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Free ebooks
 Free database ebooks SQL Head First SQL - A Brain-Friendly Guide
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 1 - data and tables A place for everythingDon’t you just hate losing things? Whether it’s your car keys, that 25% off coupon for Urban Outfitters, or your application’s data, there’s nothing worse than not being able to keep up with what you need... when you need it. 2 - the SELECT statement Gifted data retrieval you’ll meet the powerful SELECT statement and learn how to gain access to that important information you’ve been putting in your tables. 3 - DELETE and UPDATE A change will do you good With UPDATE, you can change data, and DELETE lets you get rid of data that you don’t need anymore. But we’re not just giving you the tools; in this chapter, you’ll learn how to be selective with your new powers and avoid dumping data that you really do need. 4 - smart table design Why be normal? And that’s fine, they work. You can SELECT, INSERT, DELETE, and UPDATE with them. But as you get more data, you start seeing things you wish you’d done to make your WHERE clauses simpler. What you need is to make your tables more normal. 5 - ALTER Rewriting the Past Well, now is your chance. By using the ALTER command, you can apply all the lessons you’ve been learning to tables you designed days, months, even years ago. Even better, you can do it without affecting your data. 6 - advanced SELECT Seeing your data with new eyes You already know how to SELECT data and use WHERE clauses. But sometimes you need more precision than SELECT and WHERE provide. In this chapter, you’ll learn about how to order and group your data, as well as how to perform math operations on your results. 7 - multi-table database design Outgrowing your table Your single table is full of redundant data, wasting space and slowing down your queries. You’ve gone as far as you can go with a single table. It’s a big world out there, and sometimes you need more than one table to contain your data, control it, and ultimately, be the master of your own database. 8 - joins and multi-table operations Can’t we all just get along? It’s great to have more than one table in your database, but you’ll need to learn some new tools and techniques to work with them. With multiple tables comes confusion, so you’ll need aliases to keep your tables straight. 9 - subqueries Queries within queries Joins are great, but sometimes you need to ask your database more than one question. Or take the result of one query and use it as the input to another query. That’s where subqueries come in. They’ll help you avoid duplicate data, make your queries more dynamic, and even get you in to all those high-end concert afterparties. 10 - outer joins, self-joins, and unions New maneuvers You’ve seen cross joins that return every possible row, and inner joins that return rows from both tables where there is a match. But what you haven’t seen are outer joins that give you back rows that don’t have matching counterparts in the other table, self-joins which (strangely enough) join a single table to itself, and unions that combine the results of queries. 11 - constraints, views, and transactions Too many cooks spoil the database In this chapter we begin protecting our data from the mistakes of others. Welcome to Defensive Databases, Part 1. 12 - security Protecting your assets You’re about to learn how databases and the objects in them can be made more secure, and how you can have complete control over who can do what with your data. Download free pdf ebooks for SQL:Head First SQL - A Brain-Friendly Guide
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