Configuring Data Sources

UnityJDBC requires information about the data sources being queried in order to validate, optimize, and execute queries against those data sources. All source information is stored in XML files. There are two types of source information files: the sources file and schema files. A sources file with default name sources.xml provides information on all the sources that could be potentially queried. The location of this file is provided via the URL when initializing the driver. Inside the file is information on each source including its connection URL and parameters, JDBC driver, and schema file location. The sample sources file code\test\xspec\UnityDemo.xml is provided in the distribution package. Each data source requires a schema file. The schema file is an XML encoding of the schema information including table and field names, keys, joins, and relation sizes. It is used for validating queries and optimization. Two schema files provided in the distribution are: code\test\xspec\UnityDemoOrder.xml and code\test\xspec\UnityDemoPart.xml.

There are two ways to create your own sources file and associated schema files:

  1. The easiest way is to use the SourceBuilder GUI that can be started using the installed shortcut or running initsources.bat or This GUI will automatically extract source information and build the necessary files. If you are using UnityJDBC as the multisource plugin in SQuirreL SQL, all features of the SourceBuilder are integrated into SQuirreL, and the XML files are generated automatically.

  2. You can manually build a sources file using a text editor. To produce a schema file for a source, open up the program called com/unityjdbc/SourceBuilder/ in the code directory. Modify the JDBC URL, driver path, and output directory accordingly and run the program. The account that you connect with must have read access to the database and associated tables that you want to access. After the XML schema file has been produced, move it to the directory where you want it and update the sources file to reference the correct location. In almost all cases, using the SourceBuilder utility will be faster and easier.