Planning parent child relationship in VLF WIN

Planning parent-child relationship in VLF-WIN

For VLF-ONE programs see In VLF-ONE Adding Children is Simpler

In VLF-WIN setting up the key structures for parent-child relationships can be simplified by filling in a table like this.

Here a SECTION may contain EMPLOYEEs.

An EMPLOYEE may have associated SKILLs.

An EMPLOYEE may have associated DOCUMENTs.

BO	ROLE	AKey1	NKey1	AKey2	NKey2	AKey3	NKey3	AKey4	NKey4	AKey5	NKey5
SECTION	PARENT	#DEPTMENT	Implicitly used by parent	#SECTION	Free for children to use	Free for children to use	Free for children to use	Free for children to use	Free for children to use	Free for children to use	Free for children to use
EMPLOYEE	CHILD (of SECTION)	Must be same as parent's #DEPARTMENT value	Implicitly used by parent - so must have same default value.	Must be same as parent's #SECTION value	Implicitly used this by child	#EMPNO – should make this child unique within this DEPARTMENT and SECTION	Free for children to use	Free for children to use	Free for children to use	Free for children to use	Free for children to use
SKILL	CHILD (of EMPLOYEE) GRANDCHILD (of SECTION)	Must be same as parent and grandparent's #DEPARTMENT value	Implicitly used by parent and grandparent - so must have same default value.	Must be same as parent and grandparent's #SECTION value	Implicitly used by parent - so must have same default value.	Must be same as parent's #EMPNO value	Implicitly used by this child	#SKILLCODE – should make this employee's skill unique within this DEPARTMENT and SECTION and EMPLOYEE	Free for children to use	Free for children to use	Free for children to use
DOCUMENT	CHILD (of EMPLOYEE) GRANDCHILD (of SECTION)	Must be same as parent and grandparent's #DEPARTMENT value	Implicitly used by parent and grandparent - so must have same default value.	Must be same as parent and grandparent's #SECTION value	Implicitly used by parent - so must have same default value.	Must be same as parent's #EMPNO value	#DOCNUMBER – should make this employee's document unique within this DEPARTMENT and SECTION and EMPLOYEE	Free for children to use	Free for children to use	Free for children to use	Free for children to use

The parent-child association rules that you must follow are:

Any child business object must have exactly the same keys as its parent plus one or more keys to uniquely identify itself.

A child business objects can use the free keys not used by its parent. They can only start immediately after the last parent key used (real or implicit) working from left to right in the key structure.

You might also consider condensing key structures when your theoretical planning is finished – the keys are programmatic and not visible to end-users.

For example: by choosing #DEPTMENT + “-“ + #SECTION as the AKey1 value in the table above you could condense it towards the left by two columns - freeing up a considerable amount of key space.