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<sql:transaction> Tag

The <sql:transaction> tag is used to encapsulate <sql:query> and <sql:update> tags within a transaction. It allows multiple <sql:query> and <sql:update> operations to be grouped into a single transaction.

It ensures that modifications to the database are either committed or rolled back.

Syntax

&lt;sql:transaction dataSource="<string>" isolation="<string>"/>

Attributes

The <sql:transaction> tag has the following attributes:

Attribute	Description	Required	Default Value
dataSource	The database to be used (overrides the default)	No	Default database
isolation	Transaction isolation level (READ_COMMITTED, READ_UNCOMMITTED, REPEATABLE_READ, or SERIALIZABLE)	No	Database default

Example Demonstration

First, you need to create a table named Employees in the TEST database and add a few records to it. Follow these steps:

Step 1:

Open CMD and navigate to the installation directory:

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

Step 2:

Log into the database:

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

Step 3:

Create the Students table in the TEST database:

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, create a few records in the Students table:

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, write a JSP file to use <sql:update> and <sql:transaction> to execute an SQL UPDATE statement. The code within <sql:transaction> will either execute completely or not at all:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ 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>

&lt;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;
%>

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

&lt;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>
&lt;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>

Output:

JSP Standard Tag Library

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