We've covered some many new concepts in this chapter. You learned what transactions are, what the ACID properties are, and how they're enforced by the databases.
You could see that, unfortunately, each database product has its own view about how transactions should be implemented, and you learned about the most important features provided by some of the database systems. You then experimented with a few transaction examples that demonstrated transactions.
The chapter ended by previewing a few advanced topics that enhanced your understanding about how database transactions work. In the next chapter, you'll learn about users and security.