Chapter 2. Installation

Index:

1. System Requirements
2. Setting the CLASSPATH
3. Loading the Driver
4. Connecting to the Database

System Requirements

HXTT Paradox packages include a Type 4 JDBC driver. Type 4 indicates that the driver is written in Pure Java, and communicates in the database system's own network protocol. Because of this, the driver is platform independent; once compiled, the driver can be used on any system. HXTT Paradox can run on any platforms with Java VM, which includes Microsoft Windows, Novell Netware, OS2, UNIX, and LINUX. HXTT Paradox supports Personal Java, JDK1.0.X, JDK1.1.X, JDK1.2.X, JDK1.3.X, JDK1.4.X and JDK1.5.X. HXTT Paradox includes a database engine which can support multi-user access. It supports { UNION | INTERSECT | EXCEPT | MINUS } [ ALL ] query , INNER JOIN, FULL JOIN, LEFT JOIN, RIGHT JOIN, NATURAL JOIN, CROSS JOIN, and subquery which includes single-row subquery, multirow subquery, multiple-column subquery, inline views, and correlated subquery.

Setting the CLASSPATH

When java loads any class, it searches a list known as the classpath. This is a list of directories where classes are placed, or a list of jar files (archives containing classes and other resources) or both. HXTT Paradox driver is a Type 4 driver. You can do this in many different methods, but the most command are:

1. Setting the CLASSPATH environment variable.
2. putting it on the command line using the -cp parameter.
3. placing it in the JVM/s lib/ext directory.
4. extract all files in jar file into the directory of your application.

You can know detailed information about "Setting the Classpath" from your JDK Tools and Utilities. Let's use JDBC3.0 package as a simple sample. To put Paradox_JDBC30.jar into your class path, you should use "export CLASSPATH=/usr/share/lib/Paradox_JDBC30.jar:$CLASSPATH" on Solaris and Linux, and "SET CLASSPATH=\javalib\Paradox_JDBC30.jar;%classpath%" on Windows.

Loading the Driver

Any source that uses JDBC needs to import the java.sql package by using " import java.sql.*;".

HXTT Paradox driver' name is com.hxtt.sql.paradox.ParadoxDriver, and you can uses it without involving hard coding the driver into your code. You do this by setting the jdbc.drivers system property. For example, for command line apps you can use:
java -Djdbc.drivers=com.hxtt.sql.paradox.ParadoxDriver yourApp
Then, the JVM upon startup will load the drivers automatically. Some applications (JBoss, Tomcat etc) support a .properties file which they use to save putting this on the command line.

The second method is the most common and involves you loading the driver yourself. It's simple:
Class.forName("com.hxtt.sql.paradox.ParadoxDriver");
From then on you can get connections from DriverManager.
Note: If Class.forName() throws ClassNotFoundException, you should check your classpath.

Connecting to the Database

After the driver has been registered with the DriverManager, you can obtain a Connection instance that is connected to a particular database by calling DriverManager.getConnection(). With JDBC, a database is represented by a URL (Uniform Resource Locator).

        Embedded:
                jdbc:Paradox:[//]/[DatabasePath][?prop1=value1[&prop2=value2]] (You can omit that "//" characters sometimes)
                        For example:
                                "jdbc:Paradox:/."
                                "jdbc:Paradox:/c:/data" for Windows driver
                                "jdbc:Paradox:///c:/data" for Windows driver
                                "jdbc:Paradox:////usr/data" for unix or linux
                                "jdbc:Paradox://///192.168.10.2/sharedir" for UNC path
                                "jdbc:Paradox:/./data"
        Remote Access:
                jdbc:Paradox://host:port/[DatabasePath]
                        For example: "jdbc:Paradox://domain.com:3099/c:/data" if one ParadoxServer is run on the 3099 port of domain.com

To connect, you need to get a Connection instance from JDBC. To do this, you use the DriverManager.getConnection() method:

Connection con = DriverManager.getConnection(url, properties);

There are a few different signatures for the getConnection() method. You should see the API documentation that comes with your JDK for more specific information on how to use them. You can specify additional properties to the JDBC driver by placing them in a java.util.Properties instance and passing that instance to the DriverManager when you connect.

When your code then tries to open a Connection, and you get a No driver available SQLException being thrown, this is probably caused by the driver not being in the class path, or the JDBC url not being correct.

To close the database connection, simply call the close() method to the Connection:

con.close();