diff --git a/src/main/java/com/alibaba/druid/mapping/MappingEngine.java b/src/main/java/com/alibaba/druid/mapping/MappingEngine.java
index d720a7e200..884c33cdbd 100644
--- a/src/main/java/com/alibaba/druid/mapping/MappingEngine.java
+++ b/src/main/java/com/alibaba/druid/mapping/MappingEngine.java
@@ -38,7 +38,13 @@ public class MappingEngine {
         this.provider = provider;
     }
 
-    public Entity getFirstEntity() {
+    public Entity getFirstEntity(MappingContext context) {
+        Entity entity = context.getDefaultEntity();
+        
+        if (entity != null) {
+            return entity;
+        }
+        
         for (Map.Entry<String, Entity> entry : entities.entrySet()) {
             return entry.getValue();
         }
@@ -110,6 +116,10 @@ public class MappingEngine {
 
         return toSQL(stmt);
     }
+    
+    public SQLSelectQueryBlock explainToSelectSQLObject(String sql) {
+        return explainToSelectSQLObject(sql, new MappingContext());
+    }
 
     public SQLSelectQueryBlock explainToSelectSQLObject(String sql, MappingContext context) {
         return provider.explainToSelectSQLObject(this, sql, context);
diff --git a/src/main/java/com/alibaba/druid/mapping/spi/MSSQLServerMappingProvider.java b/src/main/java/com/alibaba/druid/mapping/spi/MSSQLServerMappingProvider.java
index f0802f48b4..c8612669d6 100644
--- a/src/main/java/com/alibaba/druid/mapping/spi/MSSQLServerMappingProvider.java
+++ b/src/main/java/com/alibaba/druid/mapping/spi/MSSQLServerMappingProvider.java
@@ -64,7 +64,7 @@ public class MSSQLServerMappingProvider implements MappingProvider {
         SQLServerStatementParser parser = new SQLServerStatementParser(sql);
         SQLDeleteStatement stmt = parser.parseDeleteStatement();
 
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
 
         return stmt;
     }
@@ -73,7 +73,7 @@ public class MSSQLServerMappingProvider implements MappingProvider {
         SQLServerStatementParser parser = new SQLServerStatementParser(sql);
         SQLUpdateStatement stmt = parser.parseUpdateStatement();
 
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
 
         return stmt;
     }
@@ -82,7 +82,7 @@ public class MSSQLServerMappingProvider implements MappingProvider {
         SQLServerStatementParser parser = new SQLServerStatementParser(sql);
         SQLInsertStatement stmt = (SQLInsertStatement) parser.parseInsert();
 
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
 
         return stmt;
     }
diff --git a/src/main/java/com/alibaba/druid/mapping/spi/MappingVisitorUtils.java b/src/main/java/com/alibaba/druid/mapping/spi/MappingVisitorUtils.java
index 77438b7809..d0ffb087dc 100644
--- a/src/main/java/com/alibaba/druid/mapping/spi/MappingVisitorUtils.java
+++ b/src/main/java/com/alibaba/druid/mapping/spi/MappingVisitorUtils.java
@@ -5,6 +5,7 @@ import java.util.Map;
 
 import com.alibaba.druid.mapping.DruidMappingException;
 import com.alibaba.druid.mapping.Entity;
+import com.alibaba.druid.mapping.MappingContext;
 import com.alibaba.druid.mapping.MappingEngine;
 import com.alibaba.druid.mapping.Property;
 import com.alibaba.druid.sql.ast.SQLExpr;
@@ -410,7 +411,7 @@ public class MappingVisitorUtils {
         }
 
         if (x.getFrom() == null) {
-            Entity firstEntity = visitor.getEngine().getFirstEntity();
+            Entity firstEntity = visitor.getEngine().getFirstEntity(visitor.getContext());
             SQLExprTableSource from = new SQLExprTableSource(new SQLIdentifierExpr(firstEntity.getName()));
             from.putAttribute(MAPPING_ENTITY, firstEntity);
             x.setFrom(from);
@@ -470,23 +471,23 @@ public class MappingVisitorUtils {
         return entity;
     }
 
