A DBML generated with VisualStudio may have Columns without Member attribute, in this case DMetal crashes. When Member is not specified this is the Name attribute that must be used.
Moreover, when using a custom class to match SQL type, the attribute Type is not recognized by DBMetal. In CodeDomGenerator.GenerateTableClass() the fieldType is null.
When creating the CodeBinaryOperatorExpression condition we can test if fieldType is null and if column type's name stars with "global".