Re: Disaster with dash on mysql cli interface
Kevin Old schrieb: Hello everyone, I had a horrible thing happen to me this morning and wanted to make it known to the community. I needed to delete a record from a very large table (yes, it was backed up) and like the cli interface of mysql. I ran this query: delete from tablename where id - 12345; Notice that I accidentally hit the dash (-) instead of the equal (=). It proved to be disasterous as it deleted all the records from that table. Lucky for me I had a backup from last night and not too many records were added since then and I was able to restore. For the record, I am aware of the select before delete method, but didn't use it in this one instance and it meant a few hours restoring data. Just wanted to throw this out and see if others had possible solutions for working with the mysql cli interface for maybe setting up rules for it to cancel a query if it contains a certain character (like the dash). Fat chance there is, but I thought I'd ask. Hope this helps someone, Kevin On this one use LIMIT. If you want to delete specific rows alway use LIMIT. even if you f**k up you just have deleted one row. If you are luck it is an old one and easy restoreable. Barry -- Smileys rule (cX.x)C --o(^_^o) Dance for me! ^(^_^)o (o^_^)o o(^_^)^ o(^_^o) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Disaster with dash on mysql cli interface
On 6/21/06, Barry [EMAIL PROTECTED] wrote: Kevin Old schrieb: Hello everyone, I had a horrible thing happen to me this morning and wanted to make it known to the community. I needed to delete a record from a very large table (yes, it was backed up) and like the cli interface of mysql. I ran this query: delete from tablename where id - 12345; Notice that I accidentally hit the dash (-) instead of the equal (=). It proved to be disasterous as it deleted all the records from that table. Lucky for me I had a backup from last night and not too many records were added since then and I was able to restore. For the record, I am aware of the select before delete method, but didn't use it in this one instance and it meant a few hours restoring data. Just wanted to throw this out and see if others had possible solutions for working with the mysql cli interface for maybe setting up rules for it to cancel a query if it contains a certain character (like the dash). Fat chance there is, but I thought I'd ask. Hope this helps someone, Kevin On this one use LIMIT. If you want to delete specific rows alway use LIMIT. even if you f**k up you just have deleted one row. If you are luck it is an old one and easy restoreable. Hi Barry, So if I understand you correctly, I'd do the following: delete from tablename where id - 12345 limit 1; Is that correct? -- Kevin Old [EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Disaster with dash on mysql cli interface
Hi, On Jun 21, 2006, at 12:24 PM, Kevin Old wrote: On 6/21/06, Barry [EMAIL PROTECTED] wrote: Kevin Old schrieb: Hello everyone, I had a horrible thing happen to me this morning and wanted to make it known to the community. I needed to delete a record from a very large table (yes, it was backed up) and like the cli interface of mysql. I ran this query: delete from tablename where id - 12345; Notice that I accidentally hit the dash (-) instead of the equal (=). It proved to be disasterous as it deleted all the records from that table. Lucky for me I had a backup from last night and not too many records were added since then and I was able to restore. For the record, I am aware of the select before delete method, but didn't use it in this one instance and it meant a few hours restoring data. Just wanted to throw this out and see if others had possible solutions for working with the mysql cli interface for maybe setting up rules for it to cancel a query if it contains a certain character (like the dash). Fat chance there is, but I thought I'd ask. Hope this helps someone, Kevin On this one use LIMIT. If you want to delete specific rows alway use LIMIT. even if you f**k up you just have deleted one row. If you are luck it is an old one and easy restoreable. Hi Barry, So if I understand you correctly, I'd do the following: delete from tablename where id - 12345 limit 1; Is that correct? That still will delete one row, so you still might need a backup to get back that row. Another option you might want to look into is using the --safe- updates option to the command line client. This will prevent you from doing DELETEs and UPDATEs that don't use an index properly. For example, in your case deleting the entire table would have been prevented, whereas the correct id = 12345 would be allowed (assuming id is the PK or index). I generally always use that option on a production machine. It does a few other things as well (LIMIT 1000, max_join_size), so make sure you check it out before using it. It used to be called --i- am-a-dummy mode (that option works too), so you might see it referred to as that in some places. http://dev.mysql.com/doc/refman/5.0/en/safe-updates.html Regards, Harrison -- Harrison C. Fisk, Trainer and Consultant MySQL AB, www.mysql.com Get a jumpstart on MySQL Cluster -- http://www.mysql.com/consulting/ packaged/cluster.html -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Disaster with dash on mysql cli interface
