PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

114 Chapter 4 String Manipulation and Regular Expressions
Table 4.2 String Case Functions and Their Effects
Function Description Use Value
ucwords() Capitalizes first ucwords($subject) Feedback From
character of each
Web Site
word in the string
that begins with
an alphabetic
character
Formatting Strings for Storage: addslashes() and
stripslashes()
In addition to using string functions to reformat a string visually, you can use some of
these functions to reformat strings for storage in a database. Although we don’t cover
actually writing to the database until Part II,“Using MySQL,” we cover formatting
strings for database storage now.
Certain characters are perfectly valid as part of a string but can cause problems, particularly
when you are inserting data into a database because the database could interpret
these characters as control characters.The problematic ones are quotation marks (single
and double), backslashes (\), and the NULL character.
You need to find a way of marking or escaping these characters so that databases such
as MySQL can understand that you meant a literal special character rather than a control
sequence.To escape these characters, add a backslash in front of them. For example, “
(double quotation mark) becomes \” (backslash double quotation mark), and \ (backslash)
becomes \\ (backslash backslash). (This rule applies universally to special characters,
so if you have \\ in your string, you need to replace it with \\\\.)
PHP provides two functions specifically designed for escaping characters. Before you
write any strings into a database, you should reformat them with addslashes(), as
follows if your PHP configuration does not already have this functionality turned on by
default:
$feedback = addslashes(trim($_POST['feedback']));
Like many of the other string functions, addslashes() takes a string as a parameter and
returns the reformatted string.
Figure 4.3 shows the actual effects of using these functions on the string.
You may try these functions on your server and get a result that looks more like
Figure 4.4.