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I just use psql. psql> \i changes.sql The file, changes.sql in this case, might look like this: begin; alter table t1 add column c ...; alter table

I just use psql. psql> \i changes.sql The file, changes.sql in this case, might look like this: begin; alter table t1 add column c ...; alter table t2 drop column d ...; alter table t3 alter column e ...; drop view if exists v; create view v as select ... ; rollback; I save the file in version control with the rollback statement, for safety. When I am ready to run it, I temporarily change "rollback" to "commit". If I wanted to test out just some of the statements, I would comment out the others. EDIT: You can inspect the changes in flight by inserting a select-statement: begin; alter table t1 alter column c ...; select * from t1 where ... ; rollback; (Interesting, Hacker News's user interface puts no reply link below your comment. So I could not reply directly. I guess it allows only so many nested replies. This is probably an optimization for readability or to avoid flamewars).

eyelidlessness 6y ago
That's great, but the statefulness of trying something is still a problem. It would still be nice to be able to wrap a whole change or set of changes with a guarantee that I'll be able to view the outcome without a state change in the database. This nicety is compounded by the fact that I'm often working with datasets that take a few hours to get set up before I can even evaluate. There are a ton of other guard rails I can set up to make that turnaround less shitty, but even cloning a backup database in the worst case is painful. There's no reason the expressiveness of SQL can't embrace complex expressions as a single statement to encapsulate a whole transaction in a single expression. CTEs already do most of that, they just don't have any transactional capability. Edit: I also don't just use psql, because having normal editing controls that I'm used to in my operating system is muscle memory I leverage and also error prone if I try to use the wrong tool with the wrong muscle memory. I know how to move a caret around every single Mac app, but it works differently the moment I enter anything other than emacs in my terminal.
eyelidlessness 6y ago
> You can inspect the changes in flight by inserting a select-statement All true, but you still can't express a transaction as a single expression. > Interesting, Hacker News's user interface puts no reply link below your comment. So I could not reply directly. I guess it allows only so many nested replies. This is probably an optimization for readability or to avoid flamewars They just hide the reply link at a certain depth of threading. You can navigate to the parent comment (by parent link or datestamp depending) and reply.

eyelidlessness 6y ago

That's great, but the statefulness of trying something is still a problem. It would still be nice to be able to wrap a whole change or set of changes with a guarantee that I'll be able to view the outcome without a state change in the database. This nicety is compounded by the fact that I'm often working with datasets that take a few hours to get set up before I can even evaluate. There are a ton of other guard rails I can set up to make that turnaround less shitty, but even cloning a backup database in the worst case is painful. There's no reason the expressiveness of SQL can't embrace complex expressions as a single statement to encapsulate a whole transaction in a single expression. CTEs already do most of that, they just don't have any transactional capability. Edit: I also don't just use psql, because having normal editing controls that I'm used to in my operating system is muscle memory I leverage and also error prone if I try to use the wrong tool with the wrong muscle memory. I know how to move a caret around every single Mac app, but it works differently the moment I enter anything other than emacs in my terminal.

eyelidlessness 6y ago

> You can inspect the changes in flight by inserting a select-statement All true, but you still can't express a transaction as a single expression. > Interesting, Hacker News's user interface puts no reply link below your comment. So I could not reply directly. I guess it allows only so many nested replies. This is probably an optimization for readability or to avoid flamewars They just hide the reply link at a certain depth of threading. You can navigate to the parent comment (by parent link or datestamp depending) and reply.