The DBMS database management system application is partition into two and three parts. It is two-tier architecture, the application is categorized into the functionality at the server Machine through query language statement. Application program interface (API) like ODBC and JDBC is used for interactions between the different client and the server.
- Two – Tier architecture
- Three – Tier architecture
(a) Two – tier architecture-
user———– application( client)
(server)——– Network——– database system-
(b) Three – Tier architecture-
User———–application client———network—– —- application server—— Data base system.
In contrast, in the a three- tier architecture, the client machine act as merely a front end and does not contain any direct Database calls. Instead, the client end communication with an application server through a forms interface. The application server in turn communication with the database systems to access data. The business logic of application, which says what action to carry out under what conditions,is embedded in the application server, instead of being distributed across multiple clients. Three- Tier architecture application are more appropriate for large application,and for application that run on the world wide web WWW.
In the DBMS Data base management system is a partition into the module that deal with each of the responsibility of the overall system. The functional components of the database systems can be divided into the storage manager and the query processors.
The query processors-
- DDL interpreter-
- DML compilers-
- DML precompiler-
- Query Evaluation Engine-
Storage Manager- a storage manager is a program modules that provides the interface between the low- level data store in the database and application program and the queries submit to the system.
The storage manager components are as follows-
- Authorization and integrity manager-
- Transaction manager-
- Buffer manager-
- File manager-
The storage manager implementation several other Data structure are needed as the part of physical System implementation.
- Statistics Data
- Data file
- Data dictionary.
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