Graphical Table Join Definition 

If several tables are all linked within a SELECT statement, this is known as a join. The result set is a table, each of the lines of which contains all the fields of all the tables used in the join. The links between the various tables used in the join are all specified separately. These specify the exact combinations of records from the individual tables that become part of the result set.

The result of a table join is also a (flat) table! Therefore hierarchical relationships between tables cannot be analyzed using a table join. This requires logical databases.

For more detailed information about table joins you should refer to the online documentation for the ABAP SELECT statement.

You can also define table joins in a graphic design mode if certain technical software requirements have been fulfilled. The system then simulates the join including the relationships between its individual tables.

Table joins must already be defined before you maintain InfoSets and QuickViews. With InfoSets, you can switch off graphical join definition under Settings ® Settings... and create joins using the procedures described in Classical Table Join Definition instead.

If certain technical software requirements are fulfilled, graphical join definition always appears as the standard setting.

The following functions are available on the Join Definition screen (Note: Those functions available in pushbutton form are written in italics):

Insert table

Enter the name of the table you want to insert in the dialog box. The table is then displayed in a window, that is the table fields and their long texts are displayed. Key fields are marked with a relevant icon. The dialog box can be moved if you so wish.

Propose join conditions

The system inserts standard proposals for joining two tables. The defaults suggested are derived based on the foreign key dependencies stored in the Dictionary or on the key fields of the tables used in the join.

Create links

The join conditions for your tables are displayed in line form. In order to create such a line, click on a starting field. Then, leaving your left mouse button depressed, drag your cursor to the field that you want to link to. If linking of the two fields is allowed, the system creates a line after you have released the left mouse button.

Define link type

Place the cursor on the line and depress the right mouse button. A context menu appears where you can choose to display or delete join conditions. If you choose to display the join conditions, a dialog box appears where you can set the join type to either inner join or left outer join. You can find further information Classical Table Join Definition.

Delete table

A dialog box appears where you can enter the name of the table you want to delete. Alternatively, you can select the corresponding pushbutton in the table window (Closebox).

Alias table

Choose Alias table if you want to include the same table in a join twice. Define an alias name for the appropriate table as described in Assigning Additional Tables. You can include the table in your join under both its original name and its alias.

Check

The system checks to see if the links between tables make sense, or if tables have been inserted, but not joined.

Reference field

Placing your cursor on a quantity or currency field and choosing Reference field causes the system to display the reference table containing that field's corresponding unit of measure or currency.

Field documentation

Place your cursor on a field for which you wish to display documentation. Information about the field's technical definition is displayed. Two fields can be linked only if both fields have the same data type in the Dictionary (including the length attribute). This means that two fields can be linked if they have the same domain.

You can find out about further restrictions and rules on how to use joins in the section on Classical Table Join Definition.

When you are done defining a table join for a QuickView, choose Back from the Join Definition screen to continue maintaining QuickViews. Your join definition is then saved together with your QuickView.

If you are using the graphical join definition while maintaining an InfoSet, choose Back to return to InfoSet maintenance and save manually.