Renaming models in database with existing data when using RavenDb - ravendb

Question

Is there any 'easy' way to rename models in RavenDb when the database already has existing data? I have various models which were originally created in another language, and now I would like to rename them to English as the codebase is becoming quite unmaintainable. If I just rename them, then the data won't be loaded because the properties don't match anymore.
I would like the system to automatically do it on first load. Is there any best way how to approach this? My solution would be:
Check if a document exists to determine if the upgrade has been done or not
If upgrade has not been done, execute patch scripts to update fields
Update document to know that the upgrade has been done

Answer 1

I'd recommend you create new documents from the old documents.
This can be done pretty easily using patching via docStore.UpdateByIndex.
Suppose I had an old type name, Foo, and wanted to rename it to the new type name, Bar. And I wanted all the IDs to change from Foos/123 to Bars/123.
It would look something like this:
var patchScript = #"
// Copy all the properties from the old document
var newDoc = {};
for (var prop in this) {
if (prop !== '#metadata') {
newDoc[prop] = this[prop];
}
}
// Create the metadata.
var meta = {};
meta['Raven-Entity-Name'] = newCollection;
meta['Raven-Clr-Type'] = newType;
// Store the new document.
var newId = __document_id.replace(oldCollection, newCollection);
PutDocument(newId, newDoc, meta);
";
var oldCollection = "Foos";
var newCollection = "Bars";
var newType = "KarlCassar.Bar, KarlCassar"; // Where KarlCassar is your assembly name.
var query = new IndexQuery { Query = $"Tag:{oldCollection}" };
var options = new BulkOperationOptions { AllowStale = false };
var patch = new ScriptedPatchRequest
{
Script = patchScript,
Values = new Dictionary<string, object>
{
{ nameof(oldCollection), oldCollection },
{ nameof(newCollection), newCollection },
{ nameof(newType), newType }
}
};
var patchOperation = docStore.DatabaseCommands.UpdateByIndex("Raven/DocumentsByEntityName", query, patch, options);
patchOperation.WaitForCompletion();
Run that code once at startup, and then your app will be able to work with the new name entities. Your old entities are still around - those can be safely deleted via the Studio.