This directory containts driver files for the RDB backend to jena.

To be picked up a copy of this directory must be on the java
classpath. In the default jena distribution this is achieved by
copying the etc directory in the jar. If you need to change these
files then you either need to add the changes to the jar or arrange
for them to appear on your classpath ahead of the jar.

There are several types of files in here.

Database.config
    These files define the basic configuration parameters for database
of tpe "Database". These parameters will apply to all layout modes
unless there is an overriding Database_layout.config.
The file format is a standard java properties file. See
Template.config for a template version which includes descriptive comments.

Database_layout.config
    Defines configuration parameters for a specific layout mode for
Database. If this file exists then the corresponding Database.config
will be ignored when this layout is in opertation.
The file format is a standard java properties file.

database_all.sql
   Conventially this is a file of SQL commands referenced by
Database.config but the configuration file is free to pick alternative
naming conventions. 

database_layout.sql
   Conventially this is a file of SQL commands referenced by
Database_layout.config but the configuration file is free to pick
alternative naming conventions.

See doc/rdb/rdb_porting.html for more details on the sql file formats
and how to use these files in porting to a different database or
layout format.


When the database layout changes then the old sql files should be kept
because existing databases will refer to them (the sql file name used
is recorded in the RDF_LAYOUT_INFO table). By convention if we add a
new sql format at jena release X then we the new version of the sql
files will have the name database_layout_X.sql, the new config files
will have the name Database.config and the older version of the config
files will take the name DatabasePreX.config. This enables
applications to create new databases in the old format by using the
database name "DatabasePreX" but by default new databases will use the
new format and old databases will continue working with the old
format.
