Help Views

[Former Member]

Why there is a restriction on secondary table to have an N:1 relationship , when help views implement outer joins ?

Can somebody explain this ?

Thanks in advance.

Regards,

Sinu.

Edited by: Sinu Mathew on Jul 8, 2008 11:34 AM

[Former Member]

Hi,

This Because of the Cardinality Issues.

Pls Follow the Link-

http://help.sap.com/saphelp_nw70/helpdata/en/b2/fbb859c64611d295dd00a0c929b3c3/content.htm

http://help.sap.com/saphelp_nw70/helpdata/en/cf/21ecd2446011d189700000e8322d00/content.htm

Regards,

Sujit

[Former Member]

hiii..

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.

There are some restrictions for selecting the secondary tables of a maintenance view or help view. The secondary tables have to be in an N:1 dependency to the primary table or directly preceding secondary table. This ensures that there is at most one dependent record in each of the secondary tables for a data record in the primary table.

N:1 dependency exists if the secondary table is the check table in the foreign key used.

If the secondary table is the foreign key table, the foreign key fields must be Key fields of a table or the foreign key must have the cardinality N:1 or N:C.

this will give you the detailed knowledge about your query......

reward if i could help you..

thanks...

[Former Member]

Thank u very much Mainak Sen.

But Outer join itself specifies that if there is no corresponding entry for a primary key in the secondary table then also the record is to be retrieved...but with the cardinality specification N:1 we are restricting the same....Please let me know this clearly.

Regards,

Sinu.

[Former Member]

Hi

Go through the link given below :

http://help.sap.com/saphelp_webas620/helpdata/en/cf/21ecd2446011d189700000e8322d00/frameset.htm

hope it will help you.

Rewards Points if useful.

Thanks & Regards

Nikunj Shah

[Former Member]

Hi,

You are right with your definition. but at the same time we must keep in mind that we are dealing with data of a database table. So here data consistency shoud be counted with preference over the general character of outer join or primary key.

since , every data is qniuely indentified by its primary key value only , we can't accept the data with NULL value in the primary key fields. So It can be said, this N:1 condition is putting this extra limitation is achieve the consistent data in help view.

Reward if found helpful.

Anirban Bhattacharjee

[Former Member]

Help Views:

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.

Regards

Abhijeet Kulshreshtha

Edited by: Abhijeet Kulshreshtha on Jul 8, 2008 1:18 PM