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This article is about how many indexes can be created in a table in mysql. The editor thought it was very practical, so I shared it with you as a reference. Let's follow the editor and have a look.

A table in mysql can have multiple unique indexes. If you can determine that a data column contains only 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.

A table in mysql can have multiple unique indexes.

If you can be sure that a data column will only contain values that differ from each other, you should define it as a unique index with the keyword UNIQUE when you create an index on that data column.

The benefits of this:

First, it simplifies the management of the index by MySQL, which makes the index more efficient.

Second, when a new record is inserted into the data table, MySQL will automatically check whether the value of this field of the new record has already appeared in this field of a record; if so, MySQL will refuse to insert the new record.

In other words, the unique index can guarantee the uniqueness of the data record. In fact, in many cases, the purpose of creating unique indexes is not to improve access speed, but to avoid data duplication.

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