Normalization to Database
NORMALIZATION OF DATABASE
NORMALIZATION- is the process for evaluating and correcting table structures to minimize data redundancies, thereby, reducing the livelihood of data anomalies.
The normalization process involves assigning attributes to tables based on the concept of determination.
Normalization works through a series of stages called normal forms.
3 Stages of Normalization 1. 1NF or FIRST NORMALIZATION FORM 2. 2NF or SECOND NORMALIZATION FORM 3. 3NF or THIRED NORMALIZATION FORM
Although normalization is a very important database design ingredient, you should not assume that the highest level of normalization is always the most desirable. Generally, the higher normal form, the more relational join operations required to produce a specified output and the more resources by the database system to respond to end-user queries. A successful design must also consider end-user demand for fast performance.
THE NORMALIZATION PROCESS
The objective is to create tables that have the ff. characteristics. 1. Each table represents a single subject. For example, a COURSE table will contains only data that directly pertains to courses. Similarity, a STUDENT table will contain only student data. 2. No data item will be unnecessarily stored in more than one table. The reason for this requirement is to ensure that the data are updated in only one place. 3. All attributes in a table are dependent on the primary key and nothing but the primary key.
* REPEATING GROUP-derives its name from the fact that a group of multiple entries of the same type can exist for any single key attribute occurrence. * Normalizing the table structure will reduce the data redundancies.
CONVERSION TO FIRST NORMAL FORM
Step 1: Eliminate the Repeating Groups
Step 2: Identify the Primary Key
Step 3: Identify All Dependencies
CONVERSION TO SECOND NORMAL FORM
The relational database design can be improved easily by converting the database into a format known
NORMALIZATION- is the process for evaluating and correcting table structures to minimize data redundancies, thereby, reducing the livelihood of data anomalies.
The normalization process involves assigning attributes to tables based on the concept of determination.
Normalization works through a series of stages called normal forms.
3 Stages of Normalization 1. 1NF or FIRST NORMALIZATION FORM 2. 2NF or SECOND NORMALIZATION FORM 3. 3NF or THIRED NORMALIZATION FORM
Although normalization is a very important database design ingredient, you should not assume that the highest level of normalization is always the most desirable. Generally, the higher normal form, the more relational join operations required to produce a specified output and the more resources by the database system to respond to end-user queries. A successful design must also consider end-user demand for fast performance.
THE NORMALIZATION PROCESS
The objective is to create tables that have the ff. characteristics. 1. Each table represents a single subject. For example, a COURSE table will contains only data that directly pertains to courses. Similarity, a STUDENT table will contain only student data. 2. No data item will be unnecessarily stored in more than one table. The reason for this requirement is to ensure that the data are updated in only one place. 3. All attributes in a table are dependent on the primary key and nothing but the primary key.
* REPEATING GROUP-derives its name from the fact that a group of multiple entries of the same type can exist for any single key attribute occurrence. * Normalizing the table structure will reduce the data redundancies.
CONVERSION TO FIRST NORMAL FORM
Step 1: Eliminate the Repeating Groups
Step 2: Identify the Primary Key
Step 3: Identify All Dependencies
CONVERSION TO SECOND NORMAL FORM
The relational database design can be improved easily by converting the database into a format known