15/5/13
(WEDNESDAY)
Today we had learn about data management. The purpose of data management of resources is to have a systematic , no duplication and easy to retrieve information. Well manage, carefully arranged files make it easy to obtain data. Meanwhile, poorly managed files lead to chaos in information processing , high costs, poor performance.
Problems With Traditional File Environment
1) Data redundancy & confusion
2) program data dependence
3) Lack of flexibility
4) poor security
5) lack data sharing and availability
DBMS
DBMS = database management system (database software)
is the type of program used to create , maintain, and organise data in a database, as well as to retrieve information from it.
a) advantages of DBMS
1) Complexity of system can be reduce
2) Data redundancy & inconsistency can be reduced
3) Data confusion can be eliminated
4) program development & maintenance can radically reduced
5) flexibility of information system can be greatly enhanced
6) Access and availability of information can be increased
7) reduction of duplication
8) improved data integrity
9) programs are independent of the data format
10) sharing of data resources
Disadvantages of DBMS
1) Added expense
2) More hardware may be needed
3) additional training
4) security critical
5) sophisticated design and programming required
Designing Databases
Logical databases modes for keeping track of entities, attributes and relationships. There are three principal logical databases models are Hierarchical, network and relational.
Problems With Traditional File Environment
1) Data redundancy & confusion
2) program data dependence
3) Lack of flexibility
4) poor security
5) lack data sharing and availability
DBMS
DBMS = database management system (database software)
is the type of program used to create , maintain, and organise data in a database, as well as to retrieve information from it.
a) advantages of DBMS
1) Complexity of system can be reduce
2) Data redundancy & inconsistency can be reduced
3) Data confusion can be eliminated
4) program development & maintenance can radically reduced
5) flexibility of information system can be greatly enhanced
6) Access and availability of information can be increased
7) reduction of duplication
8) improved data integrity
9) programs are independent of the data format
10) sharing of data resources
Disadvantages of DBMS
1) Added expense
2) More hardware may be needed
3) additional training
4) security critical
5) sophisticated design and programming required
Designing Databases
Logical databases modes for keeping track of entities, attributes and relationships. There are three principal logical databases models are Hierarchical, network and relational.
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| Hierarchical data model |
 | ||
| Network Data Model |
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| Relational data model |
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