drupal_write_record in drupal-6.x/includes/common.inc

Save a record to the database based upon the schema.

forum_form_submit in drupal-6.x/modules/forum/forum.admin.inc

Process forum form and container form submissions.

node_type_form_submit in drupal-6.x/modules/node/content_types.inc

Implementation of hook_form_submit().

node_type_save in drupal-6.x/modules/node/node.module

Saves a node type to the database.

taxonomy_form_term_submit in drupal-6.x/modules/taxonomy/taxonomy.admin.inc

Submit handler to insert or update a term.

... See full list