diff --git a/pom.xml b/pom.xml
index f4c48bd..f8df332 100644
--- a/pom.xml
+++ b/pom.xml
@@ -13,7 +13,7 @@
     <groupId>com.loafle</groupId>
     <artifactId>overflow_jpa_base_dao</artifactId>
     <packaging>jar</packaging>
-    <version>1.0.0-RELEASE</version>
+    <version>1.0.0-SNAPSHOT</version>
 
     <dependencies>
         <dependency>
diff --git a/src/main/java/com/loafle/overflow/commons/dao/JPABaseDAO.java b/src/main/java/com/loafle/overflow/commons/dao/JPABaseDAO.java
index 53524a8..30181bb 100644
--- a/src/main/java/com/loafle/overflow/commons/dao/JPABaseDAO.java
+++ b/src/main/java/com/loafle/overflow/commons/dao/JPABaseDAO.java
@@ -1,6 +1,7 @@
 package com.loafle.overflow.commons.dao;
 
 import javax.persistence.EntityManager;
+import javax.persistence.EntityTransaction;
 import javax.persistence.Persistence;
 import javax.persistence.PersistenceContext;
 import java.lang.reflect.ParameterizedType;
@@ -23,28 +24,47 @@ public class JPABaseDAO<T> implements BaseDAO<T>  {
         return this.entityManager;
     }
 
-    public T find(T entity)
-    {
-        return this.entityManager.find(entityType, entity);
+    public T find(String id) {
+        return this.entityManager.find(this.entityType, Long.parseLong(id));
     }
 
     public T create(T entity) {
-        this.entityManager.getTransaction().begin();
-        this.entityManager.persist(entity);
-        this.entityManager.getTransaction().commit();
+        EntityTransaction tx = this.entityManager.getTransaction();
+        if (!tx.isActive()) tx.begin();
+        try {
+            this.entityManager.persist(entity);
+            tx.commit();
+        }catch(Exception e) {
+            tx.rollback();
+            return null;
+        }
         return entity;
     }
 
     public T update(T entity) {
-        this.entityManager.getTransaction().begin();
-        T result = this.entityManager.merge(entity);
-        this.entityManager.getTransaction().commit();
-        return result;
+        EntityTransaction tx = this.entityManager.getTransaction();
+        if (!tx.isActive()) tx.begin();
+        try {
+            T result = this.entityManager.merge(entity);
+            tx.commit();
+            return result;
+        }catch(Exception e) {
+            tx.rollback();
+            return null;
+        }
     }
 
-    public void delete(T entity) {
-        this.entityManager.getTransaction().begin();
-        this.entityManager.remove(entityManager.contains(entity) ? entity : entityManager.merge(entity));
-        this.entityManager.getTransaction().commit();
+    public String delete(T entity) {
+        EntityTransaction tx = this.entityManager.getTransaction();
+        if (!tx.isActive()) tx.begin();
+        try {
+            this.entityManager.remove(entityManager.contains(entity) ? entity : entityManager.merge(entity));
+            tx.commit();
+            return "Success";
+        }catch(Exception e) {
+            tx.rollback();
+            return "Fail";
+        }
+
     }
 }