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Virtual business objects

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What is a virtual BO?

A virtual business object is not based on a table but on a database view. A view is therefore a prerequisite (see database objects).

Requirements for the view

The view must contain at least these columns (exact names!):

intid,         	-- Datensatzidentifizierer
strcreated,    	-- Ersteller als String
datcreated,		-- Erstellungsdatum
strchanged,		-- Änderer als String
datchanged,		-- Änderungsdatum
intversion		-- Datensatzversion

• intid must be unique when referenced.
• Reference columns start with intid_str….
• Nuclos determines data types automatically; for wrong types an explicit cast in the view helps (e.g. db_function(intid)::numeric(9,2)).

ID factory (PostgreSQL example)

To write via a virtual BO an ID factory (sequence function) is required:

CREATE OR REPLACE FUNCTION Y25N_IDFACTORY()
  RETURNS numeric
  LANGUAGE 'plpgsql'  COST 100
  VOLATILE 
AS $BODY$DECLARE
  id numeric;
BEGIN
   SELECT NEXTVAL('idfactory') INTO id;   RETURN id;
END;$BODY$;

Create a virtual BO

Create a new BO in the business object wizard and in step 2 via Show advanced properties:

• Virtual business object: select the prepared view (if missing it may be invalid).
• Id factory for VE (optional): DB function if writing through the BO – the BO then becomes editable automatically.
• Table name: leave empty for virtual BOs.

Advanced properties of the virtual BO.

Change a virtual BO

First adjust and save the view under database objects, then run the business object wizard again.

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