mysql - how many index per database table? -

How many indexes are preferred for a table in MySQL ??

I have a company table where I am mostly id , state , and category To search for.

There is no single answer for this question: Make many indexed queries sufficiently It is necessary to make enough, and not.

You have to close various things when deciding the index:

• The more indexes you have, the slower inserts and updates will be made (because they update all indexes Some columns do not need to be indexed (for example,
• A 'gender' column where only possible value "M" Or "F")

For its special scenario, it seems like three indexes, i On the one (if it is primary key, it is already an inherent index), on one state and one square, enough will be enough.