The keyword of primary key constraint in mysql is

In MySQL, the keyword of primary key constraints is PRIMARY KEY

Detailed explanation:

In MySQL, primary key constraints are used for Identifies a unique and non-repeatable record in the table. Primary key constraints can be specified in the following ways:

• Explicitly specify the PRIMARY KEY keyword when creating the table
• Explicitly specify the PRIMARY KEY keyword when creating the column

Example:

<code class="sql">CREATE TABLE 表名 (
  字段名 数据类型 PRIMARY KEY
);</code>

Example:

<code class="sql">CREATE TABLE customers (
  customer_id INT NOT NULL PRIMARY KEY,
  name VARCHAR(255) NOT NULL
);</code>

In this case, the customer_id column is defined as primary key. This means that the customer_id value must be unique for each record in the table, and no duplicates are allowed.

Advantages of primary key constraints:

• Ensures uniqueness of records in the table
• Improves query performance because it allows MySQL to use indexes quickly Finding records
• Simplifies data maintenance because it prevents inserting or updating records with duplicate primary key values

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