CODEWITHSUNDEEP
c#asp.net-coreazure-cosmosdb
Alex Gordon
Alex Gordon

Reputation: 60811

how to add a node if it doesn't exist'

I'm attempting to run some patch operations:

ItemResponse<dynamic> response = await _container.PatchItemAsync<dynamic>(
    id: loanParent.LoanNumber,
    partitionKey: new PartitionKey(loanParent.LoanNumber),
    patchOperations: new[] {
        PatchOperation.Replace("/loandetails/loanname", loanParent.Loan.LoanDetails.LoanName),
        PatchOperation.Replace("/loandetails/loandescription", loanParent.Loan.LoanDetails.LoanDescription)
    }
);

However, I'm getting this exception because those nodes do not exist yet. Here's the full document:

{
    "loannumber": "abc123",
    "id": "abc123",
    "participants": [
        {
            "firstname": "alex",
            "lastname": "gordon"
        },
        {
            "firstname": "liza",
            "lastname": "gordon"
        }
    ],
    "_rid": "1sAyAggggggA==",
    "_self": "dbs/1sAyAA=gggggAAAAAAAA==/",
    "_etag": "\"d900c069-0000-4440-0000-63642d840000\"",
    "_attachments": "attachments/",
    "_ts": 1ddd636
}

Microsoft.Azure.Cosmos.CosmosException : Response status code does not indicate success: BadRequest (400); Substatus: 0; ActivityId: a6ab67d6-f73e-4b3c-b03e-1d9b6cc54dba; Reason: (Message: {"Errors":["For Operation(1): Given Operation can only create a child object of an existing node(array or object) and cannot create path recursively, no path found beyond: 'loandetails'. Learn more: https://aka.ms/cosmosdbpatchdocs"]}

How do we create the node structure if it does not exist?

Upvotes: 2

Views: 694

Answers (2)

Tanuki
Tanuki

Reputation: 849

For anyone else coming here after realising that PatchOperation.Replace throws an error if field doesn't exist and wanting to add or replace a field instead (aka do an upsert).

The good new is that their upsert equivalent is an Add operation (aka PatchOperation.Add) which will properly add or replace field value like any good little upsert should do.

Here is some git discussion mentioning it, unlike their rather unhelpful documentation: https://github.com/AzureCosmosDB/PatchPrivatePreviewFeedbackGroup/issues/2

Upvotes: 0

Sajeetharan
Sajeetharan

Reputation: 222682

Patch works on an existing document, you need to make sure the object exists before you perform any operations such as add,remove,replace,set and increment.

In this case first you can use Add operator to create the loandetails and then the subsequent operations can be performed

Upvotes: 1

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