CST 363 Week 5

CST 363 Week 5

This week I learned about how transactions and ACID properties are used in a DBMS. The acronym ACID stands for Atomic, Consistent, Isolation, and Durable. I learned about a logical unit of work within a transaction.

I then explored concurrency problems that can occur with multiple users updating a database concurrently. These problems include dirty reads, nonrepeatable reads, and phantom reads. It was then learned that locking is a way to avoid concurrency issues. I learned about the various isolation levels for locking and how to avoid a deadlock. These isolation levels in order of the weakest to strongest locking are Read Uncommitted, Read Committed, Repeatable Read, and Serializable. I also learned about the differences between optimistic and pessimistic locking.

SQL views were also explored this week. It was learned that this is a good way to create different views that may be used later within a DBMS. I learned about the properties of SQL views and how to implement the syntax for an SQL view in MySQL. Views may be used to hide data, hide complicated syntax, and ensuring consistent results from multiple developers working on a single database.