无法找到PHP为MySQL错误号定义

Question

In my HTML code there's a select with options and a button that opens a dialog to allow the user to add to the options list [via DB/PHP/jQuery].

In the case where they enter an option that already exists in the DB, I want to catch the MySQL Duplicate Key error and use it to trigger code that finds the Option that matches what the User entered, and selects it for them.

mysqli::$errno returns 1062 , and my code works great when I use the raw number.

But what if that number changes in some future update? I would rather use a define provided by the PHP installation.

The PHP Manuel hints at such a define:

Client error message numbers are listed in the MySQL errmsg.h header file, server error message numbers are listed in mysqld_error.h. In the MySQL source distribution you can find a complete list of error messages and error numbers in the file Docs/mysqld_error.txt.

I found the 'mysqld_error.txt' document which has the following define:

#define ER_DUP_ENTRY 1062

There is also the following document: http://dev.mysql.com/doc/refman/5.6/en/error-messages-server.html which has the same define.

But, when I try using this in my PHP code I get a " Use of undefined constant ER_DUP_ENTRY - assumed 'ER_DUP_ENTRY' " notice. I even tried mysqli::ER_DUP_ENTRY .

Anyone knows a way to do this without using the numeric value?

Answer 1

All I had to do was to enclose the constant name in quotes. In my case it works perfectly.

if ('ER_DUP_ENTRY') {
    #logic here;
}