3 database-jdbc(1)

Accessing a Database in Java
How to use JDBC
and
Application Design for O-R Mapping
By Sayed Abdul bari harifal

JDBC Overview
1. Get a Connection to the database.
2. Create a Statement using the Connection.
3. Execute the Statement with SQL string.
4. Use the results.

JDBC Overview
creates Statements
for database actions
selects a specific Connection type
and instantiates it

JDBC Code
/** BAD CODE. We'll fix this later. */
static final String URL = "jdbc:mysql://dbserver/world";
static final String USER = "student";
static final String PASSWORD = "secret";
// 1. Get a Connection to the database.
Connection connection =
DriverManager.getConnection( URL, USER, PASSWORD );
// 2. Create a Statement
Statement statement = connection.createStatement();
// 3. Execute the Statement with SQL command.
ResultSet rs = statement.executeQuery("SELECT * FROM ...");
// 4. Use the Result.
while ( rs.next( ) ) {
String name = rs.getString("name");

Connecting to a Database in Java (1)
 java.sql.Connection is a standard interface for
connecting to any database.
 Each database type requires its own jdbc driver that
implements this interface.
 MySQL driver
mysql-connector-java-5.1.7-bin.jar
 Derby driver: derby.jar or derbyclient.jar
 HSQLDB driver: hsqldb.jar
 DriverManager selects the driver based on URL.

DriverManager returns a Connection
DriverManager
getConnection( url, user,
passwd) : Connection
<<interface>>
Connection
createStatement(): Statement
close( )
isClosed( ): boolean
getCatalog( ): String
MySqlConnection
creates
url = "jdbc:mysql://hostname/database"
HSQLConnection

Patterns Question
DriverManager
getConnection( url, user,
passwd) : Connection
<<interface>>
Connection
createStatement(): Statement
close( )
isClosed( ): boolean
getCatalog( ): String
MySqlConnection
creates
What design pattern is used by DriverManager?
HSQLConnection

Where is the Database Driver?
Driver is in a JAR file.
JAR file must be on the CLASSPATH.
Use one of these:
1. add as an external jar file to your IDE project
2. add the JAR to your CLASSPATH
CLASSPATH = /my/path/mysql-connector.jar;.
3. add JAR using the Java command line:
java -cp /my/path/mysql-connector.jar ...
4. Put JAR file in the JRE/lib/ext directory:
C:/java/jre1.6.0/lib/ext/mysql-connector.jar

Can't find the Driver?
DriverManager finds a registered database driver.
How?
1. Automatically. This should happen with type 4 & 5.
2. Load the driver class in your program:
Class.forName("com.mysql.jdbc.Driver");
3. Add driver to the jdbc.drivers property
System.setProperty("jdbc.drivers",
"com.mysql.jdbc.Driver");
4. Specify jdbc.drivers property on command line:
java -Djdbc.drivers="com.mysql.jdbc.Driver" ...

Database URL
String DB_URL = "jdbc:mysql://dbserver:3306/world";
The format of a database URL is:
Protocol Sub-protocol Hostname Port DatabaseName
Port is the TCP port number where the database server
is listening.
 3306 is the default port for MySQL
Use hostname "localhost" for the local machine.

Database URL
Example: These 4 URL refer to the same database
"jdbc:mysql://localhost:3306/world"
"jdbc:mysql://localhost/world"
"jdbc:mysql:///world"
"jdbc:mysql:/world"
The hostname and port are optional.
For MySQL driver: defaults are localhost and port 3306

JDBC Driver
You can get a JDBC driver (network connector) for most
databases: MySQL, PostgreSQL, Oracle, SQLite ...
5 Types of JDBC drivers
Type 1: JDBC-to-ODBC bridge driver for Microsoft ODBC. Java
JDBC includes the bridge driver: sun.jdbc.odbc.JdbcOdbcDriver.
Type 2: Native-API driver (written in C or C++ using JNI)
Type 3: Pure Java client-to-server driver, use a standard network
protocol. The server translates requests to server-specific protocol.
Type 4: Pure Java drivers implementing a database-specific network
protocol. Java programs can connect directly to the database.
Type 5: The latest.

