try to stop thinking in terms of SQL, if you can - although they call it GQL it's only superficially similar. One particularly big gotcha is that you can only r

try to stop thinking in terms of SQL, if you can - although they call it GQL it's only superficially similar. One particularly big gotcha is that you can only return keys or whole objects in your queries, and if you return an object it has to deserialize all the data associated with that object, so think twice before storing binary data against a frequently queried object - look to the BlobStore (this is NOT the same as a BlobProperty) or a separate object to hold larger chunks of data. This is something to consider at the get go, you'd be surprised how quickly performance degrades (ie a hundred or more items, not thousands)