04 Try it yourself Interactive

Ten statements, and a rollback that arrives too late

One script against the same three students, one statement per press. The top table is what your session sees. The bottom table is what is permanent right now — what another session would read, and what would survive if the power went out on this exact step. Watch the two tables drift apart, come back together, and then watch a DDL statement on line 9 make the drift permanent behind your back. The run follows Oracle and MySQL, where DDL commits; the last step says what PostgreSQL would have done instead. Nothing plays on its own: Next, Back and Reset, or the arrow keys.

One script, four families
10 statements, one session
Green = this step put it there. Indigo = changed, but only in your session. Amber = look here, the two tables disagree. The label top-right names the family of the statement running.
Press Next to begin. Each press runs exactly one statement.


      

        
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Savepoints set0

        
Commits, typed or implicit0

        
Uncommitted row changes0

      


      

      

        
        
        
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