Exercise: Install JDBC Driver
 Download the mysql-connector-*.jar file
 use http://se.cpe.ku.ac.th/download/mysql
 alternate: http://www.mysql.com
 Install it in your software "library" directory,
e.g. C:/lib/mysql
JDBC Connector for MySQL:
mysql-connector-java-5.x.y.zip

Executing SQL Commands
 To execute an SQL command, use the Connection
object to create an SQL Statement object.
 Statement interface defines methods for executing
commands.
Statement statement =
connection.createStatement( );
// execute an UPDATE command
int count = statement.executeUpdate( "UPDATE City
SET population=30000 WHERE name='Bangsaen'" );
System.out.println(
"Modified " + count + " records");

Executing SQL Queries
 A statement.executeQuery( ) returns a ResultSet.
 ResultSet is a scrollable set of values.
// execute a SELECT command
ResultSet rs = statement.executeQuery(
"SELECT * FROM city WHERE id = "+id );
rs.first(); // scroll to first result
do {
String name = rs.getString(1);// get 1st field
int population = rs.getInt("population");
...
} while( rs.next() );

Search for a City
Scanner console = new Scanner(System.in);
System.out.print( "Name of city to find? " );
String name = console.nextLine().trim();
// This is not safe...
String query =
"SELECT * FROM city WHERE Name='" +name+ "'";
ResultSet rs = statement.executeQuery( query );
Use a statement you already created.

ResultSet Methods
 ResultSet contains one "row" for each result
returned from the query.
 ResultSet contains get methods for column data:
 "get" by column number -- starts at 1 (not 0)!
 "get" by column name -- field names in
table/query.
String query = "SELECT * FROM Country WHERE ...";
// go to first row of results
rs.first( );
// display the values
System.out.println( rs.getString( 1 ) );
System.out.println( rs.getInt( "population" ) );
get by column number
get by name

ResultSet Methods
 A ResultSet contains one "row" for each result
returned from the query. Indices start from 1 (not 0)!
go to next row of results. "false" if no more.
go to previous row. "false" if 1st result.
go to first row of results.
go to last row of results.
go to k-th row of results.
get int value of field "name"
get int value of k-th column in a record
ResultSet
next() : boolean
previous() : boolean
first() : boolean
last() : boolean
absolute( k )
getInt( name: String )
getInt( index: int )
...

Question
What design pattern does ResultSet use?
Hint:
 ResultSet lets you access the results one-by-one
without knowing how the results are organized.
ResultSet rs = statement.executeQuery( "..." );
while ( rs.next( ) ) {
String name = rs.getString("name");
int population = rs.getInt("popuation");
System.out.println( name +" "+population );
}

ResultSet Methods for Getting Data
ResultSet "get" methods return column data:
getLong( 3 ) : get by column index (most efficient)
getLong( "population" ) : get by field name (safest)
getInt( ), getLong( ) - get Integer field value
getFloat( ), getDouble() - get floating pt. value
getString( ) - get Char or Varchar field value
getDate( ) - get Date or Timestamp field value
getBoolean( ) - get a Bit field value
getBytes( ) - get Binary data
getBigDecimal( ) - get Decimal field as BigDecimal
getBlob( ) - get Binary Large Object
getObject( ) - get any field value

ResultSet and Type Compatibility
SQL data types don't exactly match Java data types.
See Java API and JDBC tutorial for conversion rules.
For all compatibilities, see: /tutorial/jdbc/basics/retrieving.html
int pop1 = rs.getInt( "population" );
long pop2 = rs.getLong( "population" );
// float - int conversion is possible, too
float area = rs.getFloat( "surfacearea" );
// convert char(n) to String
String region = rs.getString( "region" );

How to Execute SQL Commands
The Statement interface defines many execute methods:
Resultset rs =
statement.executeQuery("SELECT ...");
 use for statements that return data values (SELECT)
int count =
statement.executeUpdate("UPDATE ...");
 use for INSERT, UPDATE, and DELETE
boolean b =
statement.execute("DROP TABLE test");
 use to execute any SQL statement(s)

Security Problem
Scanner scanner = new Scanner( System.in );
System.out.print( "Name of city to find? ");
String name = scanner.nextLine( );
String query = String.format(
"SELECT * FROM city WHERE name='%s'",
name );

Security Problem (2)
String name = "Bangkok";
"SELECT * FROM city WHERE name='%s'",
name );
Becomes:
query="SELECT * FROM city WHERE name='Bangkok' "

