mysql

Ruby: would using Fibers increase my DB insert throughput?

Currently I am using Ruby 1.9.1 and the 'ruby-mysql' gem, which unlike the 'mysql' gem is written in ruby only. This is pretty slow actually, as it seems to insert at a rate of almost 1 per second (SLOOOOOWWWWWW). And I have a lot of inserts to make too, its pretty much what this script does ultamitely. I am using just 1 connection (sinc...

How to name uploaded files in php to prevent them from being overwritten?

I'm trying to add user submitted articles to my website, (only for admins). With each article comes an option to upload up to 3 images. My database is set up like this Articles id user_id title body date_added last_edited Photos id (auto_increment) article_id First I save the article in the database, then I upload the photo (tempo...

php MySQL snytax error

my scrip is supposed to look up contacts in a table and present thm on the screen to then be edited. however this is not this case. I am getting the error Parse error: syntax error, unexpected $end in /home/admin/domains/domain.com.au/public_html/pick_modcontact.php on line 50 NOTE: this is the last line in this script. <? session_star...

nginx-tornado-django request timeout

We are using nginx-tornado-django to provide web services. That is, no web page frontend. The nginx server serves as a load-balancer. The server has 8 cores, so we launched 8 tornado-django processes on every server. Memcached is also deployed to gain better performance. The requests per day is about 1 million per server. We use MySQL as...

How do I dump only results of one table in a database in MySQL and replicate to another remote empty table with the same structure?

It's a long sentence, anyone knows? ...

How do I select a random record efficiently in MySQL?

mysql> EXPLAIN SELECT * FROM urls ORDER BY RAND() LIMIT 1; +----+-------------+-------+------+---------------+------+---------+------+-------+---------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+------+---------...

Database performance benchmark

Any good articles out there comparing Oracle vs SQL Server vs MySql in terms of performance? I'd like to know things like: INSERT performance SELECT performance Scalability under heavy load Based on some real examples in order to gain a better understanding about the different RDBMS. ...

In SQL, can we always write an inner join statement as a main query and subquery if we only want to find the intersection?

In SQL, can we always write an inner join statement as a main query and subquery or vice versa if we only want to find the intersection? For example, select * from gifts g where g.giftID in (select giftID from sentGifts); can do a join and show the gifts sent in the sentGifts table, but it won't be able to show the sentTime because ...

Is it possible that one of the mysql queries would interrupt?

I really didn't know how to call the topic, but I will try to explain it here. So, for example, I have 6 queries in one page. Is it possible, that first five of them would be completed and the last one wouldn't be? Is there any possibilities? If there is, what should I do? Hope you understood smth. Thanks. ...

In SQL, in what situation do we want to Index a field in a table, or 2 fields in a table at the same time?

In SQL, it is obvious that whenever we want to do a search on millions of record, say CustomerID in a Transactios table, then we want to add an index for CustomerID. Is another situation we want to add an index to a field when we need to do inner join or outer join using that field as a criteria? Such as Inner join on t1.custumerID = t...

mysql DB import/export command line in windows

How to export / import database in mysql through comman line, mysql system config , WAMPSERVER server installed . OS WINDOWS The advise for my local host , not an live hosting... Thanks ...

Is using Natural Join or Implicit column names not a good practice when writing SQL in a programming language?

When we use Natural Join, we are joining the tables when both table have the same column names. But what if we write it in PHP and then the DBA add some more fields to both tables, then the Natural Join can break? The same goes for Insert, if we do a insert into gifts values (NULL, "chocolate", "choco.jpg", now()); then it will bre...

smallest mysql type that accomodates single decimal

Database newbie here. I'm setting up a mysql table. One of the fields will accept a value in increment of a 0.5. e.g. 0.5, 1.0, 1.5, 2.0, .... 200.5, etc. I've tried int but it doesn't capture the decimals. `value` int(10), What would be the smallest type that can accommodate this value, considering it's only a single decimal. I...

Hibernate pojo file issues

Hi all I am currently using netbeans for a project. I have created my db using MySQL Workbench. I have two relationships that are one to one. However once I create the POJOs using netbeans hibernate mapping files tools they are being created as one to many. I have tried reversing the db within workbench and the relationships are shown...

mySQL 1046 error when importing wordpress database

I'm moving a locally developed wordpress site to a client's server so I'm trying to export the local database and import it to the server. I exported the .sql file according to the instructions here http://codex.wordpress.org/Backing_Up_Your_Database but I keep getting this error when importing: DROP TABLE IF EXISTS `wp_commentmeta` ; ...

Complicated idea - how to create car racing for my RPG game's players

So, I want to create car racing for my RPG game's players. Player can create race and choose how many participants can participate in race. After race is being created, other people can join it. When the maximum participants are collected, race begins. My idea, when the last participant joins, then instantly choose the winner (who's ca...

PHP + MySQL transactions examples

I really haven't found normal example of PHP file where MySQL transactions are being used. Can you show me simple example of that? And one more question. I've already done a lot of programming and didn't use transactions. Can I put a PHP function or something in header.php that if one mysql_query fails, then the others fail too? ...

general things developer must know having 2+ years of exp?

Hi All, I have 2 years of experience in Ruby on Rails. I have basic knowledge (very bsic) of mysql such as data insertion, join, select from more than one table. But now I want to know more about it because my friends are having trouble in interviews when they are asked questions like: What is the trigger? which trigger is called whe...

Sorting MySQL results within a resultset

I have a resultset of lets say 10 results. 3 of them have a type 'Pears', and the next 3 have a type 'Apples' and the next three have a type of 'Bananas'. The last record has a type of 'Squeezing Equipment' - unrelated to the fruits. How do I return this set of results (for pagination too) in a GROUPED order that I specify WITHOUT using ...

How to determine the difference among dates in the same column?

How to determine the difference among dates of birth? +----------+----------+------------+ | id | name | birth | +----------+----------+------------+ | 00001 | Claws | 2010-04-17 | | 00002 | Claws | 2010-01-31 | | 00003 | Claws | 2009-11-31 | | 00004 | Claws | 2009-09-31 | | 00005 | Claws | ...