How to create relationship between custom tables in CDM

[nikil]

Hello

I have created two custom tables in CDM, item and item category. I want to create a relationship between these tables. I added Item Category field in Item table and picked data type as a Picklist. However in the properties pane's Picklist drop down, I do not find the custom Item Category table I have created.

Please advice.

Regards 

[DaveB · Accepted solution]

Lookup's are history in CDS databases created in new environments. Now you manage relationships when designing an Entity.

The screen shot shows Item - ItemCategory.

If you work with a legacy CDM database in a migrated environment it still has Lookup's.

Dave

[nikil]

Thanks!

[IsaiahA]

Thank you very much for your response. I did create the relationship as indicated. However, I do not know how to manage the keys (primary & foreign key). Is there a step by step process to relate keys the keys? 

Thanks, 

Isaiah A.

[DaveB]

You drag-n-drop / delete fields to compose the entity key in the Keys tab...

[IsaiahA]

Sorry, it appears I am not making myself clear. Let me explain it further. Suppose I have an entity called "Title" with TitleID as my primary key. And I have another entity called Employee, which has is own primary key (EmployeeID), and a another column called TitleID. "Title" is the primary table and "Employee" is the secondary table. How do I relate Employee.TitleID with Title.TitleID in a one-to-many relationship? 

Thanks,

Isaiah. 

[DaveB]

I have only discovered how to create 1-to-many lookup relationships.

#1 Make field 'TitleID' of Title entity the key

#2 For Employee entity create a relationship to Title entity and call it 'EmployeeTitleID'.

In #2 it creates a new extra field to support the relationship, the original 'Employee.TitleID' field is not used. I cannot see any way to reuse this field in the new CDS databases.

[Vijeta]

Hello IsaiahA,

When you create a relation from a child entity to a parent entity you are creating a 1:n relationship. We automatically create a lookup field on child entity and relate it with the primary key of the parent entity.

Thanks