Development:XMLDB modifying DML functions

XML database schema > Roadmap > Modifying DML functions

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Note: This article is a work in progress. Please use the page comments or an appropriate moodle.org forum for any recommendations/suggestions for improvement.

Intro/explnation here...

All the work could be performed in one branch, call it MOODLE_17_DML.

Exclusively when Point 1 - Splitting datalib.php was finished.

Details

This is a long process in which a lot of scripts become affected although critical changes are, exclusively in the DML functions. The rest is a repetitive work, changing how such functions are used in hundreds of places and testing them carefully. Documentation of the new final DML library must be ready as soon as possible to allow 3rd part developers to update their contributions.

Following, there is one list of changes to be performed in the DML library with their implications in the rest of the code (note: as the number of changes isn't too much big, move each item to one section!)

1. We need to change all the uses of the LIMIT offset, num clause to use the cross-db compatible SelectLimit() function. Two alternatives seem possible:
   1. Create a new set of get_records_limit() (and get_recordset_limit() ?) functions, allowing to specify the offset, num parameters.
   2. Modify the current get_records() (and get_recordset()) functions to allow two more optional parameters (offset, num)