improve wall filter

src/main/java/com/alibaba/druid/sql/ast/expr/SQLPropertyExpr.java

@@ -28,7 +28,9 @@ public class SQLPropertyExpr extends SQLExprImpl implements SQLName {
     private String            name;
 
     public SQLPropertyExpr(SQLExpr owner, String name){
-
+        if (owner != null) {
+            owner.setParent(this);
+        }
         this.owner = owner;
         this.name = name;
     }
@@ -46,6 +48,9 @@ public class SQLPropertyExpr extends SQLExprImpl implements SQLName {
     }
 
     public void setOwner(SQLExpr owner) {
+        if (owner != null) {
+            owner.setParent(this);
+        }
         this.owner = owner;
     }
 

src/main/java/com/alibaba/druid/sql/ast/statement/SQLAlterTableStatement.java

@@ -20,6 +20,8 @@ import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLName;
 import com.alibaba.druid.sql.ast.SQLStatementImpl;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitor;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class SQLAlterTableStatement extends SQLStatementImpl implements SQLDDLStatement {
 
@@ -54,4 +56,13 @@ public class SQLAlterTableStatement extends SQLStatementImpl implements SQLDDLSt
     public void setName(SQLName name) {
         this.setTableSource(new SQLExprTableSource(name));
     }
+    
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, getTableSource());
+            acceptChild(visitor, getItems());
+        }
+        visitor.endVisit(this);
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/statement/SQLDeleteStatement.java

@@ -44,6 +44,9 @@ public class SQLDeleteStatement extends SQLStatementImpl {
     }
 
     public void setTableSource(SQLTableSource tableSource) {
+        if (tableSource != null) {
+            tableSource.setParent(this);
+        }
         this.tableSource = tableSource;
     }
 

src/main/java/com/alibaba/druid/sql/ast/statement/SQLInsertInto.java

@@ -49,6 +49,9 @@ public abstract class SQLInsertInto extends SQLObjectImpl {
     }
 
     public void setTableSource(SQLExprTableSource tableSource) {
+        if (tableSource != null) {
+            tableSource.setParent(this);
+        }
         this.tableSource = tableSource;
     }
 

src/main/java/com/alibaba/druid/sql/ast/statement/SQLJoinTableSource.java

@@ -63,6 +63,9 @@ public class SQLJoinTableSource extends SQLTableSourceImpl {
     }
 
     public void setLeft(SQLTableSource left) {
+        if (left != null) {
+            left.setParent(this);
+        }
         this.left = left;
     }
 
@@ -71,6 +74,9 @@ public class SQLJoinTableSource extends SQLTableSourceImpl {
     }
 
     public void setRight(SQLTableSource right) {
+        if (right != null) {
+            right.setParent(this);
+        }
         this.right = right;
     }
 
@@ -79,6 +85,9 @@ public class SQLJoinTableSource extends SQLTableSourceImpl {
     }
 
     public void setCondition(SQLExpr condition) {
+        if (condition != null) {
+            condition.setParent(this);
+        }
         this.condition = condition;
     }
 

src/main/java/com/alibaba/druid/sql/ast/statement/SQLSelectQueryBlock.java

@@ -43,10 +43,13 @@ public class SQLSelectQueryBlock extends SQLSelectQuery {
     }
 
     public void setInto(SQLExpr into) {
-        this.into = new SQLExprTableSource(into);
+        this.setInto(new SQLExprTableSource(into));
     }
 
     public void setInto(SQLExprTableSource into) {
+        if (into != null) {
+            into.setParent(this);
+        }
         this.into = into;
     }
 

src/main/java/com/alibaba/druid/sql/ast/statement/SQLTruncateStatement.java

@@ -36,7 +36,9 @@ public class SQLTruncateStatement extends SQLStatementImpl {
     }
     
     public void addTableSource(SQLName name) {
-        this.tableSources.add(new SQLExprTableSource(name));
+        SQLExprTableSource tableSource = new SQLExprTableSource(name);
+        tableSource.setParent(this);
+        this.tableSources.add(tableSource);
     }
 
     @Override

src/main/java/com/alibaba/druid/sql/ast/statement/SQLUpdateStatement.java

@@ -45,6 +45,9 @@ public class SQLUpdateStatement extends SQLStatementImpl {
     }
 
     public void setTableSource(SQLTableSource tableSource) {
+        if (tableSource != null) {
+            tableSource.setParent(this);
+        }
         this.tableSource = tableSource;
     }