title: odbc_exec vs odbc_excute
body: <p>from php manual:</p>
  <blockquote>
  <p><strong>odbc_exec</strong> — Prepare and execute an SQL statement</p>
  <p><strong>odbc_execute</strong> — Execute a prepared statement</p>
  </blockquote>
  <p>which is prepared by <strong>odbc_prepare</strong></p>
  <p>so what is the different? why not to use <strong>odbc_exec</strong> directly?</p>