Concept of Normalization
Normalization is the process of the splitting table to minimize data redundancy and establishing a relationship between tables. It is must be carefully designed in order to get full advantages It provides flexible, data consistency and avoids anomalies while inserting, deleting and updating data.
Forms of Normalization
There are six normal Forms but in practice first, second, and third normal forms are widely used.
1. First Normal Forms (1Ne): –Â A table is said to be in first normal form if it has no repeating groups. That is for each cell in a table, there can be only one value. It is flexible to handle one to many relationships, less space.
2. Second Normal Form (2Ne): –Â A table said to be in second normal form if it is already in first normal form and if every non-key column depends on the entire key.
3. Third Normal Form (3Ne): –Â A table is said to be in third normal form if it is already in second normal form and if non-key columns are not dependent on each other.
Types of Database
1) Centralized Database: Centralized Database works on a client sever basis. The Consoling mechanism is also centralized and data are deposited in a central location. Files kept on the basis location of disk drive & names. It is suitable for a small organization and small scale operations.
Advantage: – Easy to maintainDisadvantage: – If the server is destroyed by some catastrophic damage like flood fire whole data is lost.
2) Distributed Database: –Â Distributed database is dispersed across many geographical locations. Data communication is harder because they should communicate through a different system to the security of the different platform is the most crucial part of this database.
3) The distributed system offers a lot of advantages
- A distributed system is much cheaper than a centralized system less expensive hardware is used.
- It allows us to store copies of data at a different location.
- In a distributed system, the problem in one location will not affect the entire system.
Data security: –Â Data security is an important issue in every organization, big or small for maintaining database system data security is a method of keeping data protected from corruption and unauthorized access and ensuring privacy.
Two methods of data security
- Physical Security: –Â Physical security is concerned with physical aspects such as protecting computer resources preparing for physical disasters of catastrophic damage.
- Logical Security: –Â Logical security is concerned with protecting the data and controlling access to data.
Advantage of DBMS
- Data sharing: This is the most importance and biggest benefit all authorized user can work with the same set of data.
- Reduced Data redundancy: Data redundancy means that same data fields show in May different files and often in different formats.
- Improved Data Integrity: Data integrity means that data accurate consistent and up to date. In a DBMS reduced redundancy increase data integrity.
- Increased Security: Various departments may share data; access to specific information can be limited to selected users.