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Used to specify database
retrievals and updates DML commands (data sublanguage) can be embedded in a
general-purpose programming language (host language), such as COBOL, C,
C++, or Java.
• A library of functions can also
be provided to access the DBMS from a programming language
• Alternatively, stand-alone DML
commands can be applied directly (called a query language).
Types of DML
• High Level or Non-procedural
Language:
For example, the SQL relational
language are “set”-oriented and specify what data to retrieve rather than how
to retrieve it. Also called declarative languages.
• Low Level or Procedural
Language: Retrieve data one record-at-a-time; Constructs such as looping
are needed to retrieve multiple records, along with
positioning pointers.
DBMS Interfaces
• Stand-alone query language
interfaces
Example: Entering SQL queries at
the DBMS interactive SQL interface (e.g.
SQL*Plus in ORACLE)
• Programmer interfaces for
embedding DML in programming languages
• User-friendly interfaces
• Menu-based, forms-based, graphics-based,
etc.
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