FrenchTech SAAS

<?php require_once'dbconfig.php'; $customerNumber=103;try{    $conn=newPDO("mysql:host=$host;dbname=$dbname",$username,$password);    // execute the stored procedure    $sql='CALL GetCustomerLevel(:id,@level)';    $stmt=$conn->prepare($sql);     $stmt->bindParam(':id',$customerNumber,PDO::PARAM_INT);    $stmt->execute();    $stmt->closeCursor();    // execute the second query to get customer's level    $r=$conn->query("SELECT @level AS level")->fetch(PDO::FETCH_ASSOC);    if($r){        echosprintf('Customer #%d is %s',$customerNumber,$r['level']);    }}catch(PDOException$pe){    die("Error occurred:".$pe->getMessage());}

You can download the source code via the following link:

PHP MySQL Transaction (1.62 kB)

We use the classicmodels database as a MySQL sample database to help you work with MySQL quickly and effectively. The classicmodels database is a retailer of scale models of classic cars database. It contains typical business data such as customers, products, sales orders, sales order line items, etc.

We use this sample database in our MySQL tutorials to demonstrate many MySQL features from simple queries to complex stored procedures.

Suppose you want to find out employee whose last name starts with character M, B or T. You can use a regular expression in the SELECT statement as follows:

SELECT lastname, firstname FROM employees WHERE lastname REGEXP '^(M|B|T)';123SELECTlastname,firstnameFROMemployeesWHERElastnameREGEXP  '^(M|B|T)';

Let me take an example. You would think think that using a UNIQUE or PRIMARY KEY on a text-based column (using something like a VARCHAR or CHAR type) in a table would ensure that any two strings are unique, but that two strings values that are different may coexist in two different rows. Think again.

There are many cases where you can apply the GROUP_CONCAT function to produce useful results. The following list is some common examples of the using the GROUP_CONCAT function.

Use GROUP_CONCAT function to make a comma-separated user’s roles such as ‘admin,author,editor’.Use GROUP_CONCAT function to return the comma-separated user’s hobbies e.g., ‘design,programming,reading’.Use GROUP_CONCAT function to build a tag for blog posts, articles or products e.g., ‘mysql, mysql aggregate function, mysql tutorial’.

In MySQL, views are not only read-only but also updateable. However in order to create an updateable view, the SELECT statement that defines the view has to follow several following rules:

The SELECT statement must only refer to one database table.The SELECT statement must not use GROUP BY or HAVING clause.The SELECT statement must not use DISTINCT in the column list of the SELECT clause.The SELECT statement must not refer to read-only views.The SELECT statement must not contain any expression (aggregates, functions, computed columns…)

When you create updateable views, make sure that you follow the rules above.

MySQL provides several useful statement that allows you to maintain database tables effectively. Those statements enable you to analyze, optimize, check, and repair database tables.

In data migration, we often have to compare two tables and identify a record in one table that have no corresponding record in another table.

For example, we have a new database whose schema is different from the legacy database. Our task is to migrate all data from the legacy database to the new one and verify that the data were migrated correctly. In order to check the data, we have to compare two tables, one in the new database and one in the legacy database, and identity the unmatched records.

Sometimes, you have to select random records from a database table, for example:

Select some random posts in a blog and display them in the sidebar.Select a random quote for displaying “quote of the day” widget.Select random pictures in a gallery and use the as the featured pictures.

On peut faire remonter l’usage informel des diagrammes de Voronoï jusqu'à Descartes en 1644 dans Principia philosophiae comme illustration de phénomène astronomique 1.Dirichlet a utilisé des diagrammes de Voronoï en dimension 2 ou 3 dans son étude des formes quadratiques en 1850 (Dirichlet 1850).

Le médecin britannique John Snow a utilisé un diagramme de Voronoï en 1854 pour montrer que la majorité des personnes mortes dans l’épidémie de choléra de Soho vivait plus près de la pompe infectée de Broad Street que de n’importe quelle autre pompe.

Les diagrammes de Voronoï portent le nom du mathématicien russe Georgy Fedoseevich Voronoï (ou Voronoy) qui a défini et étudié le cas général en dimension n en 1908. Les diagrammes de Voronoi qui sont utilisés en géophysique et en météorologie pour analyser des données de distributions spatiales (comme les mesures de chutes de pluie) sont appelés polygones de Thiessen du nom du météorologiste américain Alfred H. Thiessen (en).