Database Tutorial

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This tutorial shows you how to create tables in Oracle, MySQL, and SQL Server (future version). While the general guidelines of SQL are the same, implementation drives differences. Like ordinary languages, these variations are known as dialects.

SQL dialects can be subtle or distinct. MySQL has made a conscious effort to stay very close to the ANSI SQL stantards. As of MySQL 5.1, the product is now ANSI SQL:92 compliant. Oracle also makes an effort to be compliant with the ANSI SQL standards. As of Oracle 11g, the product is ANSI SQL:2003 compliant. However, Oracle includes components that aren’t defined in the standard, like hierarchical queries. Microsoft SQL Server likewise tries to meet standards but also simultaneous supports a proprietary set of products. As a result, Microsoft delivers T-SQL (known as Transact-SQL, which is a distinct accent apart from the other two. Part of this distinct flavor is due to the legacy Sybase code, while others have a long history within Microsoft development approaches and products.

Database Constraints

This explains the five types of database constraints in relational databases. Click on the link above to see the details of the check, foreign key, not null, primary key, and unique constraints.

The balance of examples for creating, modifying, and dropping tables are found in the DDL web pages.

Written by michaelmclaughlin

January 14th, 2018 at 12:56 am

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