Working on joins and relations

To view the join hierarchy for a mapping

  1. Open the Business Object Mappings list by right-clicking on the appropriate data source on the Data Sources tab.
  2. Locate the primary mapping for which you want to view the join hierarchy. Right-click on the mapping and select Joins from the contextual menu.

The Table Join Hierarchy window opens. It shows the joins defined (if any) for the mapping you selected.

The Table Join Hierarchy window provides a graphical display of how tables are joined for your selected mapping. It includes icons to indicate the following:

main table Indicates the main table to which all other joined tables are ultimately related as foreign tables. There is always one and only one main table for each mapping. It is the same table referenced as the primary table for the mapping. Next to this icon is the name of the primary table from the database. No additional Description is provided.
left outer join Indicates a left outer join operation. The resulting join includes all of the records from the first (left) of the two tables, even if there are no matching values for records in the second (right) table. Next to this icon is the name of the second (right) table of the join, followed by a space and the alias name for the join; the name of parent icon indicates the first (left) table. The Description indicates the full join statement, including all parent statements.
inner join Indicates an inner join operation. The resulting join includes only those records from the first (left) table that have at least one matching record in the second (right) table; records with no matches will not be included in the join. Next to this icon is the name of the second (right) table of the join, followed by a space and the alias name for the join; the name of parent icon indicates the first (left) table. The Description indicates the full join statement, including all parent statements.
relation Indicates the relation that applies to its parent join. This is drawn from the Table Relations list for your data source. The relation identifies the primary and foreign key fields for the left and right tables, respectively. Multiple relations can be used for tables using compound keys. No name is given for the relation. The Description indicates the relation statement.
joint extension Indicates a join extension. Each relation can have zero or one extension. Join extensions are defined using free-form SQL expressions, which are "ANDed" verbatim to the other default join criteria established by the join hierarchy. This is used to further restrict the rows included in the join result, typically based on user settings in the session context.
exists Indicates an exists predicate, which selects data based on the presence (or absence) of other values.

The Table Join Hierarchy window is arranged to indicate how the various join statements are related to each other. Complex arrangements can be established by nesting several joins inside of one another. Expansion boxes next to each join enable you to expand and contract the tree structure, just as with a standard Windows Explorer folder hierarchy display.