It is almost safe, but not entirely, since another user could slip in a row with your number in the split second between your Select ... and your Insert. That is the case for blocking the Select ... Insert sequence as one logical unit of work so the target table is locked from Select through Insert.
PB ----- ----- Original Message ----- From: John Griffin To: Steve Marquez ; MySQL List Cc: PHP eMail List Sent: Friday, June 06, 2003 2:51 PM Subject: RE: Duplicate records Hello Steve, Do a select on the record before you insert it. If the record does not exist in the database (i.e. mysql_num_rows () == 0) than it is safe to do the insert. John -----Original Message----- From: Steve Marquez [mailto:[EMAIL PROTECTED] Sent: Friday, June 06, 2003 3:41 PM To: MySQL List Cc: PHP eMail List Subject: Duplicate records Hello. I am adding a record to a MySQL Database using PHP. I have the records listed by the field: $id_num. I want the DB to be updated only with new id numbers, and return an error if there is a duplicate number already in the DB. Here is the code I am using: <?php $insert_data = "INSERT into articles Values ( '<a href=\"upload_form.php?id_num=$id_num\">edit</a>', '<a href=\"delete.php?id_num=$id_num\">delete</a>', '$id_num', '$title', '$author', '$article_contents', '$start_date', '' );"; $response = mysql_query( $insert_data, $dbh ); $get_table_data = "SELECT * FROM ccfs"; $response = mysql_query( $get_table_data, $dbh ); ?> Can anyone help me? Hope this makes sense. Thanks! Steve Marquez Marquez Design [EMAIL PROTECTED] www.marquez-design.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
