cannot make table through .install file into database

i am new to drupal and trying to make table into drupal database. i have written create query in .install file and the book i am referring says that when we try to run drupal it will create table in drupal database automatically. can some one help me how can we do the database connection.....

My code is this.

<?php
// $Id$
function annotate_install()
{
drupal_set_message(t('Begin installion of anotate module.'));

switch ($GLOBALS['db_type'])
{
case 'mysql':
case 'mysqli':

db_query("CREATE TABLE annotations (
uid int NOT NULL default 0,
nid int NOT NULL default 0,
note longtext NOT NULL,
timestamp int NOT NULL default 0,
PRIMARY KEY (uid, nid)
);"
);

$success =TRUE;
break;

case 'pgsql':
db_query("CREATE TABLE annotations (
uid int NOT NULL default 0,
nid int NOT NULL default 0,
note longtext NOT NULL,
timestamp int NOT NULL default 0,
PRIMARY KEY (uid, nid)
);"
);
$success =TRUE;
break;

default:
drupal_set_message(t('Unsupported Database.'));
echo '1';
}
if ($success)
{
drupal_set_message(t('The module table installed successfully'));
echo '2';
}
else
{
drupal_set_message(t('Installation of annotation module was Unsuccessful'),'error');
echo '3';
}
}

does drupal create table automatically of we need to write some connection query in .module file for it.