Beginning Database Design Solutions

Chapter 17. Introduction to SQL

Eventually you (or someone else) must actually build the database that you've designed. Also at some point, someone will probably want to actually use the database you've spent so much time designing.

SQL (pronounced "sequel") includes commands that let you build, modify, and manipulate a database. Chances are SQL will be used either directly or behind the scenes to create and use the database. Even tools such as MySQL, Access, and SQL Server that let you interactively build a database also allow you to use SQL.

SQL is also directly useful for creating and initializing a database. In fact, it's so useful that it's the topic of the next chapter.

SQL is such an important part of database development that your education as a database designer is sadly lacking if you don't at least understand the basics. (The other developers will rightfully mock you if you don't chuckle when you see a tee-shirt that says, "SELECT * FROM People WHERE NOT Clue IS null.")

In this chapter you learn how to use SQL to:

• Create and delete tables.

• Insert data into tables.

• Select data from the database using various criteria and sort the results.

• Modify data in the database.

• Delete records.

Background

SQL, which stands for Structure Query Language, was developed by IBM in the mid-1970s. It is an English-like command language for building and manipulating relational databases.

From a small but ambitious beginning, SQL has grown into a large language containing around 70 commands with hundreds ...