Hack The Code
"SELECT * FROM City WHERE name='%s'"
, name);
"SELECT * FROM City
WHERE name='x' OR 'a'='a'"
Name of City to Find? x' OR 'a'='a

SQL Injection
"SELECT * FROM city WHERE name='%s' ",
name );
Becomes:
"SELECT * FROM city WHERE name='Bangkok' ;
DELETE FROM city WHERE 'x'='x' "
City to find? Bangkok'; DELETE FROM city WHERE 'x'='x

Using a PreparedStatement
PreparedStatement uses placeholders for data values.
PreparedStatement pstmt = connection.prepareStatement(
"SELECT * FROM Country where name = ?" );
// get data for Thailand
pstmt.setString( 1, "Thailand");
ResultSet rs = pstmt.executeQuery( );
saveResultSetAsObject( rs, country1 );
PreparedStatement will
quote the string for you.
Don't use '?'
Substitute "Thailand" for placeholder #1

Reuse a PreparedStatement
You can reuse a PreparedStatement with new data.
// get data for Laos
pstmt.setString( 1, "Laos");
rs = pstmt.executeQuery( );
saveResultSetAsObject( rs, country2 );
Substitute "Laos" for placeholder #1

Create a Class to Manage DB Connection
Create ConnectionManager with a static factory method
ConnectionManager
- connection : Connection
+getConnection( ) : Connection
+close( ) : void
// example how to use
Statement statement =
ConnectionManager.getConnection().createStatement( );

Simple version of manager (1)
public class ConnectionManager {
// literal constants in Java code is baaaad code.
// we will change to a configuration file later.
private static String driver = "com.mysql.jdbc.Driver";
private static String url = "jdbc:mysql://hostname/world";
private static String user = "student";
private static String password = "student";
/* a single shared database connection */
private static Connection connection = null;
private ConnectionManager() { /* no object creation */ }

Simple version of
ConnectionManager (2)
/* the public accessor uses lazy instantiation */
public static Connection getConnection( ) throws ... {
if ( connection == null ) connection = makeConnection();
return connection;
}

Simple version of
private static Connection makeConnection( )
throws SQLException {
try {
Class.forName( driver );
// load the database driver class
connection = DriverManager.getConnection(
url, user, password );
} catch ( FileNotFoundException ex ) {
logger.error("connection error", ex ); // Logging
throw new SQLException( ex );
}
}
/* the public accessor uses lazy instantiation */
public static Connection getConnection( ) throws ... {
if ( connection == null ) connection = makeConnection();
return connection;
}

Simple version of
public class DataAccessException extends RuntimeException
{
public DataAccessException(String arg) {
super(arg);
}
}
Catch, Log, and rethrow any exception.
 Necessary to avoid Exceptions in app.
 Translate low-level exception into higher layer exception
What is a DataAccessException?
 translate checked exceptions into unchecked exception to simplify
code.

ConnectionManager using Properties
private static Connection makeConnection( ) throws ... {
Properties props = PropertyManager.getProperties( );
String url = props.getProperty("jdbc.url");
// load the database driver class
connection = DriverManager.getConnection(url, props);
}
• Give All the properties to DriverManager.
• DriverManager uses jdbc.drivers to locate the JDBC Driver
class!
• No "ClassNotFoundException"

ConnectionManager Using Properties
// literal constants in Java code is baaad.
// we will change to a configuration file later.
private static String url = "jdbc:mysql://hostname/world";
private static String user = "student";
private static String password = "student";
DELETE THIS

How to do Object Persistence
Choices for How to do Object Persistence?
1. write your own DAO using JDBC
2. Use an Object-Relational Mapping (ORM) Framework
 Hibernate, TopLink, MyBatis, Apache Cayenne
1. Use a Standard Persistence API.
 Java Persistence Architecture (JPA)

standard used in JavaEE

implemented by EclipseLink, Hibernate, OpenJPA
 Java Data Objects (JD)

implemented by DataNucleus.org
 "standard" means you can change the
implementation without changing your code

The World Application
 Insert class diagram or ER diagram

CityDao for World Application
CityDao
find( id: Integer ): City
findByName( name: String ): City[*]
find( query: String ) : City[*]
save( Country ) : boolean
delete( Country ) : boolean
 The primary key is an integer city ID.
 Search by name is used in our application, so I add a method
for it.

