diff --git a/hetu-oracle/src/main/java/io/hetu/core/plugin/oracle/OracleClient.java b/hetu-oracle/src/main/java/io/hetu/core/plugin/oracle/OracleClient.java
index 25184236d..3a04147b2 100644
--- a/hetu-oracle/src/main/java/io/hetu/core/plugin/oracle/OracleClient.java
+++ b/hetu-oracle/src/main/java/io/hetu/core/plugin/oracle/OracleClient.java
@@ -808,7 +808,7 @@ public class OracleClient
         return jdbcTableHandle;
     }
 
-    public void setStatement(ConnectorSession session, ConnectorTableHandle tableHandle, PreparedStatement statement, Block block, int position, int channel)
+    private void setStatement(ConnectorSession session, ConnectorTableHandle tableHandle, PreparedStatement statement, Block block, int position, int channel)
             throws SQLException
     {
         JdbcTableHandle jdbcTableHandle = (JdbcTableHandle) tableHandle;
@@ -877,8 +877,7 @@ public class OracleClient
     {
         JdbcTableHandle tableHandle = (JdbcTableHandle) handle;
         return format(
-                "DELETE FROM %s WHERE ROWID=%s",
-                quoted(tableHandle.getCatalogName(), tableHandle.getSchemaName(), tableHandle.getTableName()), "?");
+                "DELETE FROM %s WHERE ROWID=%s", tableHandle.getSchemaPrefixedTableName(), "?");
     }
 
     @Override
@@ -886,7 +885,7 @@ public class OracleClient
     {
         JdbcTableHandle tableHandle = (JdbcTableHandle) handle;
         StringBuilder sqlBuilder = new StringBuilder();
-        sqlBuilder.append(format("UPDATE %s SET ", quoted(tableHandle.getCatalogName(), tableHandle.getSchemaName(), tableHandle.getTableName())));
+        sqlBuilder.append(format("UPDATE %s SET ", tableHandle.getSchemaPrefixedTableName()));
         for (int i = 0; i < setNum; i++) {
             sqlBuilder.append(updatedColumns.get(i));
             sqlBuilder.append(" = ? ");
diff --git a/hetu-oracle/src/main/java/io/hetu/core/plugin/oracle/optimization/OracleSqlStatementWriter.java b/hetu-oracle/src/main/java/io/hetu/core/plugin/oracle/optimization/OracleSqlStatementWriter.java
index 65ddd9fec..701924e68 100644
--- a/hetu-oracle/src/main/java/io/hetu/core/plugin/oracle/optimization/OracleSqlStatementWriter.java
+++ b/hetu-oracle/src/main/java/io/hetu/core/plugin/oracle/optimization/OracleSqlStatementWriter.java
@@ -16,10 +16,6 @@ package io.hetu.core.plugin.oracle.optimization;
 
 import io.prestosql.plugin.jdbc.optimization.BaseJdbcSqlStatementWriter;
 import io.prestosql.plugin.jdbc.optimization.JdbcPushDownParameter;
-import io.prestosql.spi.sql.expression.Selection;
-
-import java.util.List;
-import java.util.StringJoiner;
 
 public class OracleSqlStatementWriter
         extends BaseJdbcSqlStatementWriter
@@ -42,32 +38,4 @@ public class OracleSqlStatementWriter
     {
         return "SELECT * FROM (" + table + ") WHERE ROWNUM <= " + count;
     }
-
-    @Override
-    public String from(String selections, String from)
-    {
-        if (from.contains(")")) {
-            return selections + " FROM " + from.substring(0, from.lastIndexOf(")"));
-        }
-        else {
-            return selections + " FROM " + from;
-        }
-    }
-
-    @Override
-    public String select(List<Selection> selections)
-    {
-        StringBuilder builder = new StringBuilder("SELECT ");
-        if (selections == null || selections.size() == 0) {
-            builder.append("null");
-        }
-        else {
-            StringJoiner joiner = new StringJoiner(", ");
-            for (Selection selection : selections) {
-                joiner.add(selection.getExpression());
-            }
-            builder.append(joiner);
-        }
-        return builder.toString();
-    }
 }