-    public static void setTableSource(MappingEngine engine, SQLDeleteStatement stmt) {
+    public static void setTableSource(MappingEngine engine, SQLDeleteStatement stmt, MappingContext context) {
         if (stmt.getExprTableSource() == null) {
-            Entity entity = engine.getFirstEntity();
+            Entity entity = engine.getFirstEntity(context);
             stmt.setTableSource(new SQLIdentifierExpr(entity.getName()));
         }
     }
 
-    public static void setTableSource(MappingEngine engine, SQLUpdateStatement stmt) {
+    public static void setTableSource(MappingEngine engine, SQLUpdateStatement stmt, MappingContext context) {
         if (stmt.getTableSource() == null) {
-            Entity entity = engine.getFirstEntity();
+            Entity entity = engine.getFirstEntity(context);
             stmt.setTableSource(new SQLIdentifierExpr(entity.getName()));
         }
     }
 
-    public static void setTableSource(MappingEngine engine, SQLInsertStatement stmt) {
+    public static void setTableSource(MappingEngine engine, SQLInsertStatement stmt, MappingContext context) {
         if (stmt.getTableSource() == null) {
-            Entity entity = engine.getFirstEntity();
+            Entity entity = engine.getFirstEntity(context);
             stmt.setTableSource(new SQLIdentifierExpr(entity.getName()));
         }
     }
diff --git a/src/main/java/com/alibaba/druid/mapping/spi/MySqlMappingProvider.java b/src/main/java/com/alibaba/druid/mapping/spi/MySqlMappingProvider.java
index 55ed45833f..2bcf0b6c21 100644
--- a/src/main/java/com/alibaba/druid/mapping/spi/MySqlMappingProvider.java
+++ b/src/main/java/com/alibaba/druid/mapping/spi/MySqlMappingProvider.java
@@ -64,7 +64,7 @@ public class MySqlMappingProvider implements MappingProvider {
         MySqlStatementParser parser = new MySqlStatementParser(sql);
 
         MySqlDeleteStatement stmt = parser.parseDeleteStatement();
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
 
         return stmt;
     }
@@ -73,7 +73,7 @@ public class MySqlMappingProvider implements MappingProvider {
         MySqlStatementParser parser = new MySqlStatementParser(sql);
         SQLUpdateStatement stmt = parser.parseUpdateStatement();
 
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
 
         return stmt;
     }
@@ -82,7 +82,7 @@ public class MySqlMappingProvider implements MappingProvider {
         MySqlStatementParser parser = new MySqlStatementParser(sql);
         SQLInsertStatement stmt = (SQLInsertStatement) parser.parseInsert();
 
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
 
         return stmt;
     }
diff --git a/src/main/java/com/alibaba/druid/mapping/spi/OracleMappingProvider.java b/src/main/java/com/alibaba/druid/mapping/spi/OracleMappingProvider.java
index 41c09a16f6..5d27432944 100644
--- a/src/main/java/com/alibaba/druid/mapping/spi/OracleMappingProvider.java
+++ b/src/main/java/com/alibaba/druid/mapping/spi/OracleMappingProvider.java
@@ -45,7 +45,7 @@ public class OracleMappingProvider implements MappingProvider {
         OracleStatementParser parser = new OracleStatementParser(sql);
         OracleDeleteStatement stmt = parser.parseDeleteStatement();
 
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
 
         return stmt;
     }
@@ -54,7 +54,7 @@ public class OracleMappingProvider implements MappingProvider {
         OracleStatementParser parser = new OracleStatementParser(sql);
         SQLUpdateStatement stmt = parser.parseUpdateStatement();
 
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
 
         return stmt;
     }
@@ -62,7 +62,7 @@ public class OracleMappingProvider implements MappingProvider {
     public SQLInsertStatement explainToInsertSQLObject(MappingEngine engine, String sql, MappingContext context) {
         OracleStatementParser parser = new OracleStatementParser(sql);
         SQLInsertStatement stmt = (SQLInsertStatement) parser.parseInsert();
-        MappingVisitorUtils.setTableSource(engine, stmt);
+        MappingVisitorUtils.setTableSource(engine, stmt, context);
         return stmt;
 
     }