Importance of link identifier in mysql_real_escape_string ()

Question

Why is it necessary to use the link identifier as input when using mysql_real_escape_string (). I know that this function should be used with MySQL queries, but the function actually just manipulates the string.

Answer 1

From the PHP manual :

Resets special characters in unescaped_string, taking into account the current character set of the connection so that it can be placed in mysql_query (). If binary data must be inserted, this function must be used.

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Answer 2

http://ilia.ws/archives/103-mysql_real_escape_string-versus-Prepared-Statements.html

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Answer 3

mysql_real_escape_string:

Resets special characters in unescaped_string, taking into account the current character set of the connection so that it can be placed in mysql_query ().