Customize PHP function to output XML

Finish writing a PHP function to fetch records from database and write the results as XML to a file on disk. There are over 30,000 rows of data in our production environment, so data needs to be retrieved from the database in smaller datasets and saved incrementally to an XML file so as to not overload server memory. For example, instead of fetching all rows at once you would fetch 1000 rows at a time, save those rows to a file, and iterate until all rows have been saved to the file. There is currently a PHP function, SaveAsXML(), that does this operation, but is limited to retrieving only a fixed set of results. This function needs to be modified to allow it to retrieve and save all records by iterating through the database.