{Olingo4} Doubts in Odata V4

[Madhawa Kasun Gunasekara <ma...@gmail.com>]

Hi All,

I'm new to odata. I have some doubts in odata. hope you guys will help to
clear those doubts,
Please find those doubts below,

1, What is the use case of Container, EntitySets ?
As far what I understood is,
Container is used contain the data model. therefore we used to create more
than one containers when there are more than one data models in the service.

EntitySet is used to group the EntityTypes, for example there can be People
entity sets which contains two entityTypes, Students and Teachers


2. What to use case of Etag?
Etag is a unique number for each entity, It is not unique for EntityTypes.



Please let me know above description are correct or wrong.

Thanks
Madhawa

Re: {Olingo4} Doubts in Odata V4

["Bolz, Michael" <mi...@sap.com>]

Hi Madhawa,

> 1. What is the use case of Container, EntitySets ? 
> As far what I understood is, Container is used contain the data model. therefore we used to create more than one containers when there are more than one data models in the service.
> EntitySet is used to group the EntityTypes, for example there can be People entity sets which contains two entityTypes, Students and Teachers

In short EntityTypes defines the data model of an entity e.g. a People. A EntitySet defines a more specific group e.g. Student for which afterwards data is created (for more details see [1]).

> 2. What to use case of Etag?

An ETag (defined by HTTP protocol) is used for concurrency control and is therefore relevant for the data (e.g. an Entity) and not for the data model (EntityType).

I hope this clarifies and if not do not hesitate to ask more  ;o)

Best regards, 
Michael

[1]: http://docs.oasis-open.org/odata/odata/v4.0/errata02/os/complete/part1-protocol/odata-v4.0-errata02-os-part1-protocol-complete.html#_Toc406398200
[2]: https://en.wikipedia.org/wiki/HTTP_ETag

From:  Madhawa Kasun Gunasekara
Reply-To:  "user@olingo.apache.org"
Date:  Tuesday 7 July 2015 00:04
To:  "dev@olingo.apache.org", "user@olingo.apache.org"
Subject:  {Olingo4} Doubts in Odata V4

1, What is the use case of Container, EntitySets ? 
As far what I understood is,
Container is used contain the data model. therefore we used to create more than one containers when there are more than one data models in the service.

EntitySet is used to group the EntityTypes, for example there can be People entity sets which contains two entityTypes, Students and Teachers


2. What to use case of Etag?
Etag is a unique number for each entity, It is not unique for EntityTypes.