Connect to MySQL database

hectorrodriguez

Beginner

Posts: 1

Date of registration: Jan 27th 2009

1

Tuesday, January 27th 2009, 4:41am

How do I connect to a MySql database?
Hector Rodriguez

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Manuel

Administrator

Posts: 256

Date of registration: Jul 16th 2008

Location: Erlangen, Germany

Occupation: Software Developer

Hobbies: Jabaco, game theory, text-mining

2

Tuesday, January 27th 2009, 9:55pm

The recommended way from the MySQL-website is connecting to the MySQL-Server through JDBC with the Connector/J-driver. MySQL Connector/J is a native Java driver that converts JDBC (Java Database Connectivity) calls into the network protocol used by the MySQL database.

The installation of this driver is very simple: Download the driver and copy the included Jar-file (e.g. "mysql-connector-java-3.0.17-ga-bin.jar") to the "[...]\jre\lib\ext"-folder in your current Java-installation.

The JDBC API is designed to make it possible for you to write a single Jabaco/Java program and to use it to manipulate the data in a variety of different SQL database servers without a requirement to modify and/or recompile the program.

Connection-sample:

Jabaco Source

On Error Resume Next
   Dim driver As Class 
   driver = Class.forName("com.mysql.jdbc.Driver")
   If driver = Nothing Then MsgBox "Not found!"
   On Error Goto 0
   Call Database1.Connect("jdbc:mysql://server:port/database", "username", "password")

You have to modify server, port, database, username and password. Short usage-sample:

	Jabaco Source
1 2 3 4 5	Dim myRes As ResultSet myRes = Database1.ExecuteStatement("SELECT * FROM users LIMIT 10") Call myRes.first MsgBox myRes.getString(1) MsgBox myRes.getString("nickname")

Further information about JDBC: http://java.sun.com/products/jdbc/overview.html
Further information about MySQL with JDBC: http://dev.mysql.com/usingmysql/java/

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Charlie

Beginner

Posts: 1

Date of registration: May 31st 2009

3

Sunday, May 31st 2009, 9:30pm

Sorry but something is not clear...

I put a command button on a form and I wrote this:

Source code

Private Sub Form_load

On Error Resume Next
   Dim driver As Class 
   driver = Class.forName("com.mysql.jdbc.Driver")
   If driver = Nothing Then MsgBox "Not found!"
   On Error Goto 0
   Call Database1.Connect("jdbc:mysql://localhost/database", "username", "password")

End Sub

Public Sub Command1_Click()

Dim myRes  As ResultSet
   myRes = Database1.ExecuteStatement("SELECT * FROM dati LIMIT 100")
   Call myRes.first 
   MsgBox myRes.getString(1)
   MsgBox myRes.getString("Nome")

End Sub

but running it nothing appened.
I mean that the compiling is OK but the field of database is not showed.

These are the messages wrote after clicking the button:

Source code

Listening for transport dt_shmem at address: Jabaco77248
Exception in thread "AWT-EventQueue-1" java.lang.NullPointerException
	at VB.DataBase.ExecuteStatement(DataBase.jsrc:35)
	at Form1.Command1_Click(Form1.jsrc:15)
	at Form1$CommandButton._Click(Form1.jsrc:20)
	at VB.CommandButton.actionPerformed(CommandButton.jsrc:98)
	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
	at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
	at java.awt.Component.processMouseEvent(Unknown Source)
	at javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.awt.Component.processEvent(Unknown Source)
	at java.awt.Container.processEvent(Unknown Source)
	at java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at VBA.JabacoEventQueque.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)

Whats my mistake?

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Fabricio Nicolau

Beginner

Posts: 1

Date of registration: Jun 13th 2011

Location: Vila Velha - ES - Brasil

Occupation: Consultor

Hobbies: Programação

4

Monday, June 13th 2011, 4:53pm

I had this problem.
What i do?

Source code

	Java.sql.SQLException: Before start of result set	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)	at com.mysql.jdbc.ResultSetImpl.checkRowPos(ResultSetImpl.java:841)	at com.mysql.jdbc.ResultSetImpl.getStringInternal(ResultSetImpl.java:5650)	at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5570)	at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5610)	at MDIChild1.cmd1_Click(MDIChild1.jsrc:5)	at MDIChild1$CommandButton._Click(MDIChild1.jsrc:10)	at VB.CommandButton.actionPerformed(CommandButton.jsrc)	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)	at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)	at java.awt.Component.processMouseEvent(Unknown Source)	at javax.swing.JComponent.processMouseEvent(Unknown Source)	at java.awt.Component.processEvent(Unknown Source)	at java.awt.Container.processEvent(Unknown Source)	at java.awt.Component.dispatchEventImpl(Unknown Source)	at java.awt.Container.dispatchEventImpl(Unknown Source)	at java.awt.Component.dispatchEvent(Unknown Source)	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)	at java.awt.Container.dispatchEventImpl(Unknown Source)	at java.awt.Window.dispatchEventImpl(Unknown Source)	at java.awt.Component.dispatchEvent(Unknown Source)	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)	at java.awt.EventQueue.access$000(Unknown Source)	at java.awt.EventQueue$1.run(Unknown Source)	at java.awt.EventQueue$1.run(Unknown Source)	at java.security.AccessController.doPrivileged(Native Method)	at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)	at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)	at java.awt.EventQueue$2.run(Unknown Source)	at java.awt.EventQueue$2.run(Unknown Source)	at java.security.AccessController.doPrivileged(Native Method)	at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)	at java.awt.EventQueue.dispatchEvent(Unknown Source)	at VBA.JabacoEventQueque.dispatchEvent(JabacoEventQueque.java:20)	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)	at java.awt.EventDispatchThread.run(Unknown Source)

This post has been edited 1 times, last edit by "Fabricio Nicolau" (Jun 13th 2011, 4:59pm)

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