Im not even sure if this is possible (Im new to php)
Anyway, what I want to do is this:
mysql_query("SELECT * FROM user_table WHERE concat(username,'#',domain)='$username' LIMIT=1");
Ok, so the $username is an email address that is submitted by a user to search the database to check that they exist. In the user_table usernames are not stored in a single column, they are stored in several with the domain and the actual username being separate.
for example username could be bob and the domain could be website.com.au
Then when the user wants to search for that user the type in bob#website.com.au
This goes to the query above.
So, should it work or not? If not how can I make this work or what suggestions do you have for me?
As BobbyJack has mentioned, this is a slow way of locating a user record.
If you cannot store email address in a single column and place an index on that column, split the string in PHP and make your query:
SELECT * FROM user_table WHERE `username` = '$username' AND `domain` = '$domain'
You could then create a unique index combining domain + username so you wouldn't need LIMIT 1
probably worded the question slightly wrong.
Anyway this is what I have done "SELECT * FROM virtual_user WHERE concat_ws('#',username,domain)='$username'"
I no longer need to use the LIMIT=1, I probably never needed to as all results in the table are individual, so it will always only return a limit of 1 or nothing at all.
It isn't slow in my opinion, but then again Im not really sure what to compare it to. We have about 7000+ records it sorts through so yeah. Is there anyway to get it to tell you how long the query took to complete?
I would like to put both the username and domain into just a single indexed field but its for a postfix mail server and I'm not allowed or game to play with the queries it uses. Especially not on a functioning server that actually handles mail.
Related
I have a database where I'm getting a random row from a table depending on a few variables. I'm trying to make it so it adds their username in this format (Admin, Jerry, Ben) once they view the advertisement (My project - clients view ads for Bitcoin). I want to make it so that once they view it , it adds their name in to a row called users_viewed_add (example is above). I need it to only get random rows based on if their username does not exist in the row users_viewed_add atoll so they can't view the ad more than once.
At the moment, I'm trying to do:
$query_second = mysqli_query($con, "SELECT * FROM business_advertisments WHERE ($users_credits >= amount_per_click) AND (users_viewed_add) NOT LIKE '$username' AND users_name != '$username' ORDER BY RAND() LIMIT 1");
As you can see, the AND (users_viewed_add) NOT LIKE '$username' is not working for me as it's reading the text as a whole word. The problem is that I'm using comma's to seperate the usernames of the clients who have viewed the ad. Is there any work around for this ? I know the method to check a block of text but it wouldn't work in a SQL statement I'm pretty sure.
You can do:
AND CONCAT(',', users_viewed_add, ',') NOT LIKE '%,$username,%'
But you probably want to make a separated many to many table, and use user id instead of user name.
If you want to use multiple values in your LIKE comparison, you can use:
AND users_viewed_add NOT LIKE ALL ('$username')
This will check that none of the $username values exists in the users_viewed_add field. You may need to format your variable properly so the SQL works.
I found the answer from this post: How do I add multiple "NOT LIKE '%?%' in the WHERE clause of sqlite3 in python code?
The correct SQL syntax to check a word doesn't exist in a row is:
AND users_viewed_add NOT REGEXP '[$username]'
I am looking for the best way to write out a php/mysql query to create unique user id's rather than using the autoincrement method in mysql.
Ex: Facebook gives users a long string of numbers as a user id when singing up before you can assign a username. This string of numbers can be used to view your profile OR you can use username. I want users to be able to change username in the future, so don't want to design my system based on username.
I don't know how big the site will get, so please take that into consideration with the solution. I don't want something that is going to be server intensive if there are alot of users signing up.
There isn't really a best route for something like this. Essentially you need to ask yourself what your system requires. You may be able to use an email address as the ID, an auto-incremented number, MD5 hash, or even a heavy-entropy GUID.
Keep in mind that email addresses may change, auto-incremented numbers can be leveraged in automated exploits, and there's technically some chance of hashes colliding.
If you decided to go the route of generating a high-entropy GUID using PHP, you could do so using a function like uniqid.
echo uniqid(); // 513ac40699d85
echo uniqid("_", true); // _513ac3e00bfe46.78760239
The second line shows the two arguments you can provide; a prefix, and a request for more entropy, which will result in a more unique result.
You should follow some algorithm like this:
Enter your new user into the database.
Get the record ID
Generate the userID
Insert the userID next to the name into the sql database.
Enter your new user into the database.
