Auto Join

Auto Join is a feature in JReport that will join tables together based upon certain selected criteria.  The following are the defaulted criteria in Auto Join.

• Primary Keys with Like Names: A primary key is a field or a combination of fields that uniquely and specifically identifies a record.   Your credit card number is an example of a primary key because it specifically links to your birthday, credit history, address, etc.  In this case primary keys with identical names from different tables are joined.
  
  
• Foreign Keys: This is a reference from Table A to a primary key in Table B.  For example, an order form in Table A shows information about purchases that are made by a customer.  It can also show this customer's ID #.  That customer ID # refers to a record in Table B which lists a specific address, phone number, name, etc for that customer.  The customer ID # in Table A is a foreign key because it links the customer's ordering information in Table A to the customer's information in Table B.
  
   
• Like Column Names: This is a link between two columns with the same name found in two different tables.