How to group queries using transaction in a JSP?

JSPJava 8Object Oriented ProgrammingProgramming

The <sql:transaction> tag is used to group the <sql:query> and <sql:update> tags into transactions. You can put as many <sql:query> and <sql:update> tags as statements inside the <sql:transaction> tag to create 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 the following attributes −

AttributeDescriptionRequiredDefault
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 the basic concept, let us create a Students table in the TEST database and create a 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 the database as follows −

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

Step 3

Create the Employee table in the 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

We will now create a few records in the 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>

Let us now write a JSP which will make use of the <sql:update> tag along with <sql:transaction> tag to execute an SQL UPDATE statement. Here the code inside <sql:transaction> tag either will be executed 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>

Access the above JSP, the following result will be displayed −

+-------------+----------------+-----------------+-----------------+
| 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          | Mittal          | 1971-05-08      |
| 104         | Nuha           | Ali             | 2010-05-26      |
+-------------+----------------+-----------------+-----------------+
raja
Published on 25-Mar-2019 06:32:23
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