There are thousands of different transaction codes available in SAP, and each one serves a specific purpose. With the right knowledge and understanding, you can use transaction codes to carry out any task imaginable in SAP. The complete list of SAP TCodes
As you known about SAP OData. In this blog lets look at the basic structure of the OData service. It have mainly two parts
Service document
Service metadata document.
Service document
Service documents consists of all list of resources URI’s that can be accessible. ZSL_EPM_DEMO is the OData service which we will be going to build in future tutorials. Basically this service will retrieve sales order data.
Lets look at what information does this service documents holds.Service document is accessible through the URI.
Service metadata document
Service metadata documents contains meta data of all elements in the service. You can see the metadata of a service by simple adding “$metadata” to the service URI.
Different elements we see in SAP OData service are
Entity Type: Entity is like work area which holds empty or one record data. As we have different fields in work area here also we have different fields and we call them as Properties.Each Entity should have at least one key field.
Entity Set: Entity Set is a collection of same entity types. It is like internal table which holds n records of same type. For example list of sales orders is a Entity Set.
Property: Itrepresents a primitive data type element.It is like a single field in a work area or single column in a table. one or more properties are used to create an Entity Types.
Association: It defines the relation between different entity types.For example if we have two entity types one for Sales Order header and other for Sales Order Item we can build the association between these two entity types with cardinality.
Navigation property: Entity Types include one or more navigation properties.It is specific type which acts like a link to the other Entity types based on cardinality provided in the Association property. To create the navigation property for an entity type we need first define the association between those entity types.
SAP Netweaver Gateway provides REST based and open interface that implements simple access to SAP systems via OData protocol.
With SAP Netweaver Gateway any one can i.e. any user interface(UI) can access the data through OData protocol.
Is this the only one that can communicate to other systems in SAP portfolio? the answer in NO. We have SAP PI system to exchange information between different systems and especially between a company and 3rd parties.
But the main difference between SAP PI and SAP Netweaver Gateway is in their usage.
SAP Netweaver PI is to communicate the information between system-to-system, but SAP Netweaver Gateway is system-to-user.
Lets look at what is OData and REST mean actually.
What is OData?
OData is REST based protocol to access and update the data. OData is build on Atom Publishing Protocol(AtomPub), XML and JSON.
This make the protocol easy to understand and use.
In short OData is an Online Database Connectivity(ODBC) for the web. It offers a simple and uniform way of sharing the data on protocol level which in turn enables broad integration across different products and platforms.
For more information
What is REST?
The full form of REST is REpresentational State Transfer. REST is not a kind of protocol, it is a architectural style.It builds on HTTP.
An architecture is a REST based when it complied these constraints
Client Server architecture
Statelessness
Cache-ability
Layered system
Uniform Interface
Code on demand
Let put this simple, to access list of sales orders in SAP we can access through an URI(Unified Resource Identifier) and if we want to get the data of particular sales order data we just need to change the URI and add the sales order # to URI.
Congrats!! you have successfully learned about what is OData and REST and how it works Please stay tuned to us for more SAP Netweaver Gateway tutorials.
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