Database types and config files

The system-table feature of Advanced Query Tool reads the system tables (dictionary / catalog) for the database. These system tables differ greatly; they are:

• different for different database types (Oracle / DB2),
• different for database implementations (DB2/UDB for AIX is different from DB2 for z/OS), and
• even different between releases of a database.

To provide a simple and customizable way of reading the system tables, the SQL statements for all system-table queries are held in config files. No SQL statements are hard-coded in the AQT code. The config files also give the structure for the Database Explorer, plus the various list-boxes and menus used for navigating through the system objects. Designing Advanced Query Tool in this way has given it tremendous flexibility:

• if you want, you can amend these config files to add in your own system queries, or change the existing ones
• you can distribute different config files to different categories of users
• support for new database types can be implemented by building and distributing a new config file.

If you wish to amend any of the config files you should see Customizing your System.

The use of config files however provides an element of complexity as follows: when AQT connects to a database it needs to work out which config file to use. The discussion below describes how this works within AQT. You may need to know this if you are making changes to the config files, or if you are having problems with the system.

Database Type

AQT operates on the principal of auto-detecting the database type (Oracle, SQL Server, etc). When AQT connects to a database it issues the GetInfo ODBC API call to get the database type. AQT is reliant on the database returning sensible information to this call and the type being known to AQT (see the next section).

If you wish to know what name is being returned here, see Help > Database Details > Database Type or Options > Config Files.

Config File

Having found the database type, AQT then needs to determine which config file to use for this database. AQT uses a cross-reference between database type and the config file name. This cross-reference can be seen in Options > Config Files. These entries are initially populated when AQT is run for the first time, however you can amend them if you are adding a new database type or if your database identifies itself by a name different to what AQT expects.

Options > Config Files describes how these entries work.

Future releases of AQT will add extra entries to this list, as support for other databases is included.

Config File Directory

The directory where the config files are held is give by Options > File Locations > Location of Config Files. By default this is app-path\cfg where app-path is the directory where the AQT executable resides. If your config files are held elsewhere you will have to change this.

Options > File Locations has more information on this setting.