Connecting to a MySQL Database

This document demonstrates how to set up a connection to a MySQL database 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, 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.

Note: This document uses the NetBeans IDE 6.0 Release. If you are using NetBeans IDE 6.1, see Connecting to a MySQL Database. If you are using NetBeans IDE 6.5, see Connecting to a MySQL Database.

Contents

To follow this tutorial, you need the following software and resources.

Notes:

Connecting to the MySQL RDBMS

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 (). 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:

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. In the Database URL field, replace the default <HOST>:<PORT>/<DB> with a forward-slash (/) so that the entry now reads: jdbc:mysql:///. For User Name and Password, enter root and nbuser, respectively. Optionally, select the Remember password option. 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:

You are now connected to the MySQL RDBMS in the IDE. Note that the new connection node icon appears whole () when you are connected to a database. Likewise, it appears broken () 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:

Right-click the connection node you just added and choose Execute Command. The SQL Editor opens in the main window. 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:

Connecting to the Database Instance

You can now connect to the MyNewDatabase database instance that you just created from within the IDE. To do so, follow the same procedure used above when connecting to the MySQL RDBMS:

In the Services window (Ctrl-5) choose Connect Using from the right-click menu of the MySQL driver. The New Database Connection dialog opens. 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. For User Name and Password, enter root and nbuser respectively:

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. This is covered in the follow-up tutorial Creating a Simple Web Application using a MySQL Database.

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:

Using the SQL Editor

In the Database Explorer, expand the MyNewDatabase connection node () 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. 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.

To execute the query, either click the Run SQL () 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:

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 () 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 ():

Using the Create Table Dialog

In the Database Explorer, right-click the Tables node and choose Create Table. The Create Table dialog opens. In the Table Name text field, type Subject. 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. For Column Name, enter id. For Data Type, choose SMALLINT from the drop-down list, then click the Add Column button. 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 0

[checked] name VARCHAR 50

[checked] description VARCHAR 500

[checked] FK_counselorID SMALLINT 0

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

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 () 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:

Choose Execute Command from the Tables folder in the Database Explorer. A blank canvas opens in the SQL Editor in the main window. 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')

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. 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:

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:

To run the SQL script on MyNewDatabase:

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. Make sure your connection to MyNewDatabase is selected from the Connection drop-down box in the toolbar at the top of the Editor:

Click the Run SQL () 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. 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. 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.

See Also

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: