This blog will explain how to implement multi-level create deep.
Prerequisite, please make sure you are familiar with create deep implementation via Gateway:
Step by Step development for CREATE_DEEP_ENTITY operation
For multi-level create deep, we assume this following scenario:
Here, FirstSon & SecondSon are the first-level deep of father, FirstGrandSon is the first-level of FirstSon but second-level of Father.
Then How to implement this create-deep scenario?
1. Create entities/associations in SEGW which map to this relationship.
Four entities are created: Father/FirstSon/SecondSon/FirstGrandson; Each entity has three properties: Key/Property1/Property2
Three associations are created: "Father to FirstSon" & "Father to SecondSon" & "FirstSon to FirstGrandSon"
2. Generate and register the ODate Service.
I assume you are familiar with these general Gateway steps 
.
3. Implement create_deep_entity method.
First create the multi-level deep structure which can holds the nested data from input; Then use io_data_provider to get the input.
Here I just write simple code snippet, as long as we can get nested data in the runtime.
4. Test in RestClient
I used to try to test the multi-level create deep in our traditional GW client and using XML format as payload. Nested data can be transferred into our create_deep_entity method, but the position of the nested data in second level is wrong. Thus, I strongly suggested to use JSON format as payload. Since our GW Client doesn't have a good support json fromat. I recommend to use the RestClient. (In RestClient you have to first get CSRF token and then post)
Payload:
{
"Key": "Father-Key",
"Property1": "Father-Property-1",
"Property2": "Father-Property-2",
"FirstSon": [
{
"Key": "FirstSon-Key-1",
"Property1": "Firstson-Property-1",
"Property2": "Firstson-Property-2",
"FirstGrandson": [
{
"Key": "GrandSon-Key-1",
"Property1": "GrandSon-Property-1",
"Property2": "GrandSon-Property-2"
}
]
},
{
"Key": "FirstSon-Key-2",
"Property1": "Firstson-Property-3",
"Property2": "Firstson-Property-4",
"FirstGrandson": [
{
"Key": "GrandSon-Key-2",
"Property1": "GrandSon-Property-3",
"Property2": "GrandSon-Property-4"
},
{
"Key": "GrandSon-Key-3",
"Property1": "GrandSon-Property-5",
"Property2": "GrandSon-Property-6"
}
]
}
],
"SecondSon": [
{
"Key": "SecondSon-Key-1",
"Property1": "SecondSon-Property-1",
"Property2": "SecondSon-Property-2"
},
{
"Key": "SecondSon-Key-2",
"Property1": "SecondSon-Property-3",
"Property2": "SecondSon-Property-4"
},
{
"Key": "SecondSon-Key-3",
"Property1": "SecondSon-Property-5",
"Property2": "SecondSon-Property-6"
}
]
}
5. Check if the multi-level nested data is mapping to the right position in our runtime.
Father-level data:
Son-level data (deep to father):
Grandson-level data (deep to FirstSon):
FirstSon[1] has one entry; FristSon[2] has two entry; as payload expected.
Now we get the multi-level nested data in the right position, then we can do anything we want in following .
Hope it helps!