Was recently working with a mainframe code for an update operation and my code was sending "NULL" for the last name. Surprisingly there was a person with NULL a

Was recently working with a mainframe code for an update operation and my code was sending "NULL" for the last name. Surprisingly there was a person with NULL as last name (seems it's a valid last name, search facebook or LinkedIn and you will find tons of them), had to pull my hair when I saw that all the update transactions are being applied with that particular person's account. TLDR: Careful, there could be some one with last name or first name = NULL"