CityDao using JDBC (1)
public class CityDao {
private static final Logger logger = ...; // log4J
private static final CountryDao countryDao;
private static HashMap<Integer,City> cache = ...;
/** retrieve a city by its id */
public City findById( Integer id ) {
if ( cache.containsKey(id) ) return cache.get(id);
List<City> list = find("WHERE id = "+id);
return list.get(0);
}
/** retrieve a city by name */
public List<City> findByName( String name ) {
name = sanitize( name );
List<City> list = find("WHERE name = '"+name+"'");
return list;
}

/** find cities using a general query, use a
* WHERE ..., HAVING ..., or other selection clause */
public List<City> find( String query ) {
List<City> list = new ArrayList<City>( );
Statement stmt = ConnectionManager
.getConnection( ).createStatement();
String sqlquery = "SELECT * FROM city c " + query;
try {
logger.debug("executing query: " + sqlquery );
ResultSet rs = stmt .executeQuery( sqlquery );
while ( rs.next() ) {
City c = resultSetToCity( rs );
list.add( c );
}
} catch ( SQLException sqle ) {
logger.error( "error executing: "+sqlquery, sqle);
} finally {
if (stmt!=null) try { stmt.close(); }
catch(SQLException e) { /* forget it */ }
return list;

/** convert a ResultSet entry to a City object */
private City resultSetToCity(ResultSet rs)
throws SQLException {
City city = null;
Integer id = rs.getInt("id");
// is this city already in cache? if so, use it
if ( cache.contains(id) ) city = cache.get(id);
else city = new City();
city.setId(id);
city.setName( rs.getString("Name") );
city.setDistrict( rs.getString("District") );
city.setPopulation( rs.getInt("Population") );
String countrycode = rs.getString("countrycode");

// add this city to the cache
if ( ! cache.containsKey(id) ) cache.put(id, city);
// now get reference to the country this city refers
logger.info("get country for city "+city.getName() );
Country country = countryDao.findById( countrycode );
city.setCountry( country );
return city;
}

Why CityDao Needs a Cache
What if the application requests cityDao.find("Bangkok")
two times?
 We should return the same object each time.
 Necessary to avoid infinite loops:
1. cityDao uses JDBC and gets data for Bangkok
2. the countrycode for Bangkok is "THA". cityDao must
convert this to a country object reference.
3. cityDao calls countryDao.findById( "THA" )
4. countryDao finds Thailand, and the capital city has a cityID =
3320. It must convert this to a city reference.
5. countryDao calls cityDao.findById( 3320 )
6. cityDao uses JDBC and gets data for Bangkok again

CityDao: delete
public boolean delete( City city ) {
if ( city == null || city.getId() == null ) return false;
Long id = city.getId( );
Statement statement = ConnectionManager.getStatement( );
int count = 0;
if ( statement == null ) return false;
String query = "DELETE FROM city WHERE id=" + id;
try {
count = statement.executeUpdate( query );
logger.error( "error executing: "+query, sqle );
} finally {
ConnectionManager.closeStatement( statement );
}
// is city in the cache?
if ( cache.containsKey(id) ) cache.remove( id );
return count > 0;
}

CityDao: save and update
public boolean save( City city ) {
Long id = city.getId( );
if ( id == null ) this is a new city, save it ;
else {
if ( cache.containsKey( id ) )
this city is already in database, update it
else
this city is not in the database, save it
but check that no other city has this id
}
We can use save( ) for both saving a new object and updating an
existing object.

UI
/** prompt for a city name and display city info */
private void citySearch( ) {
out.print("Input name of city: ");
String name = in.next().trim();
// run the query
City city = cityDao.findByName( name );
if ( city == null ) {
out.println("Sorry, no match or query error");
}
else {
out.println("Name: "+city.getName( ) );
out.println("District: "+city.getDistrict( ) );
out.println("Country: "
+city.getCountry( ).getName( ) );
...
}
}

UI search for country
private void countrySearch() {
out.print("Input name of country: ");
String name = in.next().trim();
// perform the query
List<Country> results = countyDao.findByName( name );
if ( results == null ) ... // failed
for( Country country : results ) {
out.printf("Name: %sn", country.getName() );
out.printf("Capital: %sn", country.getCapital() );
out.printf("Region: %sn", country.getRegion() );

Exercise
 Finish the CityDao and CountryDao.
 Write JUnit tests to verify they are correct.
 What happens if you enter invalid country name?

