This topic is about 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 | Ali | 5000 | | 2 | Roma | Ali | 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.
public class Employee {
private int id;
private String first_name;
private String last_name;
private int salary;
/* Define constructors for the Employee class. */
public Employee() {}
public Employee(String fname, String lname, int salary) {
this.first_name = fname;
this.last_name = lname;
this.salary = salary;
}
/* Here are the required method definitions */
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return first_name;
}
public void setFirstName(String fname) {
this.first_name = fname;
}
public String getLastName() {
return last_name;
}
public void setlastName(String lname) {
this.last_name = lname;
}
public int getSalary() {
return salary;
}
public 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 application level logic to delete records from the Employee table −
import com.ibatis.common.resources.Resources;
import com.ibatis.sqlmap.client.SqlMapClient;
import com.ibatis.sqlmap.client.SqlMapClientBuilder;
import java.io.*;
import java.sql.SQLException;
import java.util.*;
public class IbatisDelete{
public static void main(String[] args)
throws IOException,SQLException{
Reader rd = Resources.getResourceAsReader("SqlMapConfig.xml");
SqlMapClient smc = SqlMapClientBuilder.buildSqlMapClient(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 Ali 3000
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