DATABASE MANAGEMENT SYSTEM ARCHITECTURE
- 2. Data Models • Data Model – A collection of concepts that can be used to describe the structure of a database – By the structure we mean the data types, relationships, and constraints that should hold on the data – Also includes basic operations for specifying retrievals and updates on the database – It is becoming more common to include concepts to specify the dynamic aspect or behavior of a database application
- 3. Objectives • All users should be able to access same data. • A user’s view is immune to changes made in other views. • Users should not need to know physical database storage details.
- 4. • The logical DBMS architecture • The physical DBMS architecture DBMS ARCHITECTURE
- 5. • The logical DBMS architecture • The physical DBMS architecture DBMS ARCHITECTURE The logical architecture deals with the way data is stored and presented to users.
- 6. • The logical DBMS architecture • The physical DBMS architecture DBMS ARCHITECTURE The physical architecture is concerned with the s/w components that make up a DBMS.
- 7. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict.
- 8. 8 DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. DDL – set of commands required to define the format of data. DML – set of commands that modify, process data. DML precompiler 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.
- 9. 9 DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. DDL compiler 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.
- 10. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Manages the allocation of space on disk storage.
- 11. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Responsible for receiving query language statements and changing to a form the DBMS can understand. It has two parts : (i) parser (ii) query optimizer
- 12. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. It is the interface b/w low- level data, application programs and queries. It enforces constraints to maintain the consistency and integrity of the data as well as its security. It synchronizes the concurrent access. It also perform backup and recovery operations.
- 13. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager
- 14. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager Checks that the user has necessary authorization to carry out the required function.
- 15. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager Converts commands to a logical sequence of steps.
- 16. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager Checks the requested operation satisfies all necessary integrity constraints such as key constraints.
- 17. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager Examines the query language statements and tries to choose the best and most efficient way to executing the query. Factors – CPU time, disk time, network time, sorting methods and scanning methods.
- 18. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager The transaction manager maintains tables of authorization concurrency.
- 19. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager It controls the relative order in which transaction operations are executed.
- 20. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager Ensures that the database remains in a consistent state in the presence of failures. Responsible for transaction commit and abort.
- 21. DBMS Structure Object Code Of Program DML Precompiler Query Processor DDL Compiler Database Manager File Manager Database Schema System Calls Application Programs General users AP Query DBA Data Files Data Dict. Components • Authorization Control • Command Processor • Integrity Checker • Query Optimizer • Transaction Manager • Scheduler • Recovery Manager • Buffer Manager Responsible for the transfer of data between main memory and secondary storage.