When I try and create references, the software always generates a new column as a foreign key. Is it possible to set existing columns as foreign key instead? When creating my tables primary keys are already set into child tables which would be the foreign keys. When I draw the reference line across it still just adds another column that I don't require. For junction tables I am setting the primary as a compound key but those columns are also the foreign keys from the 2 parent tables. On my course we have to add foreign key constraints as a separate sql command. This is my first database so some confusion but I am trying to use a data modeller for clarity instead of working purley from the SQL command prompt in oracle. thanks Rob
When creating my tables primary keys are already set into child tables which would be the foreign keys. When I draw the reference line across it still just adds another column that I don't require.
For junction tables I am setting the primary as a compound key but those columns are also the foreign keys from the 2 parent tables. On my course we have to add foreign key constraints as a separate sql command. This is my first database so some confusion but I am trying to use a data modeller for clarity instead of working purley from the SQL command prompt in oracle.
thanks
Rob