Physical DBMS Architecture

  • Describes the software components used to enter and process data.
  • How these s/w components are related and interconnected.

Database Management System

  • Data Definition Language(DDL) - Set of commands required to define the format of data.
  • Data Manipulation Language(DML) - Set of commands that modify, process data.
  • DML Precompiler - It converts DML statements embedded in an application program to normal procedural calls in the host language. It interacts with the query processor in order to generate the appropriate code.
  • DDL Compiler - It converts DDL statements into a set of tables containing metadata tables which are in a form that can be used by other components of the DBMS. These are stored in system catalog or data dictionary.
  • File Manager - Manages the allocation of space on disk storage.
  • Query Processor - Responsible for receiving query language statements and changing to a form the DBMS can understand. It has two parts : parser and query optimizer.