2. Features of a DBMS
The prime purpose of a relational database management system is to maintain data integrity. This means all the rules and relationships between data are consistent at all times.
But a good DBMS will have other features as well.
- A command language that allows you to create, delete and alter the database (data description language or DDL)
- A way of documenting all the internal structures that make up the database (data dictionary)
- A language to support the manipulation and processing of the data (data manipulation language)
- Support the ability to view the database from different viewpoints according to the requirements of the user
- Provide some level of security and access control to the data
The simplest RDBMS may be designed with a single user in mind e.g. the database is 'locked' until that person has finished with it. Such a RDBMS will only cost a few hundred pounds at most and will have only a basic capability.
On the other hand an enterprise level DBMS can support a huge number of simultaneous users with thousands of internal tables and complex 'roll back' capabilities should things go wrong.
Obviously this kind of system will cost thousands along with a need to have professional database administrators looking after it and database specialists to create complex queries for management and staff.
Challenge see if you can find out one extra fact on this topic that we haven't already told you
Click on this link: What is a RDBMS
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