History of Database Architecture
It is very important to understand the architecture of database very well because
What are those different level where we see the data in a database
In order to make proper use of data and to design the database properly.
In the beginning data processing with the file processing environment was developed.
Drawback: realized when Applo Moon Landing Project generate the huge amount of data and no proper recourse was available to handle or process that data.
Solution: 1st database system was implemented name IMS.
IMS
1st database system.
IMS was based on hierarchical data model. Hierarchical data model support one to many relationship between entities.
Drawback: IMS is tree like structure database, so people start finding it hard to implement different applications in different situation.
Solution: IDS database system was implemented
IDS
IDS database system was based on Network data model.
IDS support many to many relationship.
After that the efforts was made to standardized the architecture of database.
CODASYL
Conference of Data System and Language committee appointed DBTG to make effort to standardized the database architecture.
In 1971, DBTG proposed Two Level Architecture.
Two Level Architecture
System View: Schema
It represent the view of whole organization database structure.
User View: Subschema
It represent the view of different user group.
DDL is used to define the schema and subschema.
ANSI
American National Standards Institute reject the recommendation of DBTG.
ANSI organized committee SPARC (Standard Planning and Requirement Committee) to suggest the architecture.
SPARC proposed Three Level Architecture