diff --git a/samples/features/sql-big-data-cluster/data-virtualization/oracle/customer-oracle.sql b/samples/features/sql-big-data-cluster/data-virtualization/oracle/customer-oracle.sql
index 44c3bcd3..6f308f88 100644
--- a/samples/features/sql-big-data-cluster/data-virtualization/oracle/customer-oracle.sql
+++ b/samples/features/sql-big-data-cluster/data-virtualization/oracle/customer-oracle.sql
@@ -22,23 +22,23 @@ IF NOT EXISTS(SELECT * FROM sys.external_data_sources WHERE name = 'OracleSalesS
 CREATE EXTERNAL TABLE [dbo].[customer_ora]
 (
     [C_CUSTOMER_SK] DECIMAL(10,0),
-    [C_CUSTOMER_ID] VARCHAR(16) COLLATE SQL_Latin1_General_CP1_CI_AS,
+    [C_CUSTOMER_ID] NVARCHAR(16) COLLATE SQL_Latin1_General_CP1_CI_AS,
     [C_CURRENT_CDEMO_SK] DECIMAL(10,0),
     [C_CURRENT_HDEMO_SK] DECIMAL(10,0),
     [C_CURRENT_ADDR_SK] DECIMAL(10,0),
     [C_FIRST_SHIPTO_DATE_SK] DECIMAL(10,0),
     [C_FIRST_SALES_DATE_SK] DECIMAL(8,0),
-    [C_SALUTATION] VARCHAR(10) COLLATE SQL_Latin1_General_CP1_CI_AS,
-    [C_FIRST_NAME] VARCHAR(20) COLLATE SQL_Latin1_General_CP1_CI_AS,
-    [C_LAST_NAME] VARCHAR(30) COLLATE SQL_Latin1_General_CP1_CI_AS,
-    [C_PREFERRED_CUST_FLAG] VARCHAR COLLATE SQL_Latin1_General_CP1_CI_AS,
+    [C_SALUTATION] NVARCHAR(10) COLLATE SQL_Latin1_General_CP1_CI_AS,
+    [C_FIRST_NAME] NVARCHAR(20) COLLATE SQL_Latin1_General_CP1_CI_AS,
+    [C_LAST_NAME] NVARCHAR(30) COLLATE SQL_Latin1_General_CP1_CI_AS,
+    [C_PREFERRED_CUST_FLAG] NVARCHAR COLLATE SQL_Latin1_General_CP1_CI_AS,
     [C_BIRTH_DAY] DECIMAL(8,0),
     [C_BIRTH_MONTH] DECIMAL(8,0),
     [C_BIRTH_YEAR] DECIMAL(8,0),
-    [C_BIRTH_COUNTRY] VARCHAR(20) COLLATE SQL_Latin1_General_CP1_CI_AS,
-    [C_LOGIN] VARCHAR(13) COLLATE SQL_Latin1_General_CP1_CI_AS,
-    [C_EMAIL_ADDRESS] VARCHAR(50) COLLATE SQL_Latin1_General_CP1_CI_AS,
-    [C_LAST_REVIEW_DATE] VARCHAR(20) COLLATE SQL_Latin1_General_CP1_CI_AS
+    [C_BIRTH_COUNTRY] NVARCHAR(20) COLLATE SQL_Latin1_General_CP1_CI_AS,
+    [C_LOGIN] NVARCHAR(13) COLLATE SQL_Latin1_General_CP1_CI_AS,
+    [C_EMAIL_ADDRESS] NVARCHAR(50) COLLATE SQL_Latin1_General_CP1_CI_AS,
+    [C_LAST_REVIEW_DATE] NVARCHAR(20) COLLATE SQL_Latin1_General_CP1_CI_AS
 )
 WITH (DATA_SOURCE=[OracleSalesSrvr],
       LOCATION='<oracle_service_name,nvarchar(30),xe>.SALES.CUSTOMER');