Development:Using XMLDB
From MoodleDocs
(This docs is in progress of writing and editing, aimed to help third-party module developer to switch to XMLDB)
Developing module using XMLDB
Everywhere in Moodle now use XMLDB. Developed to prevent from creating custom database schemas for different database system. In every module, there is "db/" directory where database structure stored.
Convert MySQL syntax to XMLDB
This can be done easily by using XMLDB Editor built in every Moodle. Simply go to Administration >> Miscellaneous >> XMLDB Editor