I am new in forum, and need some help to do one functionality for my unity game. I am trying to save the progress of the player in one mysql database, like this:
userid level stars
29 1 2
29 2 1
45 1 3
50 1 2
50 2 3
50 3 1
29 3 3
so the script send the userid provided by the user registration in the begining of the game. and for each level he complete, the script send the number of the level, and the amount of stars collected in the level..
the problem and question is, how I configure this in the php script and mysql database to save the information only once? because if the player with the id 50 play the first level, will add a line with the information, but if the same player play the first level again and change the amount of stars, I dont want a new line, just update the stars amount.
I take a look in the INDEX, UNIQUE, PRIMARY, FULLTEXT, SPATIAL functions but dont figured out what is the correct combination and how to put in the php script, and take a look in other questions in the forum but nothing like this.
thanks for the help!
I recommend you use http://redis.io/ (in-memory data structure store, used as database, cache and message broker) to save progress in the games.
First you want an unique index on the combination (userid, level) and then you want to do an update if the combination exists and an insert otherwise.
For how to create the unique index please take a look at How do I specify unique constraint for multiple columns in MySQL?
For how to code the SQL query to do update/insert please take a look at SQL: If Exists Update Else Insert
The article above uses Microsoft SQL syntax. In PHP you can code this by issuing the query and then using mysql_affected_rows to see how many rows where affected. If 0 rows where affected then you issue the INSERT query from PHP.
in pseudo code you need to do something like this in SQL.
UPDATE $table set column=value WHERE id=$ID
Hi brayan actually the problems is that no one will write code for you, you have to do it yourself. I guess you are unaware with SQL i.e., you asked that
how I configure this in the php script and mysql database to save the
information only once? because if the player with the id 50 play the
first level, will add a line with the information, but if the same
player play the first level again and change the amount of stars, I
dont want a new line, just update the stars amount.
Anyhow You first required some basic understanding of SQL and PHP with Unity. I will recommend you this Guide Server_Side_Highscores of unityWiki it help you to make database and server logic intergartion with PHP.
Now for your Second important part of question.
You have to update user code after each level completion.Or you can simply ask to user about socre save.
Before inserting new record into the database you have to check that userId with level id alread exist or not. some thing like this
Select userid, level, stars
from youTableName
where userid = ?
and level = ?
if the above query return empty response then you simply need to add the record
INSERT INTO table_name (userid, level, stars)
VALUES (value1,value2,value3);
Otherwise you have to update that specific column.
Related
I'm having trouble figuring out an efficient way to register a big number of data in my database, using php/mysql.
I have a list of phone numbers, which are stored in a number table.
PHONE_ID | PHONE_NUMBER | COUNTRY_ID
varchar
And a table linking a phone number with a "contact list group". Let's assume it's name is link_phonegroup.
For each phone/group link, I have a parameters list.
GROUP_ID | PHONE_ID | PARAMETERS_LIST
varchar
My script should be able to, given a group_id, compute through millions of numbers and :
retrieve the number_id associated with the number OR insert the number if it does not exist (and return the insert_id)
update the parameters_list associated with this group/number pair and if this pair does not exist, insert it
Currently, I loop (foreach) through my numbers, and, foreach number :
SELECT PHONE_ID FROM number WHERE PHONE_NUMBER = '$number'
If it does not exist, I INSERT INTO ... and retrieve this newly created id with mysql_insert_id()
Then, with this ID, I SELECT PARAMETERS_LIST FROM link_phonegroup WHERE GROUPE_ID = $group_id AND PHONE_ID = $phone_id.
If it does exist, I then UPDATE my parameters list, and if it does not, I INSERT a new row inside my link_phonegroup table.
My problem, as you may imagine, is that for each of my X millions numbers, I will fire 4 queries. That is slow, inefficient, and scary.
I learned about the INSERT INTO ON DUPLICATE KEY technique (MySQL manual page). My tests were super-slow, and i gave up.
