PHP and MySQL basic tutorial (2). Read the PHP and MySQL basic tutorial (2). The data validation clearing space trim function will clear spaces at the beginning and end of the data. Its syntax is: trim ($ first_name); processing of required fields is required for some fields in your database. In this way, fields corresponding to the HTML form cannot be blank. "> <LINKhr data verification
Clear spaces
The trim function will clear spaces at the beginning and end of the data. Its syntax is:
Trim ($ first_name );
Processing of required fields
Some fields must be entered in your database. In this way, the fields corresponding to the HTML form cannot be blank. Of course, this verification process can be handled using the client's JavaScript script, but since we are talking about PHP, we should still use PHP for processing. The following code checks whether the user's last name is entered:
If (ereg (".", $ first_name) = 1)
{
Print ("surname :");
Print ("$ first_name ");
$ Verify = "OK ";
}
Else
{
Print ("<B> error: </B> your surname is not filled ");
$ Verify = "bad ";
}
The ereg pattern recognition function is used to determine whether a specified string contains a substring. Its first parameter is to determine whether it contains a substring. The second parameter specifies the string to be searched, usually a variable. The Ereg function returns "0" (false), indicating that the matching fails, or "1" (true), indicating that the matching is successful. Here, "." is a pattern-type unified character, which represents any character. In this way, the expression ereg (".", $ first_name) = 1 means that the variable $ first_name contains at least one character.
Check the email address
Prepared by: Yangmei compilation clicks in this article: 118
Using the following character constants as the first parameter of the ereg function, you can easily check the e-mail address:
"@": Must contain @
"^ @": @ Cannot be used for header hitting.
"@. *...": A character must exist between @ and.
"... *": It must contain at least two characters after.
"": Spaces are not allowed.
Based on these Parameter examples, you can also design other input verification methods.
Check whether the user name is unique
This action also seems necessary:
Mysql_connect (localhost, username, password );
Mysql_select_db (dbname );
$ Result = mysql_query ("SELECT * FROM tablename
WHERE USER_ID = '$ USER_ID'
");
If ($ row = mysql_fetch_array ($ result ))
{
Print ("<B> error: </B> user name <B> ");
Print ("$ USER_ID ");
Print ("</B> is in use. select another one and try again. ");
Print ("<p> ");
$ Verify = "bad ";
}
Else
{
Print ("User ID :");
Print ("$ USER_ID ");
}
The idea of the code is very simple. I believe it is hard for you to read it here.
Check whether the user name is unique
Prepared by: Yangmei compilation clicks in this article: 118
This action also seems necessary:
Mysql_connect (localhost, username, password );
Mysql_select_db (dbname );
$ Result = mysql_query ("SELECT * FROM tablename
WHERE USER_ID = '$ USER_ID'
");
If ($ row = mysql_fetch_array ($ result ))
{
Print ("<B> error: </B> user name <B> ");
Print ("$ USER_ID ");
Print ("</B> is in use. select another one and try again. ");
Print ("<p> ");
$ Verify = "bad ";
}
Else
{
Print ("User ID :");
Print ("$ USER_ID ");
}
The idea of the code is very simple. I believe it is hard for you to read it here.
