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This article mainly explains "what are the two types of mysql constraints". The content of the explanation is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn what are the two types of mysql constraints.

Description

1. Column-level constraints: create adds the fields after the fields when creating the table, and restricts the fields of the specified columns.

For example, the create table table name (name unique,age). What limits is the uniqueness of name.

2. Table-level constraints: when create creates a table, it is added before parentheses and after all fields.

Such as the create table table name (name,age,unique (name,age)). What is limited is the only thing that name+age unites, also known as federated constraints.

Example

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