Analysis Services error: Errors in the back-end database access module. The size specified for a binding was too small, resulting in one or more column values being truncated.
This error occurs when the size(number of characters) of an attribute exceeds the DataSize defined in the attribute properties of the dimension. By default, Analysis Services sets the size of an attribute based on the size defined in the relational database.
For example, let’s say you have a field called CustomerID which is defined as VARCHAR(4) in the database. If you use this field as an attribute in a dimension, Analysis Services will set the DataSize property to 4. You can see this property by expanding the NameColumn and KeyColumns property of the attribute.
Now, if you replace the dimension in Analysis Services with a named query and edit the CustomerID field with something like CASE WHEN CustomerID IS NULL THEN ‘Not Defined’ ELSE CustomerID END AS CustomerID, the cube fail to process because Analysis Services has already set the data size for CustomerID to 4 but we just violated this by using the value ‘Not Defined’ which is of length 12.
To resolve this issue, all we need to do is increase the value of the property called DataSize for the attribute under both NameColumn and KeyColumns.
Hope this helps.