Help Views

source:http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21ecd2446011d189700000e8322d00/content.htm

  You have to create a help view if a view with outer join is needed as selection method of a search help.

  The selection method of a search help is either a table or a view. If you have to select data from several tables for the search help, you should generally use a database view as selection method. However, a database view always implements an inner join. If you need a view with outer join for the data selection, you have to use a help view as selection method.

  All the tables included in a help view must be linked with foreign keys. Only foreign keys that have certain attributes can be used here. The first table to be inserted in the help view is called the primary table of the help view. The tables added to this primary table with foreign keys are called secondary tables.