JSTL SQL <sql:transaction> Tag

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The <sql:transaction> tag is used to group <sql:query> and <sql:update> into transactions. You can put as many <sql:query> and <sql:update> as statements inside <sql:transaction> to make them a single transaction.

It ensures that the database modifications performed by the nested actions are either committed or rolled back if an exception is thrown by any nested action.

Attribute:

The <sql:transaction> tag has following attributes:

AttributeDescription RequiredDefault
dataSourceDatabase connection to use (overrides the default)NoDefault database
isolationTransaction isolation (READ_COMMITTED, READ_UNCOMMITTED, REPEATABLE_READ, or SERIALIZABLE)NoDatabase’s default

Example:

To start with basic concept, let us create a simple table Students table in TEST database and create few records in that table as follows:

Step 1:

Open a Command Prompt and change to the installation directory as follows:

C:\>
C:\>cd Program Files\MySQL\bin
C:\Program Files\MySQL\bin>

Step 2:

Login to database as follows

C:\Program Files\MySQL\bin>mysql -u root -p
Enter password: ********
mysql>

Step 3:

Create the table Employee in TEST database as follows:

mysql> use TEST;
mysql> create table Students
    (
     id int not null,
     first varchar (255),
     last varchar (255),
     dob date
    );
Query OK, 0 rows affected (0.08 sec)
mysql>

Create Data Records

Finally you create few records in Employee table as follows:

mysql> INSERT INTO Students 
          VALUES (100, 'Zara', 'Ali', '2002/05/16');
Query OK, 1 row affected (0.05 sec)
 
mysql> INSERT INTO Students 
          VALUES (101, 'Mahnaz', 'Fatma', '1978/11/28');
Query OK, 1 row affected (0.00 sec)
 
mysql> INSERT INTO Students 
          VALUES (102, 'Zaid', 'Khan', '1980/10/10');
Query OK, 1 row affected (0.00 sec)
 
mysql> INSERT INTO Students 
          VALUES (103, 'Sumit', 'Mittal', '1971/05/08');
Query OK, 1 row affected (0.00 sec)
 
mysql>

Now let us write a JSP which will make use of <sql:update> along with <sql:transaction> to execute a SQL UPDATE statement. Here code inside <sql:transaction> either would be exeucted completely or not at all:

<%@ page import="java.io.*,java.util.*,java.sql.*"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*"%>
<%@ page import="java.util.Date,java.text.*" %>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql"%>
 
<html>
<head>
<title>JSTL sql:transaction Tag</title>
</head>
<body>
 
<sql:setDataSource var="snapshot" driver="com.mysql.jdbc.Driver"
     url="jdbc:mysql://localhost/TEST"
     user="root"  password="cohondob"/>

<%
Date DoB = new Date("2001/12/16");
int studentId = 100;
%>

<sql:transaction dataSource="${snapshot}">
   <sql:update var="count">
      UPDATE Students SET last = 'Ali' WHERE Id = 102
   </sql:update>
   <sql:update var="count">
      UPDATE Students SET last = 'Shah' WHERE Id = 103
   </sql:update>
   <sql:update var="count">
     INSERT INTO Students 
     VALUES (104,'Nuha', 'Ali', '2010/05/26');
   </sql:update>
</sql:transaction>

<sql:query dataSource="${snapshot}" var="result">
   SELECT * from Students;
</sql:query>
 
<table border="1" width="100%">
<tr>
<th>Emp ID</th>
<th>First Name</th>
<th>Last Name</th>
<th>DoB</th>
</tr>
<c:forEach var="row" items="${result.rows}">
<tr>
<td><c:out value="${row.id}"/></td>
<td><c:out value="${row.first}"/></td>
<td><c:out value="${row.last}"/></td>
<td><c:out value="${row.dob}"/></td>
</tr>
</c:forEach>
</table>
 
</body>
</html>

Now try to access above JSP, which should display the following result:

Emp ID First Name Last Name DoB
100 Zara Ali 2001-12-16
101 Mahnaz Fatma 1978-11-28
102 Zaid Ali 1980-10-10
103 Sumit Shah 1971-05-08
104 Nuha Ali 2010-05-26


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