Shulou(Shulou.com)05/31 Report--

This article is to share with you about how to create field constraints in the Oracle database, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

Non-empty constraint

Unique constraint

Constraints on the value of a field

Default value

Foreign key constraint

Create table tab_class (class_id number primary key, class_name varchar2 (10) not null unique) Create table tab_stu (stu_id number,-- student name, cannot be empty, cannot repeat stu_name varchar2 (20) not null unique,-- student name can only be male or female stu_gender varchar2 (6) not null check (stu_gender='male' or stu_gender='female'),-- student age can only be between 18 and 60 stu_age number check (stu_age > 18 and stu_age 18 and che_age)

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