Connecting to a MySQL Database

Contributed and maintained by Troy Giunipero
November 2007

This document demonstrates how to configure the MySQL database server on your computer and set up a connection to it from NetBeans IDE. Once connected, you can begin working with MySQL in the IDE's Database Explorer by creating new databases and tables, populating tables with data, and running SQL queries on database structures and content. This tutorial is designed for beginners with a basic understanding of database management and application development, who want to apply their knowledge to working with MySQL in NetBeans IDE.

MySQL is a popular Open Source relational database management system (RDBMS) commonly used in web applications due to its speed, flexibility and reliability. MySQL employs SQL, or Structured Query Language, for accessing and processing data contained in databases.

In order to work through this tutorial, you need to have the following software installed on your computer:

  1. NetBeans IDE 6.0
  2. Java SE Development Kit (JDK™) version 5.0 or higher*
  3. MySQL server (download)

*Note: You need to install the Java SE Development Kit (JDK™) in order to install and run NetBeans IDE. The JDK includes the Java Runtime Environment (JRE), as well as various tools and API's necessary for development in Java.

Expected duration: 25 minutes

Content on this page applies to NetBeans IDE 6.0

The following topics are covered below:

Installing and Configuring MySQL

If you already have the MySQL database set up and running on your computer, skip ahead to Registering the Database in NetBeans IDE. By way of example, this tutorial demonstrates how to install the MySQL Community Server on both Windows XP and Unix-based systems.

Unix

  1. Run sudo apt-get install mysql-server in a terminal window. MySQL is automatically downloaded and installed.
  2. Start the MySQL server by running sudo /etc/init.d/mysql start.
  3. Run mysqladmin -u root password nbuser. This allows you to set a new password for the root user, which is initially blank. For purposes of this tutorial, use nbuser.

Windows XP

  1. Run the self-extracting file. The MySQL Setup Wizard opens to guide you through the installation process. Accept all default settings.
  2. Upon completing installation, allow the MySQL wizard to immediately configure the server by making sure the Configure the MySQL Server Now checkbox is selected. This will allow an instance of the server to be created, which will run as a Windows service on your computer.
  3. In the MySQL Server Instance Configuration wizard, select Standard Configuration. Click Next. When you arrive at the step allowing you to set Windows options, select the Include Bin Directory in Windows PATH checkbox. This will later allow you to perform a simple check to make sure the MySQL service is up and running:

    Include Bin Directory in Windows PATH checkbox selected in the Configuration wizard
  4. For purposes of this tutorial, set the root password to: nbuser. Finally, click Execute to allow the wizard to generate the server instance on your computer. If you encounter any problems, refer to the MySQL Reference Manual included in your installation or the online documentation.

Before continuing further, it is important to understand the components found in MySQL's root directory:

Connecting to MySQL from NetBeans IDE

Connections to databases are managed using database drivers, which enable applications written in different programming languages to interact with the database management system. NetBeans IDE 6.0 comes bundled with the MySQL Connector/J driver, which is a pure Java implementation of the JDBC API, and communicates directly with the MySQL server using the MySQL protocol.

Begin by examining the functionality offered by the Database Explorer located in the IDE's Services window (Ctrl-5). The Database Explorer is represented by the Databases node (database node icon). From this interface you can connect to database servers, view current connections, add database drivers, as well as create, browse or edit database structures.

Now that you have the MySQL database server installed and configured, you can connect to it from the NetBeans IDE using the Database Explorer. Note that you are connecting to the database server. In the next step, you will create a database instance through this connection. Do the following:

  1. In the Database Explorer, expand the Drivers node, then right-click the MySQL (Connector/J driver) and choose Connect Using. The New Database Connection dialog displays.
  2. In the Database URL field, replace the default <HOST>:<PORT>/<DB> with a forward-slash (/) so that the entry now reads: jdbc:mysql:///.
  3. For User Name and Password, enter root and nbuser, respectively. Optionally, select the Remember password option.
  4. Click OK, then click OK again to accept the default schema and exit the dialog. A new Connection node displays in the Database Explorer under the Databases node:

    new connection node displayed in database explorer

You are now connected to MyNewDatabase in the IDE. Note that the new connection node icon appears whole (connection node icon) when you are connected to a database. Likewise, it appears broken (broken connection node icon) when there is no connection.

