Creating relations in mySQL, how do u do this? More Details needed please!

[bulgaria_mitko]

I have created a database with 2 tables one with Products->ProductID and Products->TypeID and the other with ProductsType->TypeID and i want to related them so when i delete a ProductType it will NOT delete all the Products related to that ProductType. How have to set the ON DELETE and ON UPDATE in order to do this and also how to u set them when u delete a ProductType to delete all the Products related to that ProductType? Thank you very much!  ???

[btherl]

The default is NOT to delete related data.

If you are finding that related data is deleted automatically, then it is due to something you have added to the table definitions.  It could be related to foreign keys.  There is no requirement to specify foreign keys.

[bulgaria_mitko]

oh yeah and the most important question what is foreign key? i know already what is primery key, but foreign key?  ???

[artacus]

A foriegn key is the primary key of a related table.
So if you have a products table:
product_id <- primary key
category_id <- foreign key in this table/ primary key of the categories table

[minderella]

There are several rules you have to abide by if you plan on using foreign keys.  From what I know, InnoDB is the only engine that can implement foreign keys.  I strongly suggest that you read the MySQL manual regarding the construction of InnoDB databases.