# Simple summary Keys are in Dynamics AX

There is a maximum of one Primary Key per table, whereas a table can have several alternate keys. The primary key is usually the type of key that other tables, called child tables, refer to when a ...

• There is a maximum of one Primary Key per table, whereas a table can have several alternate keys. The primary key is usually the type of key that other tables, called child tables, refer to when a foreign key field in those other tables need a relational identifier.

• For new tables the default is a primary key based on the RecId field , incremented number or a completely meaningless number that is generated by the system surrogate key.

• Alternate key can be chosen as the Replacement Key of a table that can display on forms instead of a meaningless numeric primary key value. Each table can have a maximum of one replacement key.

• Natural key has meaning to people. Most replacement keys are natural keys.

• Relations represents a foreign key.