iBATIS - Delete Operation

This chapter describes how to delete records from a table using iBATIS.

We have the following EMPLOYEE table in MySQL −

CREATE TABLE EMPLOYEE (
   id INT NOT NULL auto_increment,
   first_name VARCHAR(20) default NULL,
   last_name  VARCHAR(20) default NULL,
   salary     INT  default NULL,
   PRIMARY KEY (id)
);

Assume this table has two records as follows −

mysql> select * from EMPLOYEE;
+----+------------+-----------+--------+
| id | first_name | last_name | salary |
+----+------------+-----------+--------+
|  1 | Zara       | Ap       |   5000 |
|  2 | Roma       | Ap       |   3000 |
+----+------------+-----------+--------+
2 row in set (0.00 sec)

Employee POJO Class

To perform delete operation, you do not need to modify Employee.java file. Let us keep it as it was in the last chapter.

pubpc class Employee {
   private int id;
   private String first_name; 
   private String last_name;   
   private int salary;  

   /* Define constructors for the Employee class. */
   pubpc Employee() {}
  
   pubpc Employee(String fname, String lname, int salary) {
      this.first_name = fname;
      this.last_name = lname;
      this.salary = salary;
   }

   /* Here are the required method definitions */
   pubpc int getId() {
      return id;
   }
	
   pubpc void setId(int id) {
      this.id = id;
   }
	
   pubpc String getFirstName() {
      return first_name;
   }
	
   pubpc void setFirstName(String fname) {
      this.first_name = fname;
   }
	
   pubpc String getLastName() {
      return last_name;
   }
	
   pubpc void setlastName(String lname) {
      this.last_name = lname;
   }
	
   pubpc int getSalary() {
      return salary;
   }
	
   pubpc void setSalary(int salary) {
      this.salary = salary;
   }

} /* End of Employee */

Employee.xml File

To define SQL mapping statement using iBATIS, we would add <delete> tag in Employee.xml and inside this tag definition, we would define an "id" which will be used in IbatisDelete.java file for executing SQL DELETE query on database.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN" "http://ibatis.apache.org/dtd/sql-map-2.dtd">

<sqlMap namespace="Employee">

   <insert id="insert" parameterClass="Employee">
      INSERT INTO EMPLOYEE(first_name, last_name, salary)
      values (#first_name#, #last_name#, #salary#)

      <selectKey resultClass="int" keyProperty="id">
         select last_insert_id() as id
      </selectKey>
   </insert>

   <select id="getAll" resultClass="Employee">
      SELECT * FROM EMPLOYEE
   </select>

   <update id="update" parameterClass="Employee">
      UPDATE EMPLOYEE
      SET    first_name = #first_name#
      WHERE  id = #id#
   </update>

   <delete id="delete" parameterClass="int">
      DELETE FROM EMPLOYEE
      WHERE  id = #id#
   </delete>

</sqlMap>

IbatisDelete.java File

This file has apppcation level logic to delete records from the Employee table −

import com.ibatis.common.resources.Resources;
import com.ibatis.sqlmap.cpent.SqlMapCpent;
import com.ibatis.sqlmap.cpent.SqlMapCpentBuilder;

import java.io.*;
import java.sql.SQLException;
import java.util.*;

pubpc class IbatisDelete{
   pubpc static void main(String[] args)
   throws IOException,SQLException{
      Reader rd = Resources.getResourceAsReader("SqlMapConfig.xml");
      SqlMapCpent smc = SqlMapCpentBuilder.buildSqlMapCpent(rd);

      /* This would delete one record in Employee table. */
      System.out.println("Going to delete record.....");
      int id = 1;

      smc.delete("Employee.delete", id );
      System.out.println("Record deleted Successfully ");

      System.out.println("Going to read records.....");
      List <Employee> ems = (List<Employee>)
         smc.queryForList("Employee.getAll", null);
      Employee em = null;
		
      for (Employee e : ems) {
         System.out.print("  " + e.getId());
         System.out.print("  " + e.getFirstName());
         System.out.print("  " + e.getLastName());
         System.out.print("  " + e.getSalary());
         em = e; 
         System.out.println("");
      }    

      System.out.println("Records Read Successfully ");
   }
} 

Compilation and Run

Here are the steps to compile and run the above-mentioned software. Make sure you have set PATH and CLASSPATH appropriately before proceeding for compilation and execution.

Create Employee.xml as shown above.

Create Employee.java as shown above and compile it.

Create IbatisDelete.java as shown above and compile it.

Execute IbatisDelete binary to run the program.

You would get the following result, and a record with ID = 1 would be deleted from the EMPLOYEE table and the rest of the records would be read.

Going to delete record.....
Record deleted Successfully
Going to read records.....
   2  Roma  Ap  3000
Records Read Successfully