBMS
- ANSI (American National Standards Institute approved
in 1992 (SQL 92); SQL 93 exists but not popular