1. A method of porting program code having at least two types of configuration repositories describing a single configuration of the program code, the method comprising: detecting a foreign key in a first configuration item in a first repository, the foreign key pointing to a second configuration item in a second repository, the first and second repositories being of different repository types; creating a logical reference using the foreign key, the logical reference being associated with the first configuration item and referencing an indeterminate configuration item of the same data type as the second configuration item; copying a portion of the first repository to an exportable format; and storing the logical reference with the exportable format to enable resolving the foreign key in the first configuration item to a third configuration item in a third repository, the second and third repositories being of the same repository type.