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~ Query Tool

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While working at the Vooruit Arts Centre I got the assignment to create a tool to query an Oracle database with ticketing data. There were a few requirements for the Query Tool, in the current version all of these are met:

By publishing the Query Tool on my website I hope that the fruits of my labour can be enjoyed by a wider audience. To see it in action you can give it a spin. A recent version, version 6, of the JRE is needed.

How Do I Use The Query Tool?

The program supports two ways to query a database:

The two buttons below are self explanatory. When the button “CVS Export” is hit a CVS file is created in a configured directory.

Depending on the complexity of a query it can take a long time before results are returned. Because the application is multithreaded the user interface remains responsive and the query can be stopped at any time.

The contents of the tab “log” gives you an idea what the application does. When something goes awry while executing a query a message appears in this tab.

The tab “Config” can be used to set configuration parameters. The tab “Help” contains… helpful information.


How Do I Add My Own Queries?

The list of predefined queries is constructed by iterating over SQL-files in a configured directory. Adding additional queries to the program is easy, just add an extra SQL-file to the directory. An SQL-file should have the following format, otherwise it is ignored:

SQL-INSTRUCTION with zero or more !{PARAMETERS}!

In the screen shot above this query is visible:

Select products in category
Select all the products in a category.
products WHERE categoryid = !{category}!  

To make the queries dynamic the Query Tool supports different kinds of parameters. A parameter has this form: !{type name}!, the name is optional. If there is a name specified it is used as a label in the interface, otherwise type is used. There are three types of parameters:

  1. Parameters that define a type. For each type a corresponding user interface is rendered. E.g. for the type string a text field is rendered. The supported types are:
    • !{string}!
    • !{boolean}!
    • !{double}!
    • !{date}!
    • !{integer}!
  2. Parameters for raw SQL. A textfield is rendered, the contents is directly injected in the SQL-query. It has this format: !{sql}!
  3. Parameters for lists. In the example above a list parameter is used. These lists are fetched from the database. E.g. a list of categories. The SQL-instruction and name of the list parameters can be configured.

If you want to use your own database you need to configure the database connection string. The program uses JDBC to connect to the database. It uses metadata provided by the JDBC layer. If your database has a JDBC driver with support for metadata the Query Tool will work correctly. The JDBC driver must be included in the classpath.


The Query Tool uses the famfamfam mini icons.

For demoing purposes the executable contains a lightweight hsql database. The data in the database is a modified version of the Microsoft Northwind database. The northwind hsql database is created with this SQL-script.