title: deleting all records for all tables in memory in Kdb+
body: <p>I would like to delete all records for all tables in memory but still keep the schemas.</p>
  <p>for example:</p>
  <pre><code>a:([]a:1 2;b:2 4);
  b:([]c:2 3;d:3 5);
  </code></pre>
  <p>I wrote a function:</p>
  <pre><code>{[t] t::select from t where i = -1} each tables[]
  </code></pre>
  <p>this didnt work, so i tried</p>
  <pre><code>{[t] ![`t;enlist(=;`i;-1);0b;()]} each tables[]
  </code></pre>
  <p>didnt work either.
  Any idea or better ways?</p>