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iBatis Tutorial Part 2 – SQLMapConfig.xml Basics

admin — Wed, 13 Aug 2008 13:29:26 +0000

This is where you need to provide all configurations for iBatis. Create an XML file with name SqlMapConfig.xml

http://ibatis.apache.org/dtd/sql-map-config-2.dtd">


 value=""/> 
 

  
Lets understand the above code : 
 
type can be JDBC, JTA,External
JDBC Alias for com.ibatis.sqlmap.engine.transaction.jdbc.JdbcTrasactionConfig
JTA alias for com.ibatis.sqlmap.engine.transaction.jta.JtaTransactionConfig
External alias for com.ibatis.sqlmap.engine.transaction.external.ExternalTransactionConfig
 
datasouce can be SIMPLE, DBCP, JNDI
 SIMPLE is an alias for com.ibatis.sqlmap.engine.datasource.
SimpleDataSourceFactory DBCP is an alias for com.ibatis.sqlmap.engine.datasource.
DbcpDataSourceFactory JNDI is an alias for com.ibatis.sqlmap.engine.datasource.JndiDataSourceFactory.
While using JNDI :
Use the following code 

 
  
   
  

*  is optional
DataSource properties :

provide the driverName

provide the connection URL
 

provide the username and password
Optional properties

 
 
  
 
 


Used to add the xml where the sql queries have been written in another XML file . Should be present in the class path. Alternatively to load files from a URL  Related Articles:
Introduction to IBatis Tutorial -Part 3
IBatis vs Hibernate ? Which one to choose?



IBatis vs Hibernate ? Which one to choose?
admin — Sat, 09 Aug 2008 13:27:28 +0000
A lot of people ask me when i give sessions on IBatis.Which is better ?IBatis or Hibernate? IBatis maps the Java Objects to the SQL Query’s results. Hibernate, maps Java Objects to DB tables (Object-Relational Mapping). Hibernate automatically generates all the SQL for you. In IBatis you can directly write queried in SQL, thus if you are a good SQL programmer, you would find learning Ibatis very easy. Thus Ibatis allows you to do anything what could be done through SQL. Thus you can virtually know what the affect of a query would be.


Hibernate is excellent for CRUD queries (Create, Read, Update, Delete) queries, and in applications where the object model is already ready.



IBatis is much simpler to learn compared to Hibernate .


On the other hand, Since you need to write all the queries by yourself, It has a much steeper development time and maintainability is comparatively difficult in Ibatis.


Also if there is a change in object – model, one needs to go through all the queries and correct them, which isn’t much of a problem in hibernate.


Hibernate does not support stored procedures. Ibatis does.


IBatis is faster in terms of query processing time


IBatis is better for batch inserts queries.


IBatis is simpler.


IBatis supports Dynamic Query which Hibernates doesn’t.


Hibernate is close to Object Oriented development. Ibatis is close to relational DB.




Technorati : Hibernate, Ibatis



IBatis Tutorial – Sample Application Step 1
admin — Fri, 08 Aug 2008 13:34:19 +0000

Steps :
1) Creata a databas and a table
2) Create a package com.Employee
3) SQL mapper – Employee.xml


4) SQL configuration file : SQLMapConfig.xml
5) Create Java Application
Step 1: Create a table
use employeedb;
Query to create table :
create table employee (

employeeID integer(10) primray key auto_increment,

firstName varchar(255) not null,

lastName varchar(255) not null);
Insert some records into a table:
insert into employee(firstName,lastName,email) values

("sandeep","gupta","sonus@gmail.com");

insert into employee(firstName,lastName,email) values

("ashim","devnath","ashim@gmail.com");

insert into employee(firstName,lastName,email) values

("abhishek","kumar","abhishekmumar@gmail.com");
So now your table is ready . Lets go to Step 2
Also Read : IBatis vs Hibernate ? Which one to choose?

IBatis Tutorial – Sample Application Step 2



Ibatis Tutorial – Sample Application Step 2
admin — Fri, 08 Aug 2008 13:33:41 +0000
Step 2: Create a package and a java object .



package com.Employee

import java.io.Serializable;

public class Employee implements Serializable {

private int employeeID;


private String firstName;

private String lastName;

private String email;
public int getEmployeeID() {

return employeeID;

}

public void setEmployeeID(int employeeID) {

this.employeeID = employeeID;

}

…..
}
Similarly have a getter and setter for other attributes as well .
Also Read : IBatis vs Hibernate ? Which one to choose?

IBatis Tutorial – Sample Application Step 3

Introduction to IBatis Tutorial -Part 1



Ibatis Tutorial – Sample Application Step 3
admin — Fri, 08 Aug 2008 13:32:59 +0000


Step 3: Create struts-config.xml







PUBLIC “-//ibatis.apache.org//DTD SQL Map Config 2.0//EN”
“http://ibatis.apache.org/dtd/sql-map-config-2.dtd”>





value=”jdbc:mysql://localhost:3306/employeedb”/>












Also Read : IBatis vs Hibernate ? Which one to choose?