//get username from previous form
$user=$_POST['user'];
// login into mysql server and prepare data for writing
$connect=mysql_connect('localhost', $user, $pass);
$selectdb = mysql_select_db('mydb');
$query = "insert into users_table set
username='$user';";
$run_query=mysql_query($query);
Get the record ID
$id=mysql_insert_id();
Generate the userID
$first_chars=substr($user, 2);
$year=date('y');
$new_user_id= $first_chars.$year.$id;
Insert the UserID next to the name into the sql database
$query="update users_table set userid='$new_user_id' where id='$id';";
$run_query=mysql_query($query);
if (!$run_query) {
echo mysql_error();
}
else {
echo 'your user name is '.$user.' and user id is '.$new_user_id ; }
You can use mysql as a database. Wampserver combines everything and makes it easy. However, i'm not sure if I can help you very much because your question is very vague. Add some more detail please.
Use a hexdigest like sha or md5 to generate an id something like sha1($uname+$timestamp+$salt)
By doing this your will be storing a lot of data for each entry as sha1 takes up 40 bytes.You have already mentioned that the site is may go big,making it a huge amount of data.Decide whether its worth that lot of space.
PS:you can always slice the string,but the collision chance is more that way.
Is there a way I can select from the database the entries with certain data? I got a lot of email addresses in the database but I want to select only from one domain. Is it even possible?
Sure - just use the LIKE operator.
SELECT email FROM Persons
WHERE email LIKE '%gmail.com'
You are not advisable to do a wildcard search.
This is because mysql not able to use index to fasten the select query.
Especially you mention you have lots of email in the database.
Alternatively, you can use an additional field, as hostname to store just the hostname only.
And of course build an index to it.
If you need to search for email with gmail.com,
then you can do straight string comparison
SELECT email FROM Persons
WHERE hostname='gmail.com';
As the straight string comparison is the good mate to mysql index, your query will be optimized.
As ajreal points out, MySQL can't use indexes to optimise a LIKE query in the general case. However in the specific case of a trailing wildcard where the only % is at the very end of the pattern (effectively a "starts with" query), the optimiser can do a good job of speeding up the query using an index.
Therefore, if you were to add an additional indexed column storing the email address in reverse, you could efficiently query for
SELECT email FROM xyz WHERE reverse_email LIKE 'moc.liamg#%`
to find all gmail addresses, or LIKE 'ku.% for all addresses under uk domains, etc. You can have the database keep this column up to date for you using triggers, so it doesn't affect your existing update code
CREATE TRIGGER emailinsert BEFORE INSERT ON xyz
FOR EACH ROW SET NEW.reverse_email = REVERSE(NEW.email);
CREATE TRIGGER emailupdate BEFORE UPDATE ON xyz
FOR EACH ROW SET NEW.reverse_email = REVERSE(NEW.email);
You need to use LIKE MYSQL CLAUSE
SELECT * FROM email_table WHERE email LIKE "%gmail.com"
Hi everyone I want make sure the username is unique!
First I get there username and check if existing already. If not add them to the database, but if the username is taken I will add number behind it.
Example: JoshSmith, JoshSmith1
If there is no username the user still use the id version. I will get there first and last name. And then repeat the above steps.
The problem: If JoshSmith is taken I will add number behind it, but if JoshSmith1 is also taken.
If I use
SELECT count(*) FROM users WHERE username LIKE '%JoshSmith%'
it will return names like JoshSmithing and this is wrong. If I use
MATCH () AGAINST ()
returns the same results.
First I thought to count how many times the username exist and add the number+1
JoshSmith14
But that will be wrong.
You can use regular expressions to filter JoshSmith[numbers] and find biggest number. But, as for me, this is bad way, as you will have a lot of loading to your DB server. I think that it would be better to store counts in some table (especially if correct numbers are important to you).
I got a user table containing 15+ million records and while doing the registration function i wish to check whether the username already exist. I did indexing for username column and when i run the query "select count(uid) from users where username='webdev'" ,. hmmm, its keep on loading blank screen finally hanged up. I'm doing this in my localhost with php 5 & mysql 5. So suggest me some technique to handle this situation.
Is that mongodb is good alternative for handling this process in our local machine?
Thanks,
Nithish.
If you just want to check that it exists or not, try not using the count. Just a simple select username from users where username='webdev' LIMIT 1 may be faster.
ALSO, change the column type to varchar, if it's not already so. Don't user text type. It's much much slower.
This might be a moot point, but to test and see if the user name already exists, I would issue the following query (a slight modification on shamittomar's query):
SELECT DISTINCT `username` FROM `users` WHERE `username` = 'webdev';
This will, by default, return the only instance of "webdev" in the "username" column; if you add more parameters, though, it could change your results. An example being, if you run
SELECT DISTINCT `user_id`, `username` FROM `users` WHERE `username` = 'webdev';
it would return all unique combinations of "user_id" and "username".
One thing you can do is change the indexing of the username from index to unique that will make the search much much faster and like shamittomar said add a limit 1 at the end even though it will only help if the value already exists.
your user name is unique so you must set limit of 1 in your query it will be more faster
select count(uid) from users where username='webdev' limit 1