title: Does deleting data from a database affect the cursor storing the data?
body: <p>I have to move some files from database A to database B.</p>
  
  <p>So, I query the data into cursor from database A, then delete the data in the database A.</p>
  
  <p>After that, I use cursor to insert the the data rows to database B. Are there any problems in this procedure?</p>
  
  <p>Because someone told me that cursor may be only a reference, not really store the data in the cursor object. So, if I delete the database A before I insert the data into database B, there may have something abnormal!</p>
  
  <p>Is there anyone who knows whether cursor is a reference to database or it really saves the data in the object?</p>