diff --git a/panda-jdbc/src/main/java/org/panda/jdbc/sql/AbstractDbBuiler.java b/panda-jdbc/src/main/java/org/panda/jdbc/sql/AbstractDbBuiler.java
index 0944419..308f510 100644
--- a/panda-jdbc/src/main/java/org/panda/jdbc/sql/AbstractDbBuiler.java
+++ b/panda-jdbc/src/main/java/org/panda/jdbc/sql/AbstractDbBuiler.java
@@ -93,7 +93,6 @@ public abstract class AbstractDbBuiler {
         sql=sql.toLowerCase();
         if (sql.lastIndexOf("order")>sql.lastIndexOf(")")){
             sb.append(sql.substring(sql.indexOf("from")+4,sql.lastIndexOf("order")));
-
         }else{
             sb.append(sql.substring(sql.indexOf("from")+4));
         }
diff --git a/panda-jdbc/src/main/java/org/panda/jdbc/sql/BeanSqlUtil.java b/panda-jdbc/src/main/java/org/panda/jdbc/sql/BeanSqlUtil.java
index 19e341a..c75c293 100644
--- a/panda-jdbc/src/main/java/org/panda/jdbc/sql/BeanSqlUtil.java
+++ b/panda-jdbc/src/main/java/org/panda/jdbc/sql/BeanSqlUtil.java
@@ -15,6 +15,8 @@ import java.util.Map;
  */
 public class BeanSqlUtil {
 
+    public static final String SQL_CHARACTER = "_";
+
     /**
      *  大小写转化驼峰
      * @param str
@@ -23,13 +25,13 @@ public class BeanSqlUtil {
     public  static String caseToHump(String str){
         StringBuffer strBuffer=new StringBuffer();
         char[] charArray=str.toCharArray();
-        for (int i=0;i<charArray.length;i++){
+        for (int i=0,charArrayLenght=charArray.length;i<charArrayLenght;i++){
             if (i==0){
                 strBuffer.append(charArray[i]);
                 continue;
             }
             if (Character.isUpperCase(charArray[i])){
-                strBuffer.append("_"+charArray[i]);
+                strBuffer.append(SQL_CHARACTER+charArray[i]);
             }else {
                 strBuffer.append(charArray[i]);
             }
@@ -46,7 +48,7 @@ public class BeanSqlUtil {
         StringBuffer strBuffer=new StringBuffer();
         char[] charArray=str.toCharArray();
         for (int i=0;i<charArray.length;i++){
-            if (charArray[i] == '_'){
+            if (SQL_CHARACTER.equals(charArray[i])){
                 i++;
                 strBuffer.append(Character.toUpperCase(charArray[i]));
             }else {
diff --git a/panda-jdbc/src/main/java/org/panda/jdbc/sql/MysqlBuilder.java b/panda-jdbc/src/main/java/org/panda/jdbc/sql/MysqlBuilder.java
index 1fb90ab..87d939b 100644
--- a/panda-jdbc/src/main/java/org/panda/jdbc/sql/MysqlBuilder.java
+++ b/panda-jdbc/src/main/java/org/panda/jdbc/sql/MysqlBuilder.java
@@ -81,12 +81,9 @@ public class MysqlBuilder extends AbstractDbBuiler {
                 }
             });
         }
-
         map.forEach((key,value)->{
             sql.append(createTableStr(value));
         });
-
-
         return sql.toString();
     }
 
@@ -122,7 +119,7 @@ public class MysqlBuilder extends AbstractDbBuiler {
             sql.append(",");
         }
         sql.append("primary key(id)");
-        sql.append(")ENGINE=MyISAM DEFAULT CHARSET=utf8;");
+        sql.append(")ENGINE=Innodb DEFAULT CHARSET=utf8;");
 
         return sql.toString();
     }
@@ -139,7 +136,8 @@ public class MysqlBuilder extends AbstractDbBuiler {
 
         if (CollectionUtil.isEmpty(fieldMap)){
             LOGGER.error("can not insert entity:fieldMap is empty");
-            return null;
+            throw new RuntimeException("can not insert entity:fieldMap is empty");
+           // return null;
         }
         String sql = "INSERT INTO "+ BeanSqlUtil.beanNameToTableName(entityClass);
         StringBuilder columns = new StringBuilder("(");