I learned about the UPDATE CASE WHEN technique (Example).
Basically, my current goal is to fire ONE query each 200-ish loop (200 is a random number here, i'll do some tests with other values), which would insert/update/retrieveid/insert_into_this_other_table/make_me_a_sandwich/and_dont_forget_coffee, in a few words do all the work, which - I HOPE ! - will be a faster and less stressfull method for the database.
Is this the good way to go ? Is this the best way to go ?
And if it is, what would be the skeleton of this mecha-query-of-death ? I cannot figure out how to insert-or-retrieve the phone ID in the same request of the insert-or-update parameters_list given this phone ID in the same request of a hundreds of other similar requests ?
Is this even possible ?
I hope you understand my nerves here have given up since a long time.
I would be happy and thankful for any help you can give to me.
Thank you.
What you want can be done with stored procedures. I will direct you at a couple of resources first -- since you appear to know a bit about MySQL already it's probably of benefit to you to learn how stored procedures work and code it yourself rather than have someone else just feed you the stored procedure.
http://code.tutsplus.com/articles/an-introduction-to-stored-procedures-in-mysql-5--net-17843
http://www.mysqltutorial.org/mysql-stored-procedure-tutorial.aspx
I have a small PHP function on my website which basically does 3 things:
check if user is logged in
if yes, check if he has the right to do this action (DB Select)
if yes, do the related action (DB Insert/Update)
If I have several users connected at the same time on my website that try to access this specific function, is there any possibility of concurrency problem, like we can have in Java for example? I've seen some examples about semaphore or native PHP synchronization, but is it relevant for this case?
My PHP code is below:
if ( user is logged ) {
sql execution : "SELECT....."
if(sql select give no results){
sql execution : "INSERT....."
}else if(sql select give 1 result){
if(selected column from result is >= 1){
sql execution : "UPDATE....."
}
}else{
nothing here....
}
}else{
nothing important here...
}
Each user who accesses your website is running a dedicated PHP process. So, you do not need semaphores or anything like that. Taking care of the simultaneous access issues is your database's problem.
Not in PHP. But you might have users inserting or updating the same content.
You have to make shure this does not happen.
So if you have them update their user profile only the user can access. No collision will occur.
BUT if they are editing content like in a Content-Management System... they can overwrite each others edits. Then you have to implement some locking mechanism.
For example(there are a lot of ways...) if you write an update on the content keeping the current time and user.
Then the user has a lock on the content for maybe 10 min. You should show the (in this case) 10 min countdown in the frontend to the user. And a cancel button to unlock the content and ... you probably get the idea
If another person tries to load the content in those 10 min .. it gets an error. "user xy is already... lock expires at xx:xx"
Hope this helps.
In general, it is not safe to decide whether to INSERT or UPDATE based on a SELECT result, because a concurrent PHP process can INSERT the row after you executed your SELECT and saw no row in the table.
There are two solutions. Solution number one is to use REPLACE or INSERT ... ON DUPLICATE KEY UPDATE. These two query types are "atomic" from perspective of your script, and solve most cases. REPLACE tries to insert the row, but if it hits a duplicate key it replaces the conflicting existing row with the values you provide, INSERT ... ON DUPLICATE KEY UPDATE is a little bit more sophisticated, but is used in a similar situations. See the documentation here:
http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html
http://dev.mysql.com/doc/refman/5.0/en/replace.html
For example, if you have a table product_descriptions, and want to insert a product with ID = 5 and a certain description, but if a product with ID 5 already exists, you want to update the description, then you can just execute the following query (assuming there's a UNIQUE or PRIMARY key on ID):
REPLACE INTO product_description (ID, description) VALUES(5, 'some description')
It will insert a new row with ID 5 if it does not exist yet, or will update the existing row with ID 5 if it already exists, which is probably exactly what you want.
