This is an interesting video on how to speed up your mysql db. Be sure you have an hour of free time if you want to watch this.
If you want to look for more videos on how to to tech stuff I recommend you take a look at bestechvideos

The Quick and Easy Guide to Speed Up MySQL for Web Developers from Jonathan Levin on Vimeo.

I’m working with criteria quite often lately and must say it is a handy way of query writing. The only problem I have with criteria is that I don’t seem to find a simple overview (list) of the most important methods you can add to it. I don’t really like the Propel website as I don’t find the thing I need in a few seconds and that is a must for a lot of people. If I create a list of the most important criteria methods for myself, I rather share it with you guys…

Simple Select query with 2 criteria to check:

$c = new Criteria();
$c->add(AuthorPeer::FIRST_NAME, "Karl");
$c->add(AuthorPeer::LAST_NAME, "Marx", Criteria::NOT_EQUAL);
$authors = AuthorPeer::doSelect($c);
// $authors contains array of Author objects

In SQL this will be:

SELECT ... FROM author WHERE author.FIRST_NAME = 'Karl' AND author.LAST_NAME <> 'Marx';

It’s quite simple to write the criteria, the only thing needed to write them is a list of options.

To add Or to the criteria that have to be checked write:

$cton1 = $c->getNewCriterion(AuthorPeer::FIRST_NAME, 'Karl');
$cton2 = $c->getNewCriterion(AuthorPeer::LAST_NAME,  'Marx', Criteria:: NOT_EQUAL);

// combine them
$cton1->addOr($cton2);

In SQL this will be:

SELECT ... FROM author WHERE author.FIRST_NAME = 'Karl' OR author.LAST_NAME <> 'Marx';

Quite simple isn’t it, and the usage of criteria is quite readable once you start knowing all the options.

Possible operators for criteria (write them like Criteria::Equals)

• EQUAL (default)
• NOT_EQUAL
• GREATER_THAN
• LESS_THAN
• GREATER_EQUAL
• LESS_EQUAL
• LIKE
• NOT_LIKE
• IN
• CUSTOM

This allows you to write your own condition as second parameter.

• CUSTOM_EQUAL

This is used to write a custom condition in an UPDATE query

• ISNULL
• ISNOTNULL

For some methods you need to add a line to the criteria to specify if they have to be used or not:

$c->setIgnoreCase(true);
This is to specify if the query should be case sensitive or not.

$c->addJoin(ReviewPeer::BOOK_ID, BookPeer::ID, Criteria::INNER_JOIN);
INNER JOIN (default) the table in parameter 1 to the table in parameter 2. In the same way you can RIGHT or LEFT JOIN.

$c->addAscendingOrderByColumn(table::column);
This will add an ascending order for the specified column. Off course you can to the opposite too by using addDescendingOrderByColumn.

$criteria->addSelectColumn(self::LABEL);
This will add only this column to the select statement, by default he selects all fields of a table (default *)

All info about the methods and constants of criteria can be found here.

A lot of people seem to have problems with updating or inserting data in tables in an intelligent way. We shouldn’t point a finger to those who don’t use the correct syntax for the problem it solves, because there are a lot of different ways to do this, but I wanted to create a little list of interesting syntax’s that are often forgotten and never used. I will talk about:

• insert… on duplicate key update
• replace
• insert… select
• Load data infile and select into outfile
• delayed

When starting with SQL a few years ago I always executed a query to get a row out of a table and then updated or insert a row in a second query. Of course there are better solutions for this problem according to the specific action you want to do:

INSERT… ON DUPLICATE KEY UPDATE
In this case it is possible for anyone to insert a row in a table, but if the key of this row already exists, it updates a specific value:

INSERT INTO table (a,b,c) VALUES (1,2,3) ON DUPLICATE KEY UPDATE c=c+1;

REPLACE
Replace works exactly like insert, except that if a row already exists, for the unique index or primary key, it is first deleted and then inserted as a new row.
If you have a table where there is no primary key or index, the replace statement makes absolutely no sense, as there will be nothing to delete.

REPLACE INTO table_1 SET a=1, b=2;

The difference between on duplicate key and replace is:
‘Insert … on duplicate key update’ does an insert or an update.
‘Replace’ does and insert with a possible delete first.

INSERT … SELECT
This will insert rows from one or more tables into another table quickly, again to avoid the fact that you should write to queries to execute this.
Use ‘ignored’ in the syntax to ignore duplicate-key violations

LOAD DATA INFILE and SELECT … INTO OUTFILE
‘Load data infile’ will read data from a file into table at very high speed and ‘select into outfile’ will do the exact opposite, writing data from a table to a file.