At later stages, when working with databases through the Database Explorer, you may need to manually connect to a database. You can do so by right-clicking the broken database connection node and choosing Connect.

Creating a Database Instance

A common way of interacting with databases is through an SQL editor. NetBeans IDE has a built-in SQL Editor for this purpose. The SQL Editor is generally accessible via the Execute Command option from the right-click menu of the connection node (or of the connection node's child nodes). Now that you are connected to the MySQL server, you can create a new database instance using the SQL Editor. For purposes of this tutorial, create an instance called MyNewDatabase:

  1. Right-click the connection node you just added and choose Execute Command. The SQL Editor opens in the main window.
  2. In the SQL Editor, type:
    create database MyNewDatabase;
    Then, right-click anywhere within the SQL Editor and choose Run Statement. The SQL query executes against the database. In the Output window (Ctrl-4) you will see output similar to the following, indicating that the query executed successfully:

    Output window displaying output from executed query

Connecting to the Database Instance

  1. In the Services window (Ctrl-5) choose Connect Using from the right-click menu of the MySQL driver. The New Database Connection dialog opens.
  2. In the Basic Setting tab, enter the Database's URL in the corresponding text field. The URL is used to identify the type and location of a database server. In this example, you need to specify the host name (i.e. the location of the server), the port number on which the database communicates, and the name of the database instance being used. In this case you can enter: jdbc:mysql://localhost:3306/MyNewDatabase.
  3. For User Name and Password, enter root and nbuser respectively:

    New Database Connection dialog containing connection details
  4. Click OK, then click OK again to exit the dialog. A new Connection node displays in the Database Explorer under the Databases node, just as it did when you connected to the MySQL server.

Note: While you can now access MyNewDatabase through your connection in the IDE, you have not yet made it available to any specific application. At this stage, you can use the IDE to access and modify the database, but cannot do so within the context of an application yet.

Creating Database Tables

Now that you have connected to MyNewDatabase, you can begin exploring how to create tables, populate them with data, and modify data maintained in tables. This allows you to take a closer look at the functionality offered by the Database Explorer, as well as NetBeans IDE's support for SQL files.

MyNewDatabase is currently empty. In the IDE it is possible to add a database table by either using the Create Table dialog, or by inputting an SQL query and running it directly from the SQL Editor. Here you can explore both methods:

  1. Using the SQL Editor
  2. Using the Create Table Dialog

Using the SQL Editor

  1. In the Database Explorer, expand the MyNewDatabase connection node (connection node icon) and note that there are three subfolders: Tables, Views and Procedures. Right-click the Tables node beneath the MyNewDatabase connection node and choose Execute Command. A blank canvas opens in the SQL Editor in the main window.
  2. In the SQL Editor, type in the following query. This is a table definition for the Counselor table you are about to create:
    CREATE TABLE Counselor (
        id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT,
        firstName VARCHAR (50),
        nickName VARCHAR (50),
        lastName VARCHAR (50),
        telephone VARCHAR (25),
        email VARCHAR (50),
        memberSince DATE DEFAULT '0000-00-00',
        PRIMARY KEY (id)
    );                      
                        
    Note: Queries formed in the SQL Editor are parsed in Structured Query Language (SQL). SQL adheres to strict syntax rules which you should be familiar with when working in the IDE's Editor. Upon running a query, feedback from the SQL engine is generated in the Output window indicating whether execution was successful or not.

  3. To execute the query, either click the Run SQL (run SQL button) button in the task bar at the top (Ctrl-Shift-E), or right-click within the SQL Editor and choose Run Statement. The IDE generates the Counselor table in the database, and you receive a message similar to the following in the Output window:

    Output window indicates successful execution
  4. To verify changes, right-click the Tables node in the Database Explorer and choose Refresh. The Refresh option updates the Database Explorer's UI component to the current status of the specified database. Note that the new Counselor table node (table node icon) now displays under Tables in the Database explorer. If you expand the table node you can see the columns (fields) you created, starting with the primary key (primary key node icon):

