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This article shows you what is the only index keyword in mysql, the code is concise and easy to understand, it can definitely brighten your eyes. I hope you can get something through the detailed introduction of this article.

The keyword for the only index in mysql is unique index. Creating a unique index avoids duplication of data. There can be more than one unique index, but the value of the index column must be unique, and the value of the index column allows null values. To create a unique index, you can use the keyword UNIQUE to create with the table.

The keyword for the only index in mysql is unique index.

Related introduction:

Creating a unique index avoids duplication of data. There can be more than one unique index, but the value of the index column must be unique, and the value of the index column allows null values. If you can be sure that a data column will only contain values that differ from each other, you should use the keyword UNIQUE to define it as a unique index when creating an index on that data column.

For example:

To create a unique cable, you can use the keyword UNIQUE to create it with the table

Code implementation:

The above code creates a unique index named catename for the 'catid' field of the wb_ blog table.

If you do not need a unique index, you can delete:

Code implementation:

Mysql > ALTER TABLE wb_blog DROP INDEX catename; Query OK, 0 rows affected (0.85 sec) what are the keywords of the only index in mysql? have you learned any knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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