Q

Multi-column primary keys

I'm using MySQL, and I need to know how to create a primary key for a table that contains more than one attribute. For example, I would want both the last_name and first_name attributes to be a singular primary key.

MySQL supports multi-column primary keys just like other popular database management systems. If you haven't originally defined the table with a primary key, you can ALTER the table with syntax similar to the following:

alter table MyTable
  add primary key (Last_Name, First_Name);

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This was first published in April 2002

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