diff --git a/src/main/java/com/microsoft/sqlserver/jdbc/SQLServerDataTable.java b/src/main/java/com/microsoft/sqlserver/jdbc/SQLServerDataTable.java
index d3f176a31..939ac5163 100644
--- a/src/main/java/com/microsoft/sqlserver/jdbc/SQLServerDataTable.java
+++ b/src/main/java/com/microsoft/sqlserver/jdbc/SQLServerDataTable.java
@@ -13,10 +13,12 @@
 import java.time.OffsetDateTime;
 import java.time.OffsetTime;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Set;
 import java.util.UUID;
 
 public final class SQLServerDataTable {
@@ -24,6 +26,7 @@ public final class SQLServerDataTable {
     int rowCount = 0;
     int columnCount = 0;
     Map<Integer, SQLServerDataColumn> columnMetadata = null;
+    Set<String> columnList = null;
     Map<Integer, Object[]> rows = null;
 
     private String tvpName = null;
@@ -37,6 +40,7 @@ public final class SQLServerDataTable {
     // Name used in CREATE TYPE
     public SQLServerDataTable() throws SQLServerException {
         columnMetadata = new LinkedHashMap<>();
+        columnList = new HashSet<>();
         rows = new HashMap<>();
     }
 
@@ -75,7 +79,7 @@ public synchronized Iterator<Entry<Integer, Object[]>> getIterator() {
     public synchronized void addColumnMetadata(String columnName,
             int sqlType) throws SQLServerException {
         // column names must be unique
-        Util.checkDuplicateColumnName(columnName, columnMetadata);
+        checkDuplicateColumnName(columnName);
         columnMetadata.put(columnCount++, new SQLServerDataColumn(columnName, sqlType));
     }
 
@@ -89,10 +93,29 @@ public synchronized void addColumnMetadata(String columnName,
      */
     public synchronized void addColumnMetadata(SQLServerDataColumn column) throws SQLServerException {
         // column names must be unique
-        Util.checkDuplicateColumnName(column.columnName, columnMetadata);
+        checkDuplicateColumnName(column.columnName);
         columnMetadata.put(columnCount++, column);
     }
 
+    /**
+     * Checks if duplicate columns exists, in O(n) time.
+     * 
+     * @param columnName
+     *            the name of the column
+     * @throws SQLServerException
+     *             when a duplicate column exists
+     */
+    private void checkDuplicateColumnName(String columnName) throws SQLServerException {
+        if (null != columnList) {
+            //columnList.add will return false if the same column name already exists
+            if (!columnList.add(columnName)) {
+                MessageFormat form = new MessageFormat(SQLServerException.getErrString("R_TVPDuplicateColumnName"));
+                Object[] msgArgs = {columnName};
+                throw new SQLServerException(null, form.format(msgArgs), null, 0, false);
+            }
+        }
+    }
+
     /**
      * Adds one row of data to the data table.
      *