OwncloudContactsOfficial/appinfo/migrate.php

<?php
namespace OCA\Contacts;

class MigrationProvider extends OC_Migration_Provider{

	// Create the xml for the user supplied
	function export( ) {
		$options = array(
			'table'=>'contacts_addressbooks',
			'matchcol'=>'userid',
			'matchval'=>$this->uid,
			'idcol'=>'id'
		);
		$ids = $this->content->copyRows( $options );

		$options = array(
			'table'=>'contacts_cards',
			'matchcol'=>'addressbookid',
			'matchval'=>$ids
		);

		// Export tags
		$ids2 = $this->content->copyRows( $options );

		// If both returned some ids then they worked
		return (is_array($ids) && is_array($ids2));

	}

	// Import function for contacts
	function import() {
		switch($this->appinfo->version) {
			default:
				// All versions of the app have had the same db structure, so all can use the same import function
				$query = $this->content->prepare('SELECT * FROM `contacts_addressbooks` WHERE `userid` = ?');
				$results = $query->execute(array($this->olduid));
				$idmap = array();
				while($row = $results->fetchRow()) {
					// Import each addressbook
					$addressbookquery = OCP\DB::prepare('INSERT INTO `*PREFIX*contacts_addressbooks` '
						. '(`userid`, `displayname`, `uri`, `description`, `ctag`) VALUES (?, ?, ?, ?, ?)');
					$addressbookquery->execute(
						array(
							$this->uid,
							$row['displayname'],
							$row['uri'],
							$row['description'],
							$row['ctag']
						)
					);
					// Map the id
					$idmap[$row['id']] = OCP\DB::insertid('*PREFIX*contacts_addressbooks');
					// Make the addressbook active
					OCA\Contacts\Addressbook::setActive($idmap[$row['id']], true);
				}
				// Now tags
				foreach($idmap as $oldid => $newid) {

					$query = $this->content->prepare('SELECT * FROM `contacts_cards` WHERE `addressbookid` = ?');
					$results = $query->execute(array($oldid));
					while($row = $results->fetchRow()) {
						// Import the contacts
						$contactquery = OCP\DB::prepare('INSERT INTO `*PREFIX*contacts_cards` '
							. '(`addressbookid`, `fullname`, `carddata`, `uri`, `lastmodified`) VALUES (?, ?, ?, ?, ?)');
						$contactquery->execute(
							array(
								$newid,
								$row['fullname'],
								$row['carddata'],
								$row['uri'],
								$row['lastmodified']
							)
						);
					}
				}
				// All done!
			break;
		}

		return true;
	}

}

// Load the provider
new MigrationProvider('contacts');