Failed to create list item for external list using REST API POST

Question

I've AN OData API, which I'm consuming in SharePoint via BCS and External List.

I already have the Get and Update functionality working using REST API to external list.

But when I try to add an item in the list, I'm getting the following error:

In the ULS Log the detail of the Internal Server Error(500), was

Internal Server Error. ---> Microsoft.BusinessData.Runtime.CannotConnectException

Here is the error using Fiddler:

message=Failed to create a list item for this external list based on the Entity (External Content Type) 'xxx-table-name-xxx' in EntityNamespace 'XXX'. Details: The remote server returned an error: (500) Internal Server Error.

stacktrace= at Microsoft.SharePoint.SPListDataSource.InsertItem(SPListItem itemToInsert, IDictionary dictValues) at Microsoft.SharePoint.SPListItem.AddOrUpdateItem(Boolean bAdd, Boolean bSystem, Boolean bPreserveItemVersion, Boolean bNoVersion, Boolean bMigration, Boolean bPublish, Boolean bCheckOut, Boolean bCheckin, Guid newGuidOnAdd, Int32& ulID, Object& objAttachmentNames, Object& objAttachmentContents, Boolean suppressAfterEvents, String filename, Boolean bPreserveItemUIVersion) at Microsoft.SharePoint.SPListItem.UpdateInternal(Boolean bSystem, Boolean bPreserveItemVersion, Guid newGuidOnAdd, Boolean bMigration, Boolean bPublish, Boolean bNoVersion, Boolean bCheckOut, Boolean bCheckin, Boolean suppressAfterEvents, String filename, Boolean bPreserveItemUIVersion) at Microsoft.SharePoint.SPListItem.Update() at Microsoft.SharePoint.SPListItemEntityCollection.Create() at Microsoft.SharePoint.ServerStub.SPListItemEntityCollectionServerStub.InvokeMethod(Object target, String methodName, ClientValueCollection xmlargs, ProxyContext proxyContext, Boolean& isVoid) at Microsoft.SharePoint.Client.ServerStub.InvokeMethodWithMonitoredScope(Object target, String methodName, ClientValueCollection args, ProxyContext proxyContext, Boolean& isVoid) at Microsoft.SharePoint.Client.Rest.RestRequestProcessor.InvokeMethodWithRequestODataEntry(Object target, ServerStub serverStub, MethodInformation methodInfo, RequestODataObject entry) at Microsoft.SharePoint.Client.Rest.RestRequestProcessor.InvokeMethodWithRequestODataEntry(Object target, ServerStub serverStub, String methodName) at Microsoft.SharePoint.Client.Rest.RestRequestProcessor.TryAddEntity(Object entity, ServerStub serverStub, Object& newEntity) at Microsoft.SharePoint.Client.Rest.RestRequestProcessor.Process() at Microsoft.SharePoint.Client.Rest.RestRequestProcessor.ProcessRequest() at Microsoft.SharePoint.Client.Rest.RestService.ProcessQuery(Stream inputStream, IList`1 pendingDisposableContainer)

Answer 1

I have a code which may be useful for you.
Try this-

    function CreateListItemWithDetails(listName, webUrl, newItemTitle) {

var itemType = GetItemTypeForListName(listName);
var item = {
    "__metadata": { "type": itemType },
    "Title": newItemTitle
}

$.ajax({
    url: _spPageContextInfo.siteAbsoluteUrl + "/_api/web/lists/getbytitle('" + listName + "')/items",
    type: "POST",
    contentType: "application/json;odata=verbose",
    data: JSON.stringify(item),
    headers: {
        "Accept": "application/json;odata=verbose",
        "X-RequestDigest": $("#__REQUESTDIGEST").val()
    },
    success: function(data) {  
        alert("New Item has been created successfully. ")
         },  
    error: function(data)  {   
        alert("Ooops, an error occured. Please try again.")
       }  
    });

};

function GetItemTypeForListName(name) {
return "SP.Data." + name.charAt(0).toUpperCase() + name.split(" ").join("").slice(1) + "ListItem";

}