Kodo does require an existing database against which to operate. However, Kodo ships with a small, open-source, pure-java database called Hypersonic that can be used for development without requiring an existing database installation.

Kodo has built-in support for all the major databases, including Oracle, Microsoft SQL Server, Sybase, and Informix. In addition, Kodo provides APIs that allow the developer to adapt Kodo to work with any other database that provides a JDBC-compiant driver. A full list of the supported databases can be found at Appendix B, Supported Databases.

Kodo requires Java Development Kit version 1.2.2 or higher. Additionally, if you will be accessing a database other than Hypersonic, Kodo requires a JDBC driver that can communicate with your database. All other libraries needed by Kodo are provided in the Kodo distribution. A list of all the libraries that Kodo requires and uses can be found at Appendix F, Development and Runtime Libraries.

JDBC drivers are typically obtained from the database vendor's web site. In addition, there are many third-party companies that provide JDBC drivers for various databases. For a comprehensive list of existing JDBC drivers, see the Sun JDBC driver database at: http://servlet.java.sun.com/products/jdbc/drivers.

SolarMetric does not usually endorse any specific JDBC driver for a particluar database. Provided the driver is truly JDBC compliant, it should work with Kodo without problems. Typically it is a good idea to first look at the JDBC driver that your database vendor provides, since these are often high-quality and free. An advantage of the transparent JDO API is that you can simply "drop in" a different JDBC driver version and change a few properties, and you can test your application without changing any code. This makes the process of profiling your application's performance with different JDBC drivers a very simple task.

Kodo utilizes version 2.0 of the JDBC specification, and requires that a driver be JDBC 2.0 compliant. In addition, Kodo uses the JDBC 2 Standard Extensions, which are provided in the Kodo distribution.

Certainly. Kodo provides a very flexible set of mapping options to be able to integrate your Java object model with almost any relational database schema. In addition, Kodo provides extensible APIs that allow the developer to create their own mappings for those non-standard relational constructs that may not be included with Kodo "out of the box". Furthermore, Kodo provides a reverse mapping tool, which allows developers to automatically generate a Java object model from an existing schema, which dramatically reduces the amount of time the developer needs to spend manually setting up the mappings. To get started with the reverse mapping tool, see Chapter 3, Reverse Mapping Tool Tutorial.

Yes. Kodo allows you to design your application in a object-centric fashion, and can automatically generate a consistent relational schema from your object model. This is ideal for developers who are designing a new application that does not need to integrate with an existing schema. See Section 7.1, “Mapping Tool”.

Probably. Kodo's mapping capabilities are quite flexible, and the Kodo mapping tools provide facilities to deal with this "meet-in-the-middle" scenario. See Section 7.1.1, “Using the Mapping Tool” for a more detailed description.

Yes. Kodo can operate simultaneously against an arbitrary number of databases at the same time. Utilizing XA transactions, you can even ensure transactional consistency across a hetergeneous set of databases when using container managed transactions.

There is no limit to the size of table against Kodo can operate, nor is there any limit to the number of tables in the database. Kodo is used in applications that use databases ranging from just a few tables, to databases that have thousands of tables with millions or rows.