V4RB2 vLink

[Ruslan Zasukhin]

On 11/22/04 10:32 PM, "erne" <ernestogiannotta at tiscalinet.it> wrote:

> hello Ruslan,
> 
> looking into new vLink class and have some questions
> 
> we create BinaryLink with DB method:
> DB.CreateBinaryLink(
>      inName as String,
>      inLeftTable as VTable,
>      inRightTable as VTable,
>     [inLeftPower as Integer = 1],
>     [inRightPower as Integer = 0],        // 1 : M
>     [inOnDelete as integer = 1],
>     [inStorageType as integer = 0],        // kDefault
>     inTemporary as Boolean = false) As VLink
> 
> how can we delete this if we don't need it anymore?
> 
> so the vLink object knows the Tables it is linking
> 
> but when we want to find linked we must call:
> vLink.FindLinked( inRecID as Integer, inTableA as VTable, inTableB as
> VTable ) as VSet
> 
> why must we specify the tables here?

> mmm... I see, we need specify the direction of desired link

Absolutely correct!

    inRecID this is RecID of tableA

> so it could also be implemented by index as in:
> vLink.FindLinked( inRecID as Integer, inTableA as Integer, inTableB as
> Integer ) as VSet

But what sense, Erne?
I think pointers on objects is the best choice.


> after all we are required to know the Index order of linked tables if
> we must link records by:
> vLink.LinkRecords( inRecIDs() as Integer )

Agree. Index of table is strict thing.
It correspond to the order of creation.

> anyway, to specify the 2nd table seems redundant as we have:
> vLink.DeleteLinkedRecords( inRecID as Integer, inTableA as VTable )
> vLink.DeleteAllLinkedRecords( inTableA as VTable )
> 
> so it should be enough:
> vLink.FindLinked( inRecID as Integer, inTableA as [VTable or Integer] )
> as VSet

I see your point...and

> unless vLink will be able to link more than 2 tables in the future

Exactly! Bingo! :-)

> in which case the LinkRecords, DeleteLinkedRecords and
> DeleteAllLinkedRecords methods must be updated

NO. because when link will have 3 branches, I still can say

    vLink.DeleteAllLinkedRecords( inTableA as VTable )

And this means break links to ALL linked tables of TableA.





-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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