When quoting strings, one of the annoying tasks is switching the single quotes to double quotes:
To work with the string “It’s the dog’s toy” requires turning the single quotes into double:
‘It”s the dog”s toy’.
In 10g Oracle introduced Q-Quote delimiters:
For literals where doubling the quotes is inconvenient or hard to read, you can designate an escape character using the notation q’esc_char … esc_char’
Some examples from the docs:
q'(name LIKE '%DBMS_%%')'
q'<'Data,' he said, 'Make it so.'>'
q'"name like '['"'