Copyright © tutorialspoint.com

# JSTL SQL <sql:transaction> Tag

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:

Attribute | Description | Required | Default
--- | --- | --- | ---
dataSource | Database connection to use (overrides the default) | No | Default database
isolation | Transaction isolation (READ_COMMITTED, READ_UNCOMMITTED, REPEATABLE_READ, or SERIALIZABLE) | No | Database’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

Copyright © tutorialspoint.com