Forcing a string field to DateTime in WCF query with Azure Table Storage

Question

So, a quick overview of what I'm doing: We're currently storing events to Azure Table storage from a Node.js cloud service using the "azure-storage" npm module. We're storing our own timestamps for these events in storage (as opposed to using the Azure defined one).

Now, we have coded a generic storage handler script that for the moment just stores all values as strings. To save refactoring this script, I was hoping there would be a way to tweak the query instead.

So, my question is, is it possible to query by datetime where the stored value is not actually a datetime field and instead a string?

My original query included the following:

.where( "_timestamp ge datetime'?'", timestamp );

In the above code I need to somehow have the query treat _timestamp as a datetime instead of a string...

Would something like the following work, or what's the best way to do it?

.where( "datetime _timestamp ge datetime'?'", timestamp );

Answer 1

AFAIK, if the attribute type is String in an Azure Table, you can't convert that to DateTime . Thus you won't be able to use .where( "_timestamp ge datetime'?'", timestamp );

If you're storing your _timestamp in yyyy-MM-ddTHH:mm:ssZ format, then you could simply do a string based query like

.where( "_timestamp ge '?'", timestamp );

and that should work just fine other than the fact that this query is going to do a full table scan and will not be an optimized query. However if you're storing in some other format, you may get different results.