Sunday, July 28, 2013

Tutorial of How to Make a Relational Database

This post maybe will be the last article that specifically discuss about relational database and RDBMS. It is about the tutorial of how to make a relational database. Previous article are about the differences between RDBMS and DBMS, the advantages and benefits, and also the disadvantages and weaknesses. I hope all of them will enrich our insight and knowledge.

How to Make a Relational Database

A relational database is a method of storing data in tables containing information grouped by entity or object which the data describes. Tables can be very general, encompassing a large variety of objects or very specific. A general table or entity about animals would have attributes or fields that tell you the type and breed. A more specific design might have a table for dogs, another for cats, etc. The database is called relational because each table can have relationships with other tables based on a shared piece of information. The relationship can be simply a reference or a parent/child association.
  1. List business processes. These are transactions that involve adding, updating or using data.
  2. Diagram each business process flow. Show each step in the process and what detailed information is passed to and from each step. Record all data elements in the form of what object they describe.
  3. Analyze information identified in the process flow diagrams and convert to entities. Entities are objects of importance to the business process, such as a customer or a product that you store information about. List attributes or data elements to be stored about each entity such as a customer address.
  4. Identify keys to each entity. Keys are unique identifiers that will isolate an instance of each entity such as a customer number or product code.
  5. Identify relationships between entities and how they reference each other. A customer order might be an entity that contains a product code that becomes the link to another entity.
  6. Define a database table for each entity. Attributes of the entity become fields and if a field is the key identifier to another entity it becomes a "Foreign Key" or referential constraint.
Tips & Warnings:
Build your design on paper first, then use spreadsheets to simulate the design and then define tables in the database. A prototype allows you to see possible changes before you start coding.

Source : Dennis Bortolus - eHow