A string constant is defined as the sequence of characters that are bounded by single quotes i.e., (‘). It can be used during insertion or while passing the characters to the database objects. This is an important feature when performing the parsing of data. In the case of PostgreSQL, string constant is allowed with single quotes but embedded by a C-style backslash.
Example: ‘This is an example of a string constant bound by single quotes.’
Intermediate PostgreSQL Interview Questions and Answers