    Counselor table displayed in Database Explorer

Using the Create Table Dialog

  1. In the Database Explorer, right-click the Tables node and choose Create Table. The Create Table dialog opens.
  2. In the Table Name text field, type Subject.
  3. In the first row displayed, select the Key check box. You are specifying the primary key for your table. All tables found in relational databases must contain a primary key. Note that when you select the Key check box, the Index and Unique check boxes are also automatically selected and the Null check box is deselected. This is because primary keys are used to identify a unique row in the database, and by default form the table index. Because all rows need to be identified, primary keys cannot contain a Null value.
  4. For Column Name, enter id. For Data Type, choose SMALLINT from the drop-down list, then click the Add Column button.
  5. Repeat this procedure by specifying all remaining fields, as shown in the table below:

    Key Index Null Unique Column Name Data Type Size
    [checked] [checked] [checked] id SMALLINT 3
    [checked] name VARCHAR 50
    [checked] description VARCHAR 500
    [checked] FK_counselorID SMALLINT 3

    You are creating a table named Subject that will hold data for each of the following records:

    • Name: name of the subject
    • Description: description of the subject
    • Counselor ID: counselor ID that corresponds to an ID from the Counselor table

    Create Table dialog with selected fields for Subject table

    Make sure that the fields in your Create Table dialog match those shown above, then click OK. The IDE generates the Subject table in the database, and you can see a new Subject table node (table node icon) immediately display under Tables in the Database Explorer.

Working with Table Data

In order to work with table data, you can make use of the SQL Editor in NetBeans IDE. By running SQL queries on a database, you can add, modify and delete data maintained in database structures. To add a new record (row) to the Counselor table, do the following:

  1. Choose Execute Command from the Tables folder in the Database Explorer. A blank canvas opens in the SQL Editor in the main window.
  2. In the SQL Editor, type in the following query:
    INSERT INTO Counselor
        VALUES (1, 'Ricky', '"The Dragon"', 'Steamboat','334 612-5678', 'r_steamboat@ifpwafcad.com', '1996-01-01')
  3. To execute the query, right-click within the SQL Editor and choose Run Statement. In the Output window, you can see a message indicating that the query was successfully executed.
  4. To verify that the new record has been added to the Counselor table, in the Database Explorer, right-click the Counselor table node and choose View Data. A new SQL Editor pane opens in the main window. When you choose View Data, a query to select all the data from the table is automatically generated in the upper region of the SQL Editor. The results of the statement are displayed in a table view in the lower region. In this example, the Counselor table displays. Note that a new row has been added with the data you just supplied from the SQL query:

    new record added to Counselor table

Running an SQL Script

Another way to manage table data in NetBeans IDE is by running an external SQL script directly in the IDE. If you have created an SQL script elsewhere, you can simply open it in NetBeans IDE and run it in the SQL Editor.

For demonstrative purposes, download ifpwafcad.sql and save it to a location on your computer. This script creates two tables similar to what you just created above (Counselor and Subject), and immediately populates them with data.

Because the script overwrites these tables if they already exist, delete the Counselor and Subject tables now so it becomes obvious that new tables are being created when the script is run. To delete tables:

  1. Right-click the selected table node in the Database Explorer and choose Delete.
  2. In the Confirm Object Deletion dialog that displays, click Yes. Note that the table node is automatically removed from the Database Explorer.

To run the SQL script on MyNewDatabase:

  1. Choose File > Open File from the IDE's main menu. In the file browser navigate to the location where you previously saved ifpwafcad.sql and click Open. The script automatically opens in the SQL Editor.
  2. Make sure your connection to MyNewDatabase is selected from the Connection drop-down box in the toolbar at the top of the Editor:

    Connection drop-down box in the SQL Editor toolbar
  3. Click the Run SQL (run SQL button) button in the SQL Editor's task bar. The script is executed against the selected database, and any feedback is generated in the Output window.
  4. To verify changes, right-click the MyNewDatabase connection node in the Runtime window and choose Refresh. The Refresh option updates the Database Explorer's UI component to the current status of the specified database. Note that the two new tables from the SQL script now display as a table nodes under MyNewDatabase in the Database Explorer.
  5. Choose View Data from the right-click menu of a selected table node to see the data contained in the new tables. In this manner, you can compare the tabular data with the data contained in the SQL script to see that they match.
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Next Steps

This concludes the Connecting to a MySQL Database tutorial. This document demonstrated how to configure MySQL on your computer and set up a connection to the database server from NetBeans IDE. It also described how to work with MySQL in the IDE's Database Explorer by creating new database instances and tables, populating tables with data, and running SQL queries.

For related and more advanced tutorials, see the following resources:


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