I am trying to add a feature class in ArcMap from SDE database. I am using SQL SERVER 2008R2 and ArcGIS 10.1. I made a multiple polygons union in to one polygon using STUnion() function. The 'UNION' process seems to work OK, and I can preview the spatial data on SQL Server Management Studio although the unioned polygon are not clean inside very much. However, I can not preview the features and the data in ArcCatalog, ArcMap, and open the properties. when I try and add the data to an ArcGIS project I get the following error:
Open Failed Error opening feature class Invalid entity type. Invalid entity type.
I have checked that all my fields allow null values. Everything seems fine. Any thoughts?