Save Database values in textfield on page load

Things Todo

Build the form with textfield and value of textfield set with prepopulated data.

sample form with textfield, Anytime we load form we will have name textfield set to value(if exist).
After submit new value will be set in textfield.

function MODULENAME_basicinfo_form() {
  $form = array();
  //Assumption : your query return proper result.
  $artcheckin=1;
  $result=db_query("SELECT name FROM users WHERE   users.uid=:uid",array(':uid'=>$artcheckin))->fetchField();

  $form['name'] = array(
    '#type' => 'textfield',
    '#title' => t('Name'),
    '#description' => t('Please enter your name.'),
    '#size'=>12,
    '#default_value' => $result,);

  $form['submit'] = array (
    '#type' => 'submit',
    '#value' => 'Submit',
  );
  return $form;
}

function MODULENAME_basicinfo_form_submit($form, &$form_state) {
//Not required.
/*$artcheckin=1;
$result=db_query("SELECT name FROM users WHERE users.uid=:uid",array(':uid'=>$artcheckin))->fetchField();
$form['name']['#default_value'] = $result;*/


//Update the name with new value in DB.


drupal_set_message('hello--'. $form_state['values']['name']);

There are also diff ways just retaining the form elements value. But above mention solution is best as per my understanding.

I am able to do the first step and will be able to do the third step as well ..How do i pass the object to form definition and then populate the values of the form when the page is loaded

It depends on where you are calling the form, but here is an example:

function my_module_menu()
{
  $menu['my_form_page/%'] = array
  (
    'title' => 'My Form',
    'page callback' => 'my_form_page',
    'page arguments' => array(1),
    'access callback' => TRUE,
  );
  return $menu;
}

function my_module_load_data($item_id)
{
  return db_query('SELECT value1 FROM {some_table} WHERE item_id = :item_id', array(':item_id' => $item_id))->fetchObject();
}

function my_form_page($item_id)
{
  $my_object = my_module_load_data($item_id);
  return drupal_get_form('my_form', $my_object);
}

function my_form($form, &$form_state, $my_object)
{
  $form['element1'] = array
  (
    '#type' => 'textfield',
    '#title' => t('Item 1'),
    '#default_value' => $my_object->value1,
  );
  return $form;
}

As you can see, my drupal_get_form() is called from a menu callback function. Before it is called, I load the data, and then pass that loaded data to the form definition. In the form definition, I use the data to populate the form element.