diff --git a/pom.xml b/pom.xml
index 0e19bbf..ca1e6c5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -8,7 +8,7 @@
 
   <groupId>vavi</groupId>
   <artifactId>vavi-sql-mdb</artifactId>
-  <version>0.0.7</version>
+  <version>0.0.8</version>
 
   <name>Vavi SQL MDB API</name>
   <organization>
diff --git a/src/main/java/vavi/sql/EngineBase.java b/src/main/java/vavi/sql/EngineBase.java
index 98fc7af..4945375 100644
--- a/src/main/java/vavi/sql/EngineBase.java
+++ b/src/main/java/vavi/sql/EngineBase.java
@@ -59,7 +59,7 @@ public String columnNameAt(int index) {
     protected boolean isSelectAll;
 
     /** values set by a prepared statement */
-    protected Map<Integer, Object> params;
+    private Map<Integer, Object> params;
 
     /** table name and columns name, type and value */
     private ResultSettable database;
@@ -184,7 +184,12 @@ public Function<Object[], Object> eval(Phrase... prims) {
         }
     }
 
-    /** engine specific routine */
+    /**
+     * engine specific routine
+     * @after {@link #isSelect}
+     * @after {@link #table}
+     * @after {@link #whereClause}
+     */
     protected abstract void executeInternal(String sql) throws IOException;
 
     @Override
@@ -200,14 +205,11 @@ public boolean execute(String sql) throws IOException {
         }
     }
 
-    /** engine specific routine */
-    protected abstract void executeInternal(String sql, Map<Integer, Object> params) throws IOException;
-
     @Override
     public boolean execute(String sql, Map<Integer, Object> params) throws IOException {
         this.params = params;
 
-        executeInternal(sql, params);
+        executeInternal(sql);
 
         // rpn
         Deque<EngineBase.Phrase> stack = new ArrayDeque<>();
diff --git a/src/main/java/vavi/sql/JSqlParserEngine.java b/src/main/java/vavi/sql/JSqlParserEngine.java
index 59d24d5..470d791 100644
--- a/src/main/java/vavi/sql/JSqlParserEngine.java
+++ b/src/main/java/vavi/sql/JSqlParserEngine.java
@@ -11,7 +11,6 @@
 import java.io.StringReader;
 import java.lang.System.Logger.Level;
 import java.util.List;
-import java.util.Map;
 
 import net.sf.jsqlparser.JSQLParserException;
 import net.sf.jsqlparser.expression.Alias;
@@ -66,21 +65,6 @@ protected void executeInternal(String sql) throws IOException {
         }
     }
 
-    @Override
-    protected void executeInternal(String sql, Map<Integer, Object> params) throws IOException {
-        try {
-            this.params = params;
-
-            Reader reader = new StringReader(sql);
-            net.sf.jsqlparser.statement.Statement statement = parser.parse(reader);
-logger.log(Level.TRACE, "statement: " + statement);
-
-            statement.accept(statementVisitor);
-        } catch (JSQLParserException e) {
-            throw new IOException(e);
-        }
-    }
-
     /** */
     private final SelectVisitor selectVisitor = new SelectVisitorAdapter() {