If it is not, then approach number two is to use locking, like so:
query('LOCK TABLE users WRITE')
if (num_rows('SELECT * FROM users WHERE ...')) {
query('UPDATE users ...');
}
else {
query('INSERT INTO users ...');
}
query('UNLOCK TABLES')
I am curious what path I should take to accomplish the following. I want multiple computers at one location to be able to view and make changes to data inside a mysql DB with a web browser. I dont have extensive knowledge in this area, but from what I do remember this was very difficult if not impossible.
Example: Lets say I have a record for John and I want 2 computers to be able to edit Johns record. Please note that the computers will not be editing the same portion of Johns record. Lets say one record is changing a status from need to be called to called and the other computer is changing the status of need to be ordered to ordered.
I want a solution that could natively handle this.
My current knowledge is building web interfaces with PHP and SQL. I would like to use these languages as I have some prior knowledge.
So my question: Is this possible? If, so exactly how would it work(flow of info)?
There are several ways that you can accomplish this. There's already some great PHP database editing software packages out there (phpMyAdmin).
To handle this in code though you can either use Transactions (depending on what flavor of SQL you're using this would be done differently)
One of the easier ways to ensure that you don't have people's data clashing with one another is just by adding additional where clauses to your statement.
Lets say you have a user record and you want to update the last name from Smith to Bill, and the user ID is 4.
Instead of writing
UPDATE users SET lastName='Bill' WHERE id='4'
You would add in:
UPDATE users SET lastName='Bill' WHERE id='4' AND lastName='Smith'
That way if someone else updates the last name field while you're working on it, your query will fail and you'll have to re-enter the data, thus faking a transaction
Use Transactions. Updating a single record at the exact same time isn't really supported, but applying one transaction followed immediately by another certainly is. This is native to MySQL.
START TRANSACTION;
SELECT #A:=SUM(salary) FROM table1 WHERE type=1;
UPDATE table2 SET summary=#A WHERE type=1;
COMMIT;
One other thing to do is the old desktop approach. Wich is almost mannualy control the flow of modifications. I will show:
Say that you have a client table with the fields id, firstname, lastname, age. In order to control multiple users updates you will add the version integer default 0 field to this table.
When you populate the object on the form to an user you will also store the actual version that the user has selected.
So lets assume that your client table is like this:
id firstname lastname age version
1 Tomas Luv 20 0
2 Lucas Duh 22 0
3 Christian Bah 30 0
When the user select the client with the id=1 the version of this row is, in this moment, 0. Then the user update the lastname of this client to Bob and submit it.
Here comes the magic:
Create a trigger (before update) that will check the current version of that registry with the version that the user previously selected, something like this (this is just pseudo code, as I'm doing it from my head):
create trigger check_client_version on client before update as
begin
if new.version != old.version then
throw some error saying that a modification already was done;
else
new.version = old.version + 1;
end if;
end;
On the application you check if the update has this error and inform to user that someone else made change on the registry he try to change.
So with the given example it would be like:
1 - The user A selected the row 1 and start editing it
2 - At the same time the user B selected the row 1 and save it before the user A
3 - The user A try to save his modifications and get the error from the application
On this context the user A has the version field pointed to 0 also is the user B but when the user B save the registry it now is 1 and when the user A try to save it it will fail because of the check trigger.
The problem with this approch is that you will have to have a before update trigger to every table in your model or at least the one you are concerned with.
I build a like system for a website and I'm front of a dilemma.
I have a table where all the items which can be liked are stored. Call it the "item table".
In order to preserve the speed of the server, do I have to :
add a column in the item table.
It means that I have to search (with a regex in my PHP) inside a string where all the ID of the users who have liked the item are registered, each time a user like an item. This in order verify if the user in question has (or not) already liked the item before. In this case, I show a different button on my html.
Problem > If I have (by chance) 3000 liked on an item, I fear the string to begin very big and heavy to regex each time ther is a like
on it...
add a specific new table (LikedBy) and record each like separately with the ID of the liker, the name of the item and the state of the like (liked or not).
