Author: Zen and the Art of Computer Programming
1 Introduction
In large projects, the code base is getting larger and larger, and the problem of database table structure inconsistency between different modules in the project often occurs. In order to solve this problem, engineers will use Data Definition Language (DDL) to define the database table structure, which will ensure the consistency, integrity and maintainability of the database table structure. However, if the database table structure designer does not use a standardized method to create the table structure, it may cause problems with the relationships between tables. For relational databases, there is a mechanism called constraints that can be used to detect and ensure the correctness of the table structure, such as unique key constraints, foreign key constraints, etc. Therefore, if the designer can design the table to be more standardized and use checker tools to ensure that all constraints are met, then these constraints will help us better manage the database table structure and avoid problems.
So, why use database schema language to describe the database table structure? First of all, the database schema language provides a unified standard to describe various entities and their relationships in the database, such as tables, fields, indexes, primary keys, foreign keys, stored procedures, triggers, etc.; secondly, the database schema language supports different databases Data migration between systems so that database applications across database systems can be implemented. Third, the database schema language can provide a series of security measures at the database level, including access control, transaction processing, secure backup, recovery, logging, etc. Finally, database schema language can also improve database performance, reduce development difficulty and error rates, and improve productivity.
Therefore, in this article, we will introduce the database schema language in detail, discuss its basic concepts and terminology, and let readers understand its core algorithm principles and operation steps through some examples. Hope to be helpful to readers!