On Wed, 21 Jun 2006 11:12:40 -0400, Kevin Old wrote: Hello everyone, I had a horrible thing happen to me this morning and wanted to make it known to the community. I needed to delete a record from a very large table (yes, it was backed up) and like the cli interface of mysql. I ran this query: delete from tablename where id - 12345; Notice that I accidentally hit the dash (-) instead of the equal (=). It proved to be disasterous as it deleted all the records from that table. Lucky for me I had a backup from last night and not too many records were added since then and I was able to restore. For the record, I am aware of the select before delete method, but didn't use it in this one instance and it meant a few hours restoring data. Just wanted to throw this out and see if others had possible solutions for working with the mysql cli interface for maybe setting up rules for it to cancel a query if it contains a certain character (like the dash). Fat chance there is, but I thought I'd ask. Hope this helps someone, Kevin -- Kevin Old [EMAIL PROTECTED] Doesn't mysql have transactions? If it does you could just start a transaction before you do anything. This is what I do with PostgreSQL. As I recal oracle's sqlplus does this by default. begin; -- or something -- do some stuff -- if you did something dumb rollback; -- or something -- otherwise commit; -- or something -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: Disaster with dash on mysql cli interface
This sounds awfully like doing an rm -rf somefile. * (with an accidental space in between the . and the *). Most unix/linux geeks I know (including myself) only ever do this once. Humans like to learn the hard way, it seems :-) -- boof On Thursday 22 June 2006 03:24, Harrison Fisk wrote: Hi, On Jun 21, 2006, at 12:24 PM, Kevin Old wrote: On 6/21/06, Barry [EMAIL PROTECTED] wrote: Kevin Old schrieb: Hello everyone, I had a horrible thing happen to me this morning and wanted to make it known to the community. I needed to delete a record from a very large table (yes, it was backed up) and like the cli interface of mysql. I ran this query: delete from tablename where id - 12345; Notice that I accidentally hit the dash (-) instead of the equal (=). It proved to be disasterous as it deleted all the records from that table. Lucky for me I had a backup from last night and not too many records were added since then and I was able to restore. For the record, I am aware of the select before delete method, but didn't use it in this one instance and it meant a few hours restoring data. Just wanted to throw this out and see if others had possible solutions for working with the mysql cli interface for maybe setting up rules for it to cancel a query if it contains a certain character (like the dash). Fat chance there is, but I thought I'd ask. Hope this helps someone, Kevin On this one use LIMIT. If you want to delete specific rows alway use LIMIT. even if you f**k up you just have deleted one row. If you are luck it is an old one and easy restoreable. Hi Barry, So if I understand you correctly, I'd do the following: delete from tablename where id - 12345 limit 1; Is that correct? That still will delete one row, so you still might need a backup to get back that row. Another option you might want to look into is using the --safe- updates option to the command line client. This will prevent you from doing DELETEs and UPDATEs that don't use an index properly. For example, in your case deleting the entire table would have been prevented, whereas the correct id = 12345 would be allowed (assuming id is the PK or index). I generally always use that option on a production machine. It does a few other things as well (LIMIT 1000, max_join_size), so make sure you check it out before using it. It used to be called --i- am-a-dummy mode (that option works too), so you might see it referred to as that in some places. http://dev.mysql.com/doc/refman/5.0/en/safe-updates.html Regards, Harrison -- Harrison C. Fisk, Trainer and Consultant MySQL AB, www.mysql.com Get a jumpstart on MySQL Cluster -- http://www.mysql.com/consulting/ packaged/cluster.html -- brendan bouffler Architect, HPC New Technology APJ ESS Competency Lab x: Sydney, Australia, v: +61 404 097 837 mtb: 2003 Tassajara -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
