MySQL update rows. Need to update lots of unique rows - mysql

Question

I am using PHP scripts on my mySQL database. What I have is an inventory of products that is being pulled for a search page. I have this working fine, and my search page is working flawlessly. The only thing I cannot figure out is how to update the stock of each product in the database. I have a new file that needs to match up with the product number and then replace the data in one column of the mysql database. Much like this below
mysql database:
ProductNumber..................ProductStock
12345678....................................1
New file:
12345678..................5
Basically I need the new file to match with the product number on the mysql and replace the product stock with the new number. All of this in PHP.

Answer 1

You don't say how many rows you got in that database. Usually individual UPDATEs are pretty slow.
You can
load your "new stocks" file into a temporary table using LOAD DATA INFILE
make an UPDATE using a JOIN to set the values in your products table
This will be a few orders of magnitude faster.
Update with the syntax to use on mysql :
UPDATE products p JOIN temp_products t ON (p.id=t.id) SET p.stock = t.stock;
Note that you need special privileges for LOAD DATA INFILE.
You can also use LOAD DATA INFILE LOCAL (check the docs).
Or, you can parse the file with PHP, generate an INSERT with multi-values in a temp table, and do a joined update. This will be a little slower than LOAD DATA INFILE, but much much faster than doing 27000 queries.

Answer 2

$sql = 'UPDATE table_products SET ProductStock=5 WHERE ProductNumber=12345678';
mysql_query($sql);
So basically: use an UPDATE statement for the database.
How does the file look?

Answer 3

Well you will have to open the file, use explode() and then use preg_match as per the requirements.

Answer 4

You can use mysql's load data local infile to do this. Write a small import script and run it on a cron daily. Is the stock file in csv format?
An example script would be as follows
$dir = dirname(__FILE__) . DIRECTORY_SEPARATOR;
$stock_file = $dir . "files". DIRECTORY_SEPARATOR."stock.csv";
$stock_query = "
load data local infile \"{$stock_file}\"
replace into table products
fields terminated by ',' enclosed by '\"'
lines terminated by '\n'
ignore 1 lines
(ProductNumber,ProductStock);
";
$m->query($stock_query);
Things to consider would be what the fields are terminated by and enclosed by. Also the ignore 1 lines is there to ignore the header row if the file has one.