A database is a collection of interrelated data in an organized and structured way. DBMS means database management systems which is a Software or collection of programs that enables you to store, modify, and extract information from a database.
Basically there are three types of DBMS
1) Hierarchical DBMS
2) Network DBMS
3) Relational DBMS
In a hierarchical DBMS the data is organized in a tree-like structure also called a parent-child relationship. In hierarchical database a parent can have multiple children, but a child can only have one parent.
Network DBMS is similar to Hierarchical except a child can have more than one-parent. While conceptually simple this database structure can quickly become very complicated.
In a relational DBMS data is organized in the form of two dimensional tables where rows are called records and the columns are called fields.
In case of Hierarchical and Network DBMS the data is manipulated using macros and these are mostly implemented on main-frame computers.
Where as the RDBMS uses SQL (structured query language) for data manipulations. Oracle, Sybase and SQL server examples of RDBMS. Tables are linked together using a field that uniquely identifies each record this makes the database very effective and called Indexing.
The data redundancy is very high in case of Relational database which increases the size of the database and decreases the efficiency of the database while its almost absent in the other two database types. Also need to create Index tables to speed up the query process in case of RDBMS which increases the size of the database further and also requires data purging and Index management.
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