Existence checking or existence detection is an important aspect of many computer programs. An existence check before reading a file can catch and/or prevent a fatal error, for instance. For that reason, most programming language libraries contain a means of checking whether a file exists.
An existence check can sometimes involve a "brute force" approach of checking all records for a given identifier, as in this Microsoft Excel Visual Basic for Applications code for detecting whether a worksheet exists:
References
Existence detection Wikipedia(Text) CC BY-SA