mysql - is this possible to made two primary key in one table -

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hi want know is possible make primarykey in 1 table in mysql. if yes please tell me concept behind this. because have seen table in 2 primary key there no auto increment set

you can have 1 primary key, but:

  • you can combine more 1 column primary key (maybe it's have seen)
  • the primary key don't needs auto-increment, has unique
  • you can add more 1 index 1 or more colums speed select-statements (but slow down insert / update)
  • those indexes can marked unique, wich means don't let insert second row same content in index-fields (just primary key)

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