After many previous attempts and false starts, Drupal 6's entire core database schema is now documented and cross referenced. You can view the documentation using the contributed Schema module; see the attached screenshot for a demonstration (click to enlarge). Thanks to webchick, add1sun, pwolanin, JirkaRybka, Moshe, chx, yched, and others for contributing their knowledge of the dusty corners of the schema.
If you are a module author, when you port a module to Drupal 6 and create your hook_schema() function, you should also document the schema. Doing so is easy: just add 'description' fields to each table and field in the schema structure. For example:
<?php
function mymodule_schema() {
$schema['mytable'] = array(
'description' => t('Stores whiz-bang cool data for nodes provided by the MyModule module.'),
'fields' => array(
'nid' => array(
'type' => 'int',
'not null' => TRUE,
'description' => t('The {node}.nid that this row is for.'),
),
// etc.
return $schema;
}
?>
Placing a table reference within a description inside of curly-braces causes the reference to be displayed as a hyperlink to that table's documentation on the Schema Describe page.