DELAYED
When you have users on your application that don’t have the time to wait this is a very handy option for the insert statement. It is generally known that the insert statement takes a lot of time during the execution of it, and with this option you can create the opportunity for your user to directly go on with other actions. The insert will only be queued until the table isn’t being used by another thread. Another benefit is that huge inserts can be executed at once and this will result in a much faster execution time.

As we are growing we are in need for a new junior developer to create and maintain websites. If you or someone you know is interested in this job feel free to contact us. The company is Step-@-Site and we are located in Brussels (Vorst/Forest). Our portfolio contains websites/newsletters/intranet sites for small and big companies, for example;

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Your profile:

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While the serialize/unserialize functions exists since the early PHP 4 version, I ignored its existence. I discovered it recently doing some research on how to store multiple data in 1 database field.

Before continuing, keep in mind that it’s not always recommended to store multiple data in a database field, because it will be very difficult, if not impossible, to create queries using the inserted data. All serialized data will have to be unserialized, which takes time.

But why did I use it ?

The website I work on has a widget system (like netvibes and igoogle). Each widget has default settings that can be altered by a user. Those changes need to be saved in a database, so the next time the user loads the widget it will make use of the new settings.

When I first had to create this, I did not know of serialization in php, so I created the following db structure. (trying to respect DB Normalization).

widget and settings

You can see that I have a table with a list of widgets and a list of possible settings. Those two tables are connected to a widgetSetting table where the value of a setting to a widget is stored. It worked perfectly but it is not so proficient :

* To retrieve a widget’s settings, you need to join 2 tables.
* To insert new widget settings, you need to check the settings table if a setting exists or not.
* When updating widget settings, you need to check if a setting is still used or not.

This is a lot of work and database complexity for something that only is used for saving/retrieving settings of a widget. In my case it would be much better if I could save those settings in 1 field in the widget table.

widget

This is how I serialize my settings :

$settings = array(
'itemsOnPage' => 30,
'showChart' => true,
'startDate' => '01-10-2008',
'endDate' => '31-10-2008'
);

$serializedSettings = serialize($settings);

/**
* outputs:
*
* a:4:{s:11:"itemsOnPage";i:30;s:9:"showChart";b:1;s:9:"startDate";s:10:"01-10-2008";s:7:"endDate";s:10:"31-10-2008";}
*
*/

The serialize function will generate a storable representation of my array.
Just save this string in a database field and the job is done. To rebuild the original array from this value you only need to call the unserialize function:

 $storedRepresentation = 'a:4:{s:11:"itemsOnPage";i:30;s:9:"showChart";b:1;s:9:"startDate";s:10:"01-10-2008";s:7:"endDate";s:10:"31-10-2008";}';
$settings = unserialize($storedRepresentation);

/*
* print_r($settings) would give :
*
* Array
* (
*  [itemsOnPage] => 30
*  [showChart] => 1
*  [startDate] => 01-10-2008
*  [endDate] => 31-10-2008
* )
*/

As you can see the unserialize function correctly rebuild the original array.

It is also possible to serialize Objects with the exception of the built-in objects.

class MySettings {

private
$itemsOnPage = 30,
$showCart = true,
$startDate = '01-10-2008',
$endDate = '31-10-2008';

public function getItemsOnPage() {
return $this->itemsOnPage;
}
}

$mySettingsSerialized = serialize(new MySettings());

$mySettings = unserialize($mySettingsSerialized);

echo $mySettings->getItemsOnPage(); // 30

When serializing objects, PHP will attempt to call the member function __sleep() prior to serialization. This is to allow the object to do any last minute clean-up, etc. prior to being serialized. Likewise, when the object is restored using unserialize() the __wakeup() member function is called.

class MySettings {

private
$itemsOnPage = 30,
$showCart = true,
$startDate = '01-10-2008',
$endDate = '31-10-2008';

public function getItemsOnPage() {
return $this->itemsOnPage;
}

public function __wakeup() {
$this->itemsOnPage *= 10;
}
}

$mySettingsSerialized = serialize(new MySettings());

$mySettings = unserialize($mySettingsSerialized);

echo $mySettings->getItemsOnPage(); // 300

So you see it is very simple to use the seriailize/unserialize functions in php. But like I said in the beginning of the post, use it wisely when storing the serialized value in a database. I only use it when I do not need the value for creating sql queries.