Problem > In this case, I fear for the MySQL server with thousand of rows to analyze each time a new user like one popular item...
Server version: 5.5.36-cll-lve MySQL Community Server (GPL) by Atomicorp
Should I put the load on the PHP script or the MySql Database? What is the most performant (and scalable)?
If, for some reasons, my question does not make sens could anyone tell me the right way to do the trick?
thx.
You have to create another table call it likes_table containing id_user int, id_item int that's how it should be done, if you do like your proposed first solution your database won't be normalized and you'll face too many issues in the future.
To get count of like you just have to
SELECT COUNT(*) FROM likes_table WHERE id_item='id_item_you_are_looking_for';
To get who liked what:
SELECT id_item FROM likes_table WHERE id_user='id_user_you_are_looking_for';
No regex needed nothing, and your database is well normalized for data to be found easily. You can tell mysql to index id_user and id_item making them unique in likes_table this way all your queries will run much faster
With MySQL you can set the user ID and the item ID as a unique pair. This should improve performance by a lot.
Your table would have these 2 columns: item id, and user id. Every row would be a like.
I've got a problem that I just can't seem to find the answer to. I've developed a very small CRM-like application in PHP that's driven by MySQL. Users of this application can import new data to the database via an uploaded CSV file. One of the issues we're working to solve right now is duplicate, or more importantly, near duplicate records. For example, if I have the following:
Record A: [1, Bob, Jones, Atlanta, GA, 30327, (404) 555-1234]
and
Record B: [2, Bobby, Jones, Atlanta, GA, 30327, Bob's Shoe Store, (404) 555-1234]
I need a way to see that these are both similar, take the record with more information (in this case record B) and remove record A.
But here's where it gets even more complicated. This must be done upon importing new data, and a function I can execute to remove duplicates from the database at any time. I have been able to put something together in PHP that gets all duplicate rows from the MySQL table and matches them up by phone number, or by using implode() on all columns in the row and then using strlen() to decide the longest record.
There has got to be a better way of doing this, and one that is more accurate.
Do any of you have any brilliant suggestions that I may be able to implement or build on? It's obvious that when importing new data I'll need to open their CSV file into an array or temporary MySQL table, do the duplicate/similar search, then recompile the CSV file or add everything from the temporary table to the main table. I think. :)
I'm hoping that some of you can point out something that I may be missing that can scale somewhat decently and that's somewhat accurate. I'd rather present a list of duplicates we're 'unsure' about to a user that's 5 records long, not 5,000.
Thanks in advance!
Alex
If I were you I'd give a UNIQUE key to name, surname and phone number since in theory if all these three are equal then it means that it is a duplicate. I am thinking so because a phone number can have only one owner. Anyways, you should find a combination of 2-3 or maybe 4 columns and assign them a unique key. Once you have such a structure, run something like this:
// assuming that you have defined something like the following in your CREATE TABLE:
UNIQUE(phone, name, surname)
// then you should perform something like:
INSERT INTO your_table (phone, name, surname) VALUES ($val1, $val2, $val3)
ON DUPLICATE KEY UPDATE phone = IFNULL($val1, phone),
name = IFNULL($val2, name),
surname = IFNULL($val3, surname);
So basically, if the inserted value is a duplicate, this code will update the row, rather than inserting a new one. The IFNULL function performs a check to see whether the first expression is null or not. If it is null, then it picks the second expression, which in this case is the column value that already exists in your table. Hence, it will update your row with as much as information possible.
I don't think there're brilliant solutions. You need to determine priority of your data fields you can rely on for detecting similarity, for example phone, some kind of IDs, of some uniform address or official name.
You can save some cleaned up values (reduced to the same format like only digits in phones, concatenated full address) along with row which you would be able to use for similarity search when adding records.
Then you need to decide on data completeness in any case to update existing rows with more complete fields, or delete old and add new row.
Don't know any ready solutions for such a variable task and doubt they exist.