Jstl Sql Update Tag

<sql:update> Tag

JSP Standard Tag Library

The <sql:update> tag is used to execute an SQL statement that does not return a ResultSet object, such as SQL INSERT, UPDATE, or DELETE statements.

Syntax Format

<sql:update var="<string>" scope="<string>" sql="<string>" dataSource="<string>"/>

Attributes

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

Attribute	Description	Required	Default
sql	The SQL command to be executed (does not return a ResultSet object).	No	Body
dataSource	The database connection to use (overrides the default).	No	Default database
var	The variable to store the number of affected rows.	No	None
scope	The scope of the var attribute.	No	Page

Program Example

First, you need to create an Employees table in the TEST database and add a few records to it. The specific steps are as follows:

Step 1:

Open CMD and change the directory to the installation directory:

C:>
C:>cd Program FilesMySQLbin
C:Program FilesMySQLbin>

Step 2:

C:Program FilesMySQLbin>mysql -u root -p
Enter password: ********
mysql>

Step 3:

Create the Employees table in the TEST database:

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

Create Data Records:

Finally, create a few records in the Employees table:

mysql> INSERT INTO Employees VALUES (100, 18, 'Zara', 'Ali');
Query OK, 1 row affected (0.05 sec)
 
mysql> INSERT INTO Employees VALUES (101, 25, 'Mahnaz', 'Fatma');
Query OK, 1 row affected (0.00 sec)
 
mysql> INSERT INTO Employees VALUES (102, 30, 'Zaid', 'Khan');
Query OK, 1 row affected (0.00 sec)
 
mysql> INSERT INTO Employees VALUES (103, 28, 'Sumit', 'Mittal');
Query OK, 1 row affected (0.00 sec)
 
mysql>

Now, write a JSP file that uses the <sql:update> tag to execute an SQL INSERT statement:

<%@ 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.*" %>
<%@ 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:update Tag</title>
</head>
<body>
 
<sql:setDataSource var="snapshot" driver="com.mysql.jdbc.Driver"
     url="jdbc:mysql://localhost/TEST"
     user="root"  password="pass123"/>

<sql:update dataSource="${snapshot}" var="count">
   INSERT INTO Employees VALUES (104, 2, 'Nuha', 'Ali');
</sql:update>

<sql:query dataSource="${snapshot}" var="result">
   SELECT * from Employees;
</sql:query>
 
<table border="1" width="100%">
<tr>
<th>Emp ID</th>
<th>First Name</th>
<th>Last Name</th>
<th>Age</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.age}"/></td>
</tr>
</c:forEach>
</table>

</body>
</html>

The result is as follows:

SQL UPDATE and DELETE statements are used in a similar way to the INSERT statement.

If you need to use variables in sql:update, you can use sql:param.

<sql:update dataSource="${snapshot}" var="count">
  DELETE FROM Employees WHERE Id = ?
  <sql:param value="${empId}" />
</sql:update>

JSP Standard Tag Library

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