The database is the set of a group of related data, stored on a storage medium, for ease of data management and processing speed to do the manipulation for certain activities. One model that can be used in the design of the database is Normalization Techniques. Normalization is a process to create data that is not normal to be normal. Form data that is not normal / raw data commonly referred to as unnormalized form. Some form of normalization is often used, namely:
a. 1NF / First Normal Form
First normal form is the normal form of any data that is formed in a flat file in a one record after another record, and the value of each field in the form of atomic value. There is no set of repeated attribute, or attribute-value dual (multivalue). Each field is only one sense, not a collection of words that have ambiguous meanings, only one meaning only, and not the fraction of words that mean the same.
b. 2NF / Second Normal Form
The second normal form is a form of data meeting the criteria of normal form. Not the key attributes must depend on the function key / primary key. So for the second normal form, must be specified key field. The key field must be unique and may represent another attribute that is a member.
c. 3NF Third Normal Form
To become the third normal form, then the relationship should be in second normal form, and all attribute instead of the primary does not have a transitive relationship. In other words, each key attributes must depend not only on the primary key and primary key to the whole.
The purpose of normalization is to avoid data inconsistency, and avoid redundancy of data. There are several terms used in the normalization process is as follows :
Entity or entities are people, places, events or concepts that the information recorded or stored.
Each entity has the attribute or the name to represent an entity as to describe the characteristics of an entity.
Field used to present an attribute of the record that indicates an item of data.
d. Record / tuple
Record is a collection of fields that make up a record, one record represents a single data or information data.
e. File / table
File is a collection of similar records that have the same length of element, attribute the same but different valuenya.
Database is a collection of files that have links between one file with another file so as to form a structure of data to inform a company or agency within certain limits.