title: why mysql row_count is always -1 after update?
body: <p>I execute an update statement which affects 1 row. Then I write select row_count() and the result is always -1. </p>
  
  <p>I checked out <a href="http://dev.mysql.com/doc/refman/5.5/en//information-functions.html#function_row-count" rel="nofollow">row_count</a> in mysql but I dont understand what I have to config in my mysql to make row_count() on. </p>
  
  <p>Anybody can help me?</p>
  
  <p>Also the same thing when I use insert like this.</p>
  
  <p>INSERT INTO tb_fr_itemsderendicionfondorotatorio (VERSION,estado,ejercicio,importe,tema,oidObjeto,tipoObjeto,codigoObjeto,oid_Ren‌​dicionFondoRotatorio,oid_AnulacionRendicionFondoRotatorio,fecha) VALUES (0,1,0,3000,'mt',18679,'AnticipoRendicion','2013000005',4979,NULL,'2013-05-25'); </p>
  
  <p>SELECT ROW_COUNT(); </p>
  
  <p>I m making test from SQLYog interface and always return -1. In server Im using hibernate with java.</p>