6 Steps to Design a Database
Interestingly, when designing a database, much of the hard work is in the planning stages long before physically working with a database management system (DBMS). Attempting to implement a physical design without considering the prerequisite steps will cause on to repeat steps unnecessarily in the end. Each step listed below is necessary for achieving a secure and efficient database that meets the needs of its users with minimal to no issues.
Step 1: Requirements Analysis
In the first step, it is most important to gather all the project details. Start with a list of data. You will want to know what data will need to be stored and the expected operations and requirements. There aren't many restrictions in this step. Consider the entire process of designing a database as a funnel. This step is the top of the funnel, the widest part. Here, you get to be as creative as possible, and you'll want to be as thorough too because going back to add functions later will require more work. this is the best time to consider all the possibilities. Take your time during this step as you will find that it is best to do it right the first time.
Step 2: Conceptual Database Design
At this stage, the goal is to describe the primary data entities, attributes, and relationships; to provide an organized view of the relationships between each concept. This design is written or illustrated and occurs before actually using a DBMS. You will identify what reports and queries the end-user will need to generate. Assuming there is a current system already in place, take note of its capabilities and decide what additional functions are necessary.
You will also gather data on the user in this step. You will need to know exactly who will be using the data, how the data will be used, and if there will be multiple end-user data views. You will identify the sources of the data. It is important to recognize all the relationships between the data, the volume of data, and the frequency at which the data is used. This step is where the database designer and the end-user collaborate to discuss the specifics of what will appear in the end-user view(s).
Step 3: Logical Database Design
In this step of designing a database, it's time to decide how to arrange the attributes of the entities, separating them using tables, which can be completed manually using pen and paper or by using a design tool. The goal here is to create organized tables to make it easier to view data. Each table stores data pertaining to the entities in a way that eliminates repeated data (redundancies). This step is still more conceptual than the physical database design. During this phase of the design process, there is no physical implementation of the database just yet. Rather, you will arrange data in the most logical ways based on the relationships between the entities and the attributes within the entities. It is vital to allow for growth, scalability, and other changes as the user's needs may change over time. Focus on all of the requirements found in the previous steps and begin to piece it all together based on the end-user's needs.
Step 4: Schema Refinement
Simply put, schema refinement is a method of organizing data in the database. This is the time to look for potential problems in the original choice of schema and try to redesign. You will want to eliminate redundancies, anomalies, and unwanted characteristics during this step.
Step 5: Physical Database Design
The physical database design is the step where you will take all of the results from the previous processes and begin implementing your design into whichever DBMS you choose with the hopes of optimizing the performance. This is the part where all of your hard work comes together and can be tested. The main goals here are storing and retrieving data in the most effective way possible.
Step 6: Applications and Security Design
The final step in designing a database is testing how the newly created database interacts with surrounding applications. It is essential to keep the security of the data at the forefront. A well-designed database should be able to support the applications without issues of failing.
While we briefly discussed each step of the database design process, we will dive into each step in significantly more detail later in the series. Check back often to continue reading our Intro to Database Design Series. The next article focuses on identifying entities, identifying relationships, attributes, ERD, assigning keys, and important terms to know.