Use a Configuration File
Purpose:
 Configuration data such as database URL, username,
password, should be in a file not in the Java code.
 Put this data in a configuration file.
Example: world.config
# World database properties
jdbc.url=jdbc:mysql://localhost/world
user=student
password=secret
jdbc.drivers=com.mysql.jdbc.Driver

Loading Properties
The java.util.Properties class can read or write
"properties" files in this format. (can also write XML).
// get name of the configuration file
String config = "world.config";
// allow user to change this: java -dworld.config=...
config = System.getProperty("world.config", config );
// load the properties
Properties properties = new Properties( );
try {
FileInputStream fis = new FileInputStream( config );
properties.load( fis );
fis.close( );
} catch ( FileNotFoundException e ) { ... }

Use Properties in
ConnectionManager
private void makeConnection( ) {
Properties properties =
PropertyManager.getProperties();
String jdbc_driver =
properties.getProperty("jdbc.drivers");
String url = properties.getProperty("jdbc.url");
// pass all remaining properties to DriverManager
// including user and password properties
try {
class.forName( jdbc_driver );
connection =
DriverManager.getConnection(url,properties);
log exception and rethrow as DataAccessException
} catch ( FileNotFoundException e ) {
...

Properties Filename is a property, too
Use a System property to get configuration file name.
// get name of the configuration file
String configfile = System.getProperty( "world.config" );
if ( configfile == null )
configfile = DEFAULT_CONFIG_FILE;
C> java -Dworld.config=c:/temp/config.txt world.jar
This enables user to change the filename at runtime:

java.util.Properties (a HashTable)
Properties p = new Properties( )
create new java.util.Properties object
String value = p.getProperty( name )
get a named property; returns null if not found.
String value =
p.getProperty( name, default_value )
get a property, returns default_value if not found.

System Properties
String value = System.getProperty( name )
get a system property
Properties p = System.getProperties( )
get all the system properties

Details of Statement and
ResultSet

Understanding statement objects
 A Statement object is tied to a Connection.
 Use an re-use a statement object for many
database commands.
 If the Connection is closed, the statement object
is invalid (disconnected).
 Statement object consumes resources
 close it when you are finished
statement.executeQuery( "SELECT * FROM ... " );
...
statement.close( );

Understanding ResultSet
 ResultSet is tied to a statement and a database
connection.
 if statement or connection is closed, results are
gone
 if another command is executed, results are gone
 ResultSet can change (!) after performing the query
 ResultSet can update a database
Statement stmt = connection.createStatement(
ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE );

Using ResultSet to update a database
 Specify ResultSet.CONCUR_UPDATABLE when
creating Statement.
 Requires (a) support by database driver, (b) UPDATE
privilege on tables
// rs is scrollable, will not show changes made
// by others, and will be updatable
Statement statement = connection.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE );
rs.next();
int population = rs.getInt("population");
// add 10,000 to the population
rs.updateInt( "population", population+10000 );
rs.updateRow( );

RowSet
RowSet is like ResultSet, but...
 data not tied to database
connection.
 can be cached.
 can be updated by re-
connecting to database
 can store other kinds of data,
such as from file or
spreadsheet
<<interface>>
ResultSet
<<interface>>
RowSet
<<interface>>
CachedRowSet
<<interface>>
WebRowSet

RowSet Question
Suppose part of your application
is expecting a ResultSet, but
you change the lower layers to
return a RowSet instead.
 Do the upper layers of the
application need to change?
<<interface>>
ResultSet
<<interface>>
RowSet
<<interface>>
CachedRowSet
<<interface>>
WebRowSet

JTable
 Swing object looks like a spreadsheet table.
A JTable

JTable Class Diagram
 JTable displays data returned by a TableModel.
JTable TableModel
describes data in the
table
AbstractTableModel
getColumnCount( ) : int
getColumnName( index ) : String
getColumnClass( index ) : Class
getRowCount( ) : int
getValueAt( row, col ) : Object

Design a TableModel for Queries
 Design a TableModel to manage a ResultSet
JTable ResultSetTableModel
ResultSetTableModel(statement)
runQuery( query : String )
AbstractTableModel
getColumnCount( ) : int
getColumnName( index ) : String
getColumnClass( index ) : Class
getRowCount( ) : int
getValueAt( row, col ) : Object

