215c215
<                     type_cast_expression = "CAST(? as NVARCHAR)"
---
>                     type_cast_expression = "CAST(? as NVARCHAR(%d))" % target_column.length
228c228
<                     type_cast_expression = "CAST(? as NCHAR)"
---
>                     type_cast_expression = "CAST(? as NCHAR(%d))" % target_column.length