Difference between revisions of "PHP-and-MySQL/C4/User-Login-Part-2/English-timed"

|I mean this error here.

|And we have seen that if we don’t type data we will get an error.

|Now. First of all I’m going to setup a query.  

|So here we are going to say, "SELECT", in fact we’re going to say "SELECT *" because we need the ID, the username and the password.  

|I don’t think we need the id but "SELECT *" anyway so that it will grab all the data.

|So "SELECT * FROM" and we’ve called this, users, I think. Let me confirm that.

|Yes, users.  So "SELECT * users" and here we’ll say "WHERE username" which is the name of this...... this, here.  

|Now if that "username" doesn’t exist, we need to display some kind of an error message to say that "This user doesn’t exist".

|So what we will do is we will use another function, a mysql function called "mysql num rows".  

|So we’ll say "numrows equals mysql_num_rows" and in the brackets we have the name of our query, the variable that I have stored the query function in.

|And if we echo out the number of rows, I’ll just prove to you and test for myself that we should get 1 because we have just 1 row.

|Let me click insert and add another row of data, for example - another username and another password.

|I’ll just try that now. I’ll be testing this later on. Lets see, lets say username is "Kyle" and password is "123" this time.

|Okay, lets try that. And there we are. Hold on a second.  Where am I?  Ah there we go.  

|We can see the ids have been automatically incremented.  

|You can see both our passwords here and the 2 usernames.  

|03.06

|But if I’m saying "SELECT where the username equals my username", we’re obviously only selecting where my username exists and that is in 1 row.  

|Usually on a website, you won’t have duplicate username.  

|Now the purpose is that we can say "if num_rows is equal to zero", then that means we can.. Sorry, if "my num_rows doesn’t equal zero", then we can execute the code we need to do, that we will need to login.

|04.01

|Otherwise, sorry "else", we need to echo out, sorry  "else die". We will give the message "That user doesn’t exist".

|So what we’re doing is, we’re checking that a row has been returned where we have supplied that username.  

|Otherwise we’ll say die and "Tthat username doesn’t exist".  

|So if it is equal to 0, that basically means that no result can be returned.  

|I’ll resend this.  Let’s go back.

|And.........  let’s get rid of our "echo num_rows".

|Now let me use Billy, for example, and type the password in and click on login.  

|"That user doesn’t exist!" because no rows that have the username equal to Billy have been returned.  

|So we can see that that’s working.  

|Inorder to login, we need to perform a password check.  

|So to grab the password, I’ll use a function.  

|Sorry not a function, I’ll use...... a loop and that loop will be the "while" loop.  

|I will type a variable name here. I’ll call it "row" and that is equal to "mysql"..... "mysql_ fetches a row as an array". Okay?  

|So I’ll say "mysqul_fetch_assoc" for short.

|And this is going to be my query.  So I’ve got my query there.  

|From this, we are fetching each column data from here and putting it into an array called "row".  

|So obviously with the while loop, we’ll have our brackets and now we’ll set some variables.  

|I’ll say "db username", which is the username that I’ll extract from the database, is equal to the "row" and this is the row name, "username".  

|So as we can see here, this is the row name here.  

|If this is an array of the data, then each of these are going to be id, username and password.  

|So the database username will be "row" and that since this is an array which is using this function on our query.  

|Next we will say "db password equals row" and then our password.

|So after this we could echo out....  

|No, in fact we don’t need to echo out our contents of our db username and password unless we want to run into errors.

|It’s very simple to do this using an "if" statement.

|"if" our username equals our db username and our password is equal to our db password , then we’ll say it’s correct.

|I will remove the brackets because there is only one line. So echo "Incorrect password!".  Just leave it like that.  

|And here we’ll say echo "You’re in!".  

|Okay we’ll just test this before I end this part of the video.  

|So we’ve checked our username and it exists.  

|We’ve checked our fields exist so please enter in your username and password.  

|If we enter in a username and a wrong password we get an error message – "Incorrect password".  

|And if we enter a username that is not found, we get an error message saying the user doesn’t exist.  

|Okay so join me in the next part, and I’ll show you how to create your sessions and your log out page. See you then!

|This is Antara dubbing for the Spoken Tutorial project.