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ER-Diagram Symbols
Above you see the atomic building blocks of the ER-Diagram: Entity Attribute Relation Carninalities (Crow’s feet notation) one, zero-or-one, zero-or-many, one-or-many, many. From Requrements to Deployment ER-Diagram This ER-Diagram is inspired by some of the tables in his sample database Database Implementation Here are Ben Forta’s tables in PhpMyAdmin “design viewW. During implementation you […]
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Video: What is (a) Database & SQL?
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Adminer – a lightweight alternative to PhpMyAdmin
PhpMyAdmin is powerfull but the GUI is messy. Adminer is a lightweight alternative. You have to download the files and place them in your folder. # sudo apt-get isntall adminer # sudo ln -s /usr/share/adminer/ adminer The first line will install the files. They are saved in /usr/share/adminer. Therefore we need a symbolic link to […]
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SQL count(): The Most Popular Cake
This post contiues the SQL tutorial on the Shire Bakery. Here we’ll So how do yo find the most popular cake in the Shire Bakery? Here’s an idea. — Show the best cookie — See: Ben Forta Chap. 16 SELECT COUNT( cakes.cake ) AS ‘popular’, cakes.cake, costumers.who FROM cakes, costumers, likes — sort out the […]
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SQL: Many-to-Many and One-to-Many
Here’s a short tutorial on how to solve some basic SQL cardinalities. First have a look at the ER-diagram for the database and the resulting tables in PhpMyAdmin. Many-to-Many Many to many cardinalities may be solved like this: SELECT cake, who FROM cakes, costumers, likes WHERE costumers.costumers_id = likes.costumers_id AND cakes.cakes_id = likes.cakes_id Note that […]