transaction log for database project

I am working on a database project for school and I was wondering about the best way to add a transaction log to the program. I need to be able to add a line to this log every time I add a new item to a table, every time I delete or edit an item, and various actions need to add a line if certain conditions are not met in one of the processes. Each error generated anywhere in the program also needs to add a line to this log. I also need to be able to view this log from within the program.

I was trying to update the current table and log table at the same time and have been having problems. Any help would be greatly appreciated.