IBatis Tutorial – Sample Application Step 4

Introduction to IBatis Tutorial -Part 1



IBatis Tutorial – Sample Application Step 4
admin — Fri, 08 Aug 2008 13:32:10 +0000

Create Employee.xml








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>
<select id=“getEmployee” parameterClass=“int”
resultClass=“com.Contact”>
SELECT employeeID as employeeID,
firstName as firstName,
lastName as lastName,
email as email
from Employee
where employeeID=#value#
select>
<select id=“getEmployees” resultClass=“com.Employee”>
SELECT employeeID as employeeID,
firstName as firstName,
lastName as lastName,
email as email
from Employee
select>











Technorati : ibatis
Also Read : IBatis vs Hibernate ? Which one to choose?

IBatis Tutorial – Sample Application Step 5

Introduction to IBatis Tutorial -Part 1



Ibatis Tutorial – Sample Application Step 5
admin — Fri, 08 Aug 2008 13:31:25 +0000

Step 5 : Create a standalone java  class to run the application .
import java.io.Reader;

import java.util.List;
import com.ibatis.common.resources.Resources;

import  com.ibatis.sqlmap.client.SqlMapClient;

import  com.ibatis.sqlmap.client.SqlMapClientBuilder;

import com.model.Employee;
public class QueryEmployee {
public static void main(String[] args) {

try {

String resource =  “SqlMapConfig.xml”;

Reader reader = Resources.getResourceAsReader(resource);

SqlMapClient  sqlMap =

SqlMapClientBuilder.buildSqlMapClient(reader);

Integer  employeePrimaryKey = new Integer(1);

Employee employee =

(Employee)sqlMap.queryForObject(“getEmployee”,

employeePrimaryKey);

System.out.println(employee.getFirstName()

+ “\t” +  employee.getLastName());

}catch(Exception e) {

e.printStackTrace();

}

}

}



Technorati : ibatis
Also Read : IBatis vs Hibernate ? Which one to choose?

IBatis Tutorial – Sample Application Step 1





IBatis Tutorial Part 3 – SQLMapConfig.xml optional settings
admin — Fri, 08 Aug 2008 13:30:36 +0000

 Here are some of the options setting which are worth mentioning.

maxRequests ="120" 
maxSessions ="20" 
maxTransactions="10" 
lazyLoadingEnabled =" true" 
enhancementEnabled ="true" 
cacheModelsEnabled ="true" 
useStatementNamespaces ="false" 
defaultStatementTimeout ="5" />
 type ="com.Emloyee" />

Settings attributes : 
maxRequests: Maximum number of threads that can execute an SQL statement at a time
maxSessions: Number of clients that can be active at any time. 
maxTransactions: Maximum number of threads that can enter SqlMapClient.startTransactions at a time
Hint: Max Request>MaxSession >= maxTransactions
cacheModelsEnabled: This setting globally enables or disables all cache models for an SqlMapClient 
LazyLoadingEnabled: This setting globally enables or disables all lazy loading for an SqlMapClient 
enhancementEnabled: This setting enables runtime bytecode enhancements to facilitate optimized JavaBean property access as well as enhanced lazy loading
useStatementNamespaces: With this setting enabled, you must always refer to mapped statements by their fully qualified name, which is the combination of the SqlMap name and their statement name 
defaultStatementTimeout: an integer value for jdbc query timeout for all statements
Type alias : used to provide an alias name for an otherwise long java class




Introduction to IBatis Tutorial -Part 1
admin — Fri, 08 Aug 2008 13:28:35 +0000

This is a tutorial on IBatis . IBatis is a persistence framework which enables mapping SQL queries to POJOs (Plain Old Java Objects). The SQL queries are decoupled from an application by putting the queries in XML files. Mapping of the retrieved objects is automatic or semi-automatic.
IBatis couples objects with stored procedures or SQL statements using a XML descriptor.iBatis provides a set of APIs which can be used to call these statements written in an XML file. Also since IBatis gives you the power to write any SQL query in the XML file, there is nothing that IBatis cannot achieve, thus making it a very good persistence framework.IBatis is simple to learn and anyone who can write SQL queries can very well work on this. 
With IBatis you can write Inline queries, Dynamic SQL, Stored Procedures. Ibatis supports calling stored procedures directly; Also Ibatis makes sure that the SQL queries are very loosely coupled to the application code.
Ibatis also supports lazy loading, joins, and caching.
Ibatis is different as it does not bind fields to columns but binds parameters and results to the SQL statements. Also performance of IBatis is good, and it is portable across various platforms.
Click Here to download iBatis from Ibatis website. Once downloaded , just unzip the contents in a folder .Go to the folder where you have unzipped the folder and you can find the following jars in the “lib” folder . ibatis-common-2.jar ibatis-sqlmap-2.jar ibatis-dao-2.jar
Also Read : IBatis vs Hibernate ? Which one to choose?
Introduction to IBatis Tutorial -Part 2

IBatis Tutorial – Sample Application Step 1


Technorati : ibatis