Something that all of these tools (?) are missing are tutorials around concurrency, allowing multiple sessions to be in progress, interfering with each others o

Something that all of these tools (?) are missing are tutorials around concurrency, allowing multiple sessions to be in progress, interfering with each others operation. TBH this is an under-taught area of databases in general. I have vague ideas about building a browser-based tool that allowed the user to queue up operations to be performed in order in multiple concurrent database sessions, allowing exact locking & blocking behaviour to be experimented with, but have never had time to work on this.