I have entity mapped from a view, it appears to create a field of type int but the actual database field is bigint.

Using v2.6

You can select long/Int64 as the Type for this field. Designer => Edit Entity => Fields Tab

Also you might try to refresh the catalog, and you might need to install the latest release of v.2.6

ref: http://www.llblgen.com/tinyforum/Messages.aspx?ThreadID=19512