Relationships between two tables ? (Primary key)

PHPLOVER07

Hi,

How i can make relationships between two tables with primray key, key ?

Thanks

maxpup979

are you referring to using foreign keys to point to a primary key?

tomhath

Add a foreign key constraint to the child table.

http://dev.mysql.com/doc/refman/5.0/en/innodb-foreign-key-constraints.html

PHPLOVER07

Thanks

maxpup979

I'm referring to use PRIMARY KEY and KEY only ?

Roger_Ramjet

tomhath wrote:
Add a foreign key constraint to the child table.

http://dev.mysql.com/doc/refman/5.0/en/innodb-foreign-key-constraints.html

Only for InnoDB tables, which may not be the engine of choice.

Everyone has their own preferred naming conventions, or none if they are fools. My own choice is
a) NEVER name a column just 'id' - name the primary key for the table : table1_id
b) when it is used as a FK in another table name it the same - to me it makes the relationship obvious.

Now there are many more complex naming conventions around; eg if you use the table generating tools in ms access it will add PK:FK suffixes to the chosen name when you specify the key constraint. Fine if you are going to drag and drop in a query generator, but a real pain when you are hand coding sql.