Database Design

Database design
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Before we talk about database design let’s understand first what a database is.

A database is a collection of data for one or multiple usage in a digital form. Here we can take as example in a company, the way they collect all the workers information, name, address, salary,  etc… or the our common used facebook, the way our name, password, information, friends, pictures, videos and so on are saved. It needs a huge place and couldn’t be saved in a computer’s hard disk, so the database will be used to save all those information

Database design: A database design is a data structure to design data model of a database.

The designer must determine:
    - The relationship between different elements
    - Superimpose a logical structure upon the data on the basis of these relationships.

Of course in a design, there is always a process and generally for big project the design is done by a person with expertise in the database design. The design process of a database is:

    - Determine the purpose of your database: In this case we have to be conscientious of the purpose of the database so that it will help on the remaining steps ;
    - Find and organize the information required: Here we have to know which information will need to be saved , what will be the relation with other objects and the size of each one ;
    - Divide the information into tables: In this step, we will put information into subject and each subject will become a table, it is for example a product and the client;
    - Turn information items into columns: Of course each table will have characteristics like the name of the product, it’s number, etc…;
    - Specify primary keys: In each table it must be a primary key which will define the whole row;
    - Setup the table relationship: After creating tables, we will think about the relationship between them;
    - Refine your design: It is for sure that after all these steps we will need to change some details, or look for some errors, and that will be in this step that we will make changes;
    - Apply the normalization: Apply the normalization rules to see if the tables are structured correctly.

The database design has different type, there are:
    - Conceptual schema;
    - Logically structuring data;
    - Physical database design

Here are some vocabularies about the database:
   DBMS: Database Management System
    ER Diagram: Entity-relationship model