RE: [PHP] How to prevent duplicated values?
Hello I think using UNIQUE is the way to go simply because of data integrety (= how do you spell this??? ; ) ) If you don't use UNIQUE and you are not write locking your table you might accidently get duplicate Values. UNIQUE is the only way to prevent duplicate data without a lot of hassle. This doesn't mean you cannot check upon duplicates first, which I think is obsolete since you need to add error checking code anyway. Regards Stefan Langer
RE: [PHP] How to prevent duplicated values?
What I would do would instead be to put an index on that column, then with a simple select check if that username is free or not. Based on what I get in return I can then either insert the data or return the form to the visitor with information about it. Much more simple in the long run. I don't see how this method is simpler than querying the table to see if user name exists then returning true or false. Either way you are inserting the data or returning and error to be displayed on the form. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] How to prevent duplicated values?
Radwan Aladdin wrote: Hello.. I want to prevent mySQL from storing the same value in a specified field (Username).. so how can I do it? Regards.. Make it field UNIQUE. Best Bao -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] How to prevent duplicated values?
Run a select first to check whether you have that value stored and by using an if statement add the new value or show an error. - Original Message - From: BAO RuiXian [EMAIL PROTECTED] To: Radwan Aladdin [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Monday, January 26, 2004 11:35 AM Subject: Re: [PHP] How to prevent duplicated values? Radwan Aladdin wrote: Hello.. I want to prevent mySQL from storing the same value in a specified field (Username).. so how can I do it? Regards.. Make it field UNIQUE. Best Bao -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] How to prevent duplicated values?
BAO RuiXian wrote: Radwan Aladdin wrote: I want to prevent mySQL from storing the same value in a specified field (Username).. so how can I do it? Make it field UNIQUE. That's the easy method, but usually not very smart. It only causes MySQL to generate an error which you then have to take care of in your application. Much better to have an index on the Username column and then use a select to check if the name exist. If it doesn't it is OK to insert. Much easier to handle in PHP. Personally I avoid using such things as UNIQUE or NOT_NULL (unless the column have a default value) on columns, just because it is more complex to handle the MySQL errors than write your own code to check it in PHP. /T -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] How to prevent duplicated values?
Radwan Aladdin wrote: But I'm using VB OCX file to show the result... I tried the UNIQUE and it worked greate! So do you mean I should use other ways? If it works, then great. The problem, as I can see it, is if you have a form where a user applies for a user account (I assume that since the column name is Username) and you then query MySQL to add the data to the table. If that user name already exist, MySQL will give an error saying that it can't insert since there is already a row with that name. You will have to handle this and then tell the new user that the name he wants already is taken. What I would do would instead be to put an index on that column, then with a simple select check if that username is free or not. Based on what I get in return I can then either insert the data or return the form to the visitor with information about it. Much more simple in the long run. Also this will put you in charge of fault handling and not the database. Remember that PHP just send/receive data to/from MySQL. It can't interpret error messages MySQL outputs. Therefore I prefer to check things like this myself. It is pretty easy to write global functions that then can be used in many places for this instead of handling the error messages from MySQL. /T -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] How to prevent duplicated values?
Thomas Svenson wrote: BAO RuiXian wrote: Make it field UNIQUE. That's the easy method, but usually not very smart. It only causes MySQL to Well, if there is an easy method, why we bother to use a more complicacted way? generate an error which you then have to take care of in your application. We need to take care of various errors any way whenever we are dealing with databases. Much better to have an index on the Username column and then use a select to check if the name exist. If it doesn't it is OK to insert. Much easier to handle in PHP. Quite to the opposite, if the database can handle it, why bother to write one's own with something adding more burden to the database (select statement), more process on the php code (check each item of the select result) and possibly less error-proof in your php checking code? Personally I avoid using such things as UNIQUE or NOT_NULL (unless the column have a default value) on columns, just because it is more complex to handle the MySQL errors than write your own code to check it in PHP. Can't get it. If there is a existing method, why not use it. The home-brew one is always low in aspects. I don't understand why you think checking errors is complext, which has to be done in all your codes, even a trivial one. /T Best Bao -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
