Invalid executions

[stuartmcalpine]

If a dataset fails during copying the data, it has a left over database entry, but it remains "invalid".

However if the execution for that dataset is the default fabricated one, it gets created first, so there will be a left over execution. Should executions then also have a valid/invalid status?

[JoanneBogart]

I think that's the best option.
This is one case where I would consider deleting the execution entry, but that doesn't help - one still has the dataset entry which needs to refer to some execution.
So yes, let's add a status field for executions.