New functionality : [ReturnOnUpdate] attribute

ServiceStack.OrmLite
1

Hello,

For fields like RowVersion or some computed columns the value can change after an Db.Update(), so can we have an attribute like [ReturnOnInsert] but for update statements ?

Thank you

2

Can you provide an example of your optimal usage example and how you want it to work please.

3 
// servicemodel
public class MyEntity : IHasId<int>, IReturn<MyEntity>
{
    [AutoIncrement]
    [ReturnOnInsert]
    public int Id { get; set; }

    public string Name { get; set; } = null!;

    [ReturnOnInsert]
    [ReturnOnUpdate]
    public ulong RowVersion { get; set; }
}

// in my service
public async Task<MyEntity> PutAsync(MyEntity request)
{
    await Db.UpdateAsync(request);

    // now request.RowVersion contains the new RowVersion value generated by the database so we can return it directly to the client.

    // without this new [ReturnOnUpdate] attribute, we would need to re-query the database to get the new RowVersion value with something like this :
    // return await Db.SingleByIdAsync<MyEntity>(request.Id);

    return request;
}

// for SQLServer the query would look something like that :
update "MyEntity" set "Name"='newvalue'
output inserted."RowVersion"
where "Id"=1

I don’t know if it’s doable

4

The Update APIs return the number of rows affected, that’s why I’m looking for what the ideal proposed API should look like?

5

Not sure if I understand your question.

I don’t think the API should change, just like when you have implemented the [ReturnOnInsert] attribute for the Insert and InsertAsync API

If the [ReturnOnUpdate] is present on some properties, those properties should be refreshed after the update for Update and UpdateAsync API when it updates only 1 POCO

It would be nice if it also worked when you want to update an array of POCO

And maybe you could do that for UpdateOnlyFields and UpdateOnlyFieldsAsync too

6

Doesn’t look like it’s going to be possible with existing APIs, with a number of issues preventing it:

  • The return type of Update APIs are int to return the rows updated
  • The built-in Optimistic Concurrency support requires returning the number of rows updated to ensure the row version hasn’t been changed.
  • Most of the Update APIs accept an array of objects to update params T[] objs
7

Ok I had a doubt and I’ve just tested Insert and InsertAll with an array of POCO.
Each POCO containing some [ReturnOnInsert] properties and it doen’t work as I excepted : those ReturnOnInsert properties are not updated in the array after the insert.
Is this a bug ?

8

Can you show an example of how you’re using it, also the RDBMS you’re using.

Also where did you learn about the feature?

9

I’m using it for SQL Server.
I’ve learn about it here : SQL Server Features
Also mentioned here : Declarative Dev Model using Attributes

My typical use case is pretty simple :

public class MyEntity : IHasId<int>, IReturn<MyEntity>
{
    [AutoIncrement]
    [ReturnOnInsert]
    public int Id { get; set; }

    public string Name { get; set; } = null!;

    [ReturnOnInsert]
    public ulong RowVersion { get; set; }
}
public class InsertMyEntity : IReturn<MyEntity[]>
{
    public MyEntity[] Items { get; set; } = null!;
}

// in my service
public async Task<MyEntity> PostAsync(MyEntity request)
{
    await Db.InsertAsync(request);
    // working example : here request.Id and request.RowVersion contains the value generated by the database 

    // here i'm also logging inserted POCO in an audit trail
    return request;
}
public async Task<MyEntity[]> PostAsync(InsertMyEntity request)
{
    await Db.InsertAllAsync(request.Items);
    // not working as expected : here none of the POCO in request.Items have their Id and RowVersion updated with the value generated by the database 

    // here i'm also logging inserted POCOs in an audit trail
    return request.Items;
}