PHP-and-MySQL/C4/User-Registration-Part-6/English-timed
From Script | Spoken-Tutorial
| Time | Narration |
| 00:00 | Hello everyone, welcome to this Spoken Tutorial which is more of an update tutorial and not a full length video. |
| 00:08 | Some one has pointed out to me that in my register script, I need some kind of check to note if the user has been registered or not by the "username" that they specify. |
| 00:19 | Let us go back to our form which is here. Here you can type your 'full name'. You can choose a 'username' and a 'password'. |
| 00:28 | I have had these values here before. Let us get rid of them for now. |
| 00:33 | But, what we want is, when we are choosing the username... |
| 00:37 | for example, let's say I'm registering with the username "alex". In the database we can see here that the username "alex" already exists. |
| 00:47 | So, what we will do is check the existence of the username. |
| 00:50 | If the username already exists, we are not going to let the user register because we don't want a double username. |
| 01:01 | If I were to register here, let me put the password in and choose the username as "alex". The username "alex" is already in the database. |
| 01:13 | Let's change this for namesake and click Register. |
| 01:20 | I have been successfully registered. |
| 01:23 | Let us look inside our database. We can see that we have two usernames with "alex". |
| 01:28 | Now this causes problems while logging in. |
| 01:31 | The 1st occurrence of name, this one here will be logged in and this one will be ignored. |
| 01:39 | So, this person really will never be able to login into the database. |
| 01:44 | So, let's just delete this. |
| 01:48 | You need to create some kind of check to see if the 'username' already exists. |
| 01:53 | This is incredibly easy. There are more than one method for doing it. |
| 01:59 | But I am going for the simplest and probably the most effective way which is going to work. |
| 02:05 | The first thing I want to do is, take my code to connect to my database. |
| 02:12 | Selecting my database, I want to take this up to just where the 'submit' button is checked. |
| 02:20 | So, this is just connecting to the database. I am inside here. |
| 02:26 | Then, under here I can start my code to check my 'username'. |
| 02:31 | Now, you can't put your check anywhere. For simplicity, I am just going to put it here and kill the rest of the script. |
| 02:39 | If the 'username' has been found, I can put it in anywhere. |
| 02:44 | Take care when you are using a full length page in your website, the die function will cut off the rest of the code. So I don't recommend using this. |
| 02:53 | I recommend casing the checks that you already have inside the next statement and not really to kill the script. |
| 03:00 | But you will get the general idea here on how to work on what we are trying to do. |
| 03:06 | We need to just type a query that specifies taking a record with a particular username. |
| 03:12 | So, I will say "namecheck query" here. I will call the variable "$namecheck" and this will be a mysql query. |
| 03:21 | I will select "username" for simplicity. This is not going to select all the data. |
| 03:27 | So, I am selecting username from "users" |
| 03:35 | since that's our table name here. |
| 03:39 | I am going to say "WHERE username" is equal to... If we look up here, username of the person that submits the form is in the variable name "username". |
| 03:50 | So, we can just come down here and type "username" now. |
| 03:55 | Now if we choose the name "alex", this would select every record in the database that has the username "alex" and we can see there's one at the moment. |
| 04:09 | Now if I were to specify in this case, with only one record. |
| 04:15 | If I were to specify the username as "Dale", for example, no records will be returned. |
| 04:20 | So therefore, the username won't exist, if no records would be returned. So we need a function to check how many records are returned. |
| 04:29 | You can do this by creating a $count variable. It's "mysql num rows". |
| 04:36 | It just returns the amount of records or rows that are contained within your query which is called "$namecheck". |
| 04:47 | So, let's just test this. I am going to echo out $count and then kill the script. |
| 04:53 | The rest of the code does not execute. |
| 04:57 | Let's go back to Register and I'll type my full name as "alex". |
| 05:03 | Fullname, then choose an username. I am going to choose "Dale". |
| 05:10 | The password won't be checked so we could skip that. |
| 05:16 | But I will just put them here for the sake of it and click Register. |
| 05:24 | We see that we have got a value of zero that is returned. |
| 05:28 | That's because "Dale" is not actually in the database as a 'username'. |
| 05:32 | However, if I change this to "alex", that will be a small "a". |
| 05:39 | We have got some strip tags. The way to deal with case sensitivity as well, is.... so, this is another pointer.. |
| 05:49 | When we are taking the 'username' into account, what we are going to say "string to lower" here, just to make sure that this will always convert to lowercase. |
| 06:01 | Next we are going to... let me find it.... Click Register. |
| 06:08 | We can see that the value of one is returned. |
| 06:12 | So, the check that we were looking for here is - if this variable we are echoing out, is not equal to zero,..then we need to tell the user that the username is already registered. |
| 06:25 | So, here we can create a simple if statement and our block. |
| 06:29 | Then we can say, if our '$count' doesn't equal zero, meaning there is a record present under this condition where the 'username' is already specified... |
| 06:40 | ...then we can just kill the script and say "Username already taken!" or any other message. Coming back here, let's refresh. |
| 06:50 | We can choose "alex". Let me type in a password and click Register. |
| 06:56 | You can see that we have got "Username already taken!" error. |
| 07:00 | If I was to type "Dale" and choose a new name and password and click Register, we can see that it has been successfully registered into the database because the 'username' does not exists. |
| 07:15 | So, I will leave it at that. You can see that we have got our registered user in. |
| 07:22 | Add a "str to lower" function which is a really useful thing to keep everything simple. |
| 07:29 | Or you can just use a "str to lower" function in your if statement. |
| 07:32 | However, to keep it simple I would recommend that you convert all usernames into lowercase. |
| 07:39 | You need to incorporate that into a login script as well. You need to convert whatever the user is typing into the login box to lowercase. |
| 07:48 | I encourage you to play around with it. That's a good way to find some errors. |
| 07:53 | Try them but if you do need any help, please email me. Make sure you subscribe for updates. |
| 07:58 | Thanks for watching. This is Aravind, dubbing for the Spoken Tutorial project. |
