Why is my table not automatically created at the time of custom module install?
The following line is not correct.

'primary_key' =&gt; array('id'),


Replace 'primary_key' with 'primary key'.

In Drupal 7 you do not need to call drupal_install_schema() nor drupal_uninstall_schema() for the database tables your module uses.

You can just declare the functions.

function drupalform_install() {}

function drupalform_uninstall() {}


Just update the code, uninstall the module, and re-install it.