<?php
/*
create_relation.php
Create this file into your root directory of vtiger i.e. vtigercrm/
and then run this file directly using your browser 
for example localhost/vtigercrm/create_relation.php
*/
include_once('vtlib/Vtiger/Module.php');
require_once('vtlib/Vtiger/Block.php');
require_once('vtlib/Vtiger/Field.php');

$moduleInstance = Vtiger_Module::getInstance('Events');
$block = Vtiger_Block::getInstance('LBL_DESCRIPTION_INFORMATION',$moduleInstance);

$field3 = new Vtiger_Field();
$field3->name = 'sample_id';
$field3->label = 'Echantillon';
$field3->table = 'vtiger_activity';//$moduleInstance->basetable;
$field3->column = 'sample_id';
$field3->columntype = 'VARCHAR(100)';
$field3->uitype = 10;
$field3->typeofdata = 'V~O';
$block->addField($field3);

$field3->setRelatedModules(Array('Products'));
$block->save($moduleInstance);

echo "done";
?>