Odata Services with Complex Types

[former_member220853]

Dear All

We have a requirement to create an OData Services with complex type . Structure of this type is as follows

Zparent (Structure name)

| name- String

|--------|  Table of ZChild (Structure name)

         |-------- name- string

         |---------value- String

Has anyone tried it and if yes what are the basic fundamental steps to accomplish it

I am a newbie therefore need some guidance

Points will be rewarded

Thanks in advance

Gaurav

[former_member184867 · Accepted solution]

Hi Gaurav,

   Complex Type is not the right technique to represent a parent child relationship of cardinality 1:N. A complex type inside an Entity works a group of individual properties. This is useful when you want to reuse same group in many Entities(or in Action). For example, consider a service with entity Customer and Invoice. Entity Customer has properties a) HomeAddress b)OfficeAddress  , entity Invoice has property ShippingAdress. So technically all three properties are of complex type Address . Moreover complex type is nothing but a structure, so it can not hold multiple values. 

  Now to address your requirement, you have to create Parent and Child entities separately. Then you have to create association between them where you can put your desired cardinality(here may be 1:N). Next you have to create a navigation property for the parent using this association. Hope this is helpful.

regards,

Atanu

[former_member220853 · Accepted solution]

Thanks for the reply

I have few more questions , even though I am able to define the association and create a cardinality of 1 for parent and 1..n for child .

Do I necessarily need to create Entity Sets as well?

If yes , then how do I use the association defined earlier

Do we need to define any referential integrity constraints etc  as well?

[jibin_joy · Accepted solution]

Hi Gaurav ,

These are the step for simple service ....

1. Create Two Entity ( Parent and Child ).

2. Create EntitySet (ParentCollection and ChildCollection) For about Entities

3. Create Association ParentAssnChild For Entity Parent and Child (based on ur scenario it will      1..n as u a mentioned above)

4. Create Association set ParentAssnSetChild for association  ParentAssnChild with entityset      ParentCollection and ChildCollection.

5. Goto Entity Parent create an navigation properties Provide Link name : ChildLink and      Association  ParentAssnChild which is created above

Regards,

Jibin Joy

[former_member220853 · Accepted solution]

Thanks a lot Jibin

So if understood correctly we can have atomic structures and defined their relationship or cardinallity by associations in Odata service .However if we have hierarchical structures then  it may not work very well because get_entity_set method generally will return data only on one structure so even if we have hierarchical structure we cannot copy it to et_entity_set because entity set expects an atomic structure and not a hierarchical structure

Thanks in advance

Gaurav

[jibin_joy · Accepted solution]

Hi Gaurav,

   this can be  overcome by $expand parameter ....

Reference ...

1. http://www.odata.org/documentation/odata-v2-documentation/uri-conventions/#46_Expand_System_Query_Op...

2. http://scn.sap.com/thread/3238025

Regards,

Jibin Joy

[Former Member · Accepted solution]

Hello,

Am i right that with this approache i will able to have access to ChildSet during design time in DPC ?

I've create Parent which have ChildSet 1:n

I was wondering that at runtime i will have struct like this

ParentVal1

ParentVal2

     ChildSet (like table)

Please answer or refer me to corect sources/tutorial

BR

Lucas

[jibin_joy]

Hi Gaurav ,

There are two ways to making an complex Entity

1. Direct Way -  Adding Complex Type in the Entity

      Problem with this way is that it is a 1:1 relationship . Its behavior like "append" and "include" in DDIC But based on scenario,  nested structure (ZChild) is a  table  so this technique is not possible .

2. In-direct Way -  Making relationship between two entity using association

       Based on my experience ur requirement can be done by creating two entity zparent as well as        zchild .  Cardinality can be handled  in the association corresponding to this entity.

Regards,

Jibin Joy