Implementing TableModel
 ResultSet contains some of the data we need.
class ResultSetTableModel {
private Statement statement;
private ResultSet rs;
public Object getValueAt(int row, int col) {
if ( rs == null ) return null;
rs.absolute( row + 1 );
rs.getObject( col );
}
public int getRowCount() {
if ( rs == null ) return 0;
rs.last(); // move to last row
rowCount = rs.getRow();
return rowCount;
}

Implementing TableModel (2)
 ResultSet is missing some information.
public int getColumnCount( ) {
}
public String getColumnName( int col ) {
}

ResultSet Meta-data
 ResultSet has a getMetaData( ) method that
returns a ResultSetMetaData object.
 ResultSetMetaData describes the ResultSet.
try {
ResultSet resultSet =
statement.executeQuery( query );
ResultSetMetaData metadata = resultSet.getMetaData();
int numberOfColumns = metadata.getColumnCount();
for(int col=1; col<=numberOfColumns; col++) {
// get name and SQL datatype for each column
String name = metadata.getColumnName( col );
int type = metadata.getColumnType( col );
int typeName = metadata.getColumnTypeName( col );
} catch( SQLException sqle ) { ... }

Closing the Connection
 It is advisable to close Connection object when done.
This frees resources and ensures data integrity.
Connection connection = DriverManager.getConnection(...);
/* use the database */
...
/* done using database */
public void close( ) {
if ( connection == null ) return;
try {
connection.close();
}
catch ( SQLException sqle ) { /* ignore it */ }
finally { connection = null; }
}

Connection Sharing
 A database connection consumes resources.
 All instances can share the same Connection object.
 To enforce this use the Singleton Pattern:
 use a factory method to get connection
 the method always returns the same instance of
the connection

Let the IDE build your Country Class
public class Country {
private String name;
private String continent;
private String region;
private float surfaceArea;
private long population;
private float lifeExpectancy;
private long gnp;
private String governmentForm;
private String capital;
/** auto-generated constructor
public Country(String name,...
{
this.name = name;
this.continent = continent;
Eclipse: Source menu

Summary
 JDBC specifies standard interfaces for communicating with
different databases.
 To use JDBC you need a JDBC or ODBC driver for the
database.
 The application must load a database-specific driver.
DriverManager will choose driver when creating a Connection.
 a Connection object manages the connection to a database.
 a Statement object is used to submit database statements and
get results.
 A query returns a ResultSet containing data and meta-data.
 A ResultSet can be read-only or updateable depending on the
Statement object (specified in Statement constructor).
 properly close a Statement or Connection when finished to
release resources and ensure data integrity.

Important Design Concepts
 JDBC specifies standard interfaces for databases.
Any database can use JDBC by writing classes that
implement these interfaces.
 To re-use a connection in different classes, use the
Singleton Pattern and a Factory Method for getting
the connection object.
 Use a finally clause on try - catch blocks to ensure
that some code is always executed.
Inside the try - catch, you must not use 'return' since
this would bypass the "finally" clause. Use 'break'.

Learning More
 Sun Java Tutorial: JDBC Database Access
 Java API for the java.sql package:
 DriverManager
 Connection
 Statement
 ResultSet
 ResultSetMetaData
 DatabaseMetaData (describes the database)

Resources
MySQL
 http://dev.mysql.com/
Learning SQL
 http://www.w3schools.com/sql/
nice tutorial and command reference
Learning JDBC
 JDBC Trail in Sun's Java Tutorial.
 Dietel, Java How To Program, Chapter 25.
 ... and zillions of resources on the web

Resources
SQL Explorer for Eclipse
 http://www.sqlexplorer.org
 Eclipse Update: http://eclipsesql.sourceforge.net/
 Standalone app:
http://sourceforge.net/projects/eclipsesql
 http://www.onjava.com/pub/a/onjava/2005/05/11/sqle
xplorer.html
Eclipse Data Tools Platform (Eclipse Project)
http://www.eclipse.org/datatools

Resources
 Netbeans database tutorials
http://netbeans.org/kb/docs/ide/mysql.html
http://netbeans.org/kb/docs/web/mysql-webapp.html

3 database-jdbc(1)

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