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Times I've Messed Up as a Developer

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Re: Times I've Messed Up as a Developer

#11

Post by 1ba9115454 »

megaman22 wrote: post #8
1ba9115454 wrote: post #2

Back in the early 90's I had 2 terminals up on my X windows console. One for local dev and another for a production server running a trading system for around 50 users. Naturally for production I was logged in as root. I typed rm -rf to clear out my dev folder only to figure out I just deleted the root folder and all sub folders on a production machine. I recalled a piece of advice a university friend had given me. "…

Did anyone ever notice that it happened?

No one. It was lunchtime and it's possible no ne traded so far that day.

Re: Times I've Messed Up as a Developer

#12

Post by Spoom »

donatj wrote: post #7

I was on my way out the door at my first job, and an SEO person stopped me and asked me if I could fix something. I just needed to delete a single row from a database. Easy enough. I get as far as “DELETE FROM table_name” and for some unknown reason run the damn thing without a WHERE. All the rows, gone! We did have nightly backups but the guy with access to them was notoriously hard to get the attention of and lived…

Always write DELETEs as SELECTs, and once you run the SELECT and it returns the rows you want, then swap out the SELECT * with a DELETE.

Re: Times I've Messed Up as a Developer

#13

Post by mfoy_ »

Spoom wrote: post #12
donatj wrote: post #7

I was on my way out the door at my first job, and an SEO person stopped me and asked me if I could fix something. I just needed to delete a single row from a database. Easy enough. I get as far as “DELETE FROM table_name” and for some unknown reason run the damn thing without a WHERE. All the rows, gone! We did have nightly backups but the guy with access to them was notoriously hard to get the attention of and lived…

Always write DELETEs as SELECTs, and once you run the SELECT and it returns the rows you want, then swap out the SELECT * with a DELETE.

It sounds silly, but that makes a lot of sense. Lots of tips for me to take away from this thread. :)

Re: Times I've Messed Up as a Developer

#14

Post by wonderwonder »

Spoom wrote: post #12
donatj wrote: post #7

I was on my way out the door at my first job, and an SEO person stopped me and asked me if I could fix something. I just needed to delete a single row from a database. Easy enough. I get as far as “DELETE FROM table_name” and for some unknown reason run the damn thing without a WHERE. All the rows, gone! We did have nightly backups but the guy with access to them was notoriously hard to get the attention of and lived…

Always write DELETEs as SELECTs, and once you run the SELECT and it returns the rows you want, then swap out the SELECT * with a DELETE.

That's a really great idea.

Re: Times I've Messed Up as a Developer

#15

Post by amyjess »

Spoom wrote: post #12
donatj wrote: post #7

I was on my way out the door at my first job, and an SEO person stopped me and asked me if I could fix something. I just needed to delete a single row from a database. Easy enough. I get as far as “DELETE FROM table_name” and for some unknown reason run the damn thing without a WHERE. All the rows, gone! We did have nightly backups but the guy with access to them was notoriously hard to get the attention of and lived…

Always write DELETEs as SELECTs, and once you run the SELECT and it returns the rows you want, then swap out the SELECT * with a DELETE.

That's good advice in general, not just for SQL.

For example, I often write my 'rm' commands as 'ls' at first and then swap out the command once I know it gets the right thing.

Re: Times I've Messed Up as a Developer

#16

Post by _ea1k »

Spoom wrote: post #12
donatj wrote: post #7

I was on my way out the door at my first job, and an SEO person stopped me and asked me if I could fix something. I just needed to delete a single row from a database. Easy enough. I get as far as “DELETE FROM table_name” and for some unknown reason run the damn thing without a WHERE. All the rows, gone! We did have nightly backups but the guy with access to them was notoriously hard to get the attention of and lived…

Always write DELETEs as SELECTs, and once you run the SELECT and it returns the rows you want, then swap out the SELECT * with a DELETE.

That is really good advice. I have also found that it is good to do this with file delete commands (ls before rm).

Re: Times I've Messed Up as a Developer

#17

Post by acomjean »

You're likely going to mess up sometime. Have a backup plan.

I too have "restored" a database to the wrong server (production was now development). This was a member list for an arts organization... After about 20 minutes of panic (what is going on....) I remembered I had set daily backups. whew.

Re: Times I've Messed Up as a Developer

#18

Post by fapjacks »

amyjess wrote: post #15
Spoom wrote: post #12

Earlier quoted context omitted.

Always write DELETEs as SELECTs, and once you run the SELECT and it returns the rows you want, then swap out the SELECT * with a DELETE.

That's good advice in general, not just for SQL. For example, I often write my 'rm' commands as 'ls' at first and then swap out the command once I know it gets the right thing.

Yes, I learned this from a sysadmin in the early 90s and did this when learning to use Unix and having used the technique in various other contexts (e.g. database DELETEs), I am confident this one weird trick has saved me from catastrophic mistakes countless times.

Re: Times I've Messed Up as a Developer

#20

Post by LanceH »

donatj wrote: post #7

I was on my way out the door at my first job, and an SEO person stopped me and asked me if I could fix something. I just needed to delete a single row from a database. Easy enough. I get as far as “DELETE FROM table_name” and for some unknown reason run the damn thing without a WHERE. All the rows, gone! We did have nightly backups but the guy with access to them was notoriously hard to get the attention of and lived…

I did this on the users table in production but I was fortunate enough to have started a transaction. I was just about shaking when I typed 'rollback'.

The fact that I was entering a delete -- instead of setting to inactive and doing it in production from the command line should give you an idea of how likely the backups would have been effective. This was in '97, though when everything was seat of the pants during the full internet craze.

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