When a table is linked to a target, it implies that the user has previously made sure to have an index available allowing the linking to be carried out.
If this index is a single component, the system automatically takes the checking of the "Index" and "Key components" fields. In fact, it has available in this case all the information necessary.
On the other hand, if the index is multi-component, the user is invited to specify the index to be used to carry out the join. The latter case is aided by the use of a selection list containing all the available indexes in the table to be linked.
This field does not have an object within the framework of a grouping support. As a consequence, it is deactivated.