What is the importance of using ERDs when designing databases? Are there any disadvantages to creating an ERD?

I think that ERD has two broad applications. One is to help you (correctly by the database developer) design correctly before starting to build database tables. The second is to help future database users explain how to organize the data and why it is in the requirements collection phase.

In my current position, I believe that my users are not very technical and can usually correct desktop design. It is common to create ERDs only for the initial purpose above. I rarely show the completed ERD to the end user because they do not get any benefit from experience. For the same reason, the ERD and ERD specifications seen in the database design course are similar to cocktail napkin sketches and building plan. I usually use Excel to list the tables and columns - draw an arrow between the primary key and the foreign key to show the relationship. This is usually enough so that you do not miss the tables, columns, or relationships that are needed for the application I'm designing.

The main drawback of creating an ERD is the time it takes to create. That is why I proceeded my way in my own way. ERD is basically useless when the database is created. They actually have the sole purpose at the design stage. It can be said that it can be used as a means to record the database. However, based on my experience - normal databases change over time. The field or table will be added later in the development phase or after the database operation begins (normally the user will review the new requirements only after starting to use the system). If used as a means of documentation unless you update the ERD back (more work), make changes after the design make the ERD useless (or at least misleading).

Database design - Depending on the scale of the change, it is dangerous to directly change the database structure with the DBMS. Please carefully plan the changes to prevent the data in the production database from being corrupted. ERD is a useful tool. Draw ER diagrams to visualize the idea of ​​database design to identify errors and design flaws and modify them before performing database changes. Debugging databases - Debugging database problems can be challenging, especially if there are many tables that need to write complex SQL in the database and retrieve the necessary information. Using the ERD visualization database schema you can see the overall picture of the database schema. You can easily find entities, look at their characteristics, and determine their relationship with others. All of this makes it easier to analyze existing databases and reveal database problems.

Today I will introduce all knowledge on ER diagram making. By reading this ERD guide, you can acquire basic knowledge and skills related to ER diagrams and database design. You learn what ERD is, why ERD is, ERD symbols, how to draw ERD, etc. There are many examples of ERD. Entity relationship diagram, also called ERD, ER diagram, or ER model, is a structural diagram for database design. ERD contains a variety of symbols and connectors that visualize two important pieces of information. The main entity in the system and the interrelationship between these entities.