title: What do bit flags in mysqli mean using fetch_field_direct
body: <p>Using mysqli, I can get information about fields like so</p>
  
  <pre><code>$field = mysqli_fetch_field_direct($result, $fieldCount);
  </code></pre>
  
  <p>and I can get the field flags from the result using</p>
  
  <pre><code>$field-&gt;flags
  </code></pre>
  
  <p>The PHP manual says that this returns "An integer representing the bit-flags for the field." but that's all the info I can find. How can I interpret the bit flags? So far, I've worked out that</p>
  
  <p>Integers (length of field doesn't matter) return the following bit flags depending on the attributes specified:</p>
  
  <pre><code>primary key 49967
  primary &amp; unique 53255
  unique key 53251
  foreign key 53257
  unique &amp; index 53259 (Auto increment 49675)
  </code></pre>
  
  <p>Thanks for any help you can offer!</p>