If you encountered this in a log or a search field, it is likely an automated probe by a security scanner or an attacker trying to identify vulnerabilities. CHR - Oracle Help Center
: This is the timeout argument in seconds. If the database takes exactly 5 seconds to respond, it confirms to an attacker that the system is vulnerable to SQL injection. If you encountered this in a log or
: A special dummy table in Oracle used for selecting results from functions that don't belong to a specific table. : A special dummy table in Oracle used
: A SQL comment used to ignore the rest of the original query, preventing syntax errors. : An Oracle subprogram typically used for communication
: This part is intended to break out of a preceding SQL string (like a search filter or input field) by closing a single quote and a parenthesis.
: An Oracle subprogram typically used for communication between database sessions.