title: creating table in mysql database with codeigniter
body: <p>I try to create a table with codeigniter in mysql DB with following code:</p>
  
  <pre><code>$posts_fields=array(
          'id'=&gt;array('type' =&gt; 'INT','constraint' =&gt; 5,'unsigned' =&gt; TRUE),
          'title'=&gt;array('type' =&gt;'VARCHAR','constraint' =&gt; 100),
          'content'=&gt;array('type'=&gt;'text'),
          'create_time'=&gt;array('type'=&gt;'INT','constraint'=&gt;12));
  
      $this-&gt;dbforge-&gt;add_field($posts_fields);
      $this-&gt;dbforge-&gt;create_table('posts');
  </code></pre>
  
  <p>but anytime get error "NO DATABASE SELECTED".</p>
  
  <p>how can I select a database to create tables in it??
  (this database is not default database)</p>