This chapter focuses on learning about single and multistatement transactions and the read committed isolation level.

Welcome to Transactions and Error Handling in PostgreSQL

Transaction structure

Making our first transaction

Multiple statement transactions

Transaction sizes and PostgreSQL protections

Using and making transactions

Single statement transactions

Isolation levels

Selecting isolation levels

Using an isolation level

Isolation levels and transactions

Getting to Know Transactions

How to rollback when an error is encountered in a transaction block and setting savepoints.

Handling mistakes

Using rollbacks

Multistatement Rollbacks

Rolling back to a savepoint

Working with a single savepoint

Rolling back with a savepoint

Multiple savepoints and rollback

Multiple savepoints

Savepoints and rolling back

Understanding outcomes

Isolation levels, savepoints, and rollbacks

Working with repeatable read

Isolation levels comparison

Savepoint's effect on isolation levels

Rolling Back and Savepoints

In this chapter, you'll learn about exceptions and how to handle them.

Catching exceptions

Writing do statements

Using exception handling wisely

Handling exceptions

Rollbacks, savepoints, and exceptions

Multiple exception blocks

Understanding rollbacks and savepoints

Specific exception handling and messages

Capturing specific exceptions

Logging messages on specific exceptions

Graceful exception handling

When to use graceful degradation

Graceful degradation

Handling Exceptions

With stacked diagnostics, you can get all the information available from PostgreSQL about an exception.

Enhancing exception handling with stacked diagnostics

Getting stacked diagnostics

What data is available in stacked diagnostics

Hints to help handle nested exceptions

Capturing a context stack

Options

Yes, use stacked diagnostics

Don't use stacked diagnostics

When to add custom exception logging and recording

Mixing it all together with debugging functions

Creating named functions and declaring variables

Stacked diagnostics function structure

Structure of stacked diagnostics function

Putting it all together

Wrapping it up

Stacked Diagnostics

FFEIC data

Being able to leverage transactions and find and handle errors is critical to building resilient SQL scripts and working with databases. Transactions provide the protection needed to ensure that your data is consistent and operations work on the desired data in concurrent environments. Improper error handling can cause many serious and unexpected issues. Without the proper use of transactions and error handling, it's possible to make decisions based on incorrect data leading to false outcomes. In this course, we'll cover proper ways to use transactions and handle errors with a record of what went wrong. Additionally, we discuss how concurrently plays into the use of transactions and data outcomes. We'll practice these concepts on the FFEIC bank health data and with a patient data table.

Data Manipulation in SQL

Ensure data consistency by learning how to use transactions and handle errors in concurrent environments.

Transactions and Error Handling in PostgreSQL

`CREATE OR REPLACE FUNCTION` and start the body

`DECLARE` variables and `BEGIN` SQL statements

GET STACKED DIAGNOSTICS and store in variables

Structure of stacked diagnostics function

Transactions and Error Handling in PostgreSQL

Hands-on interactive exercise