ttheimer
asked on
Generating an INSERT statement from a SELECT before deleting
I want to give customers the ability to delete data on a web site (LAMP). Before each deletion I would like to generate and store an INSERT statement that could be used to restore the data if the deletion was in error.
I would guess that this is a common need and I was hoping that there are known functions, instruction sets, or a php class that already exists to do this. I haven't found anything in my searching so far. Does anyone know of such a script?
Thanks.
Tom
I would guess that this is a common need and I was hoping that there are known functions, instruction sets, or a php class that already exists to do this. I haven't found anything in my searching so far. Does anyone know of such a script?
Thanks.
Tom
ASKER
Thanks AngryBinary. Translating from TransSQL to PHP and SQL is more work than I was hoping for. If I have to build my own script I may use this as a model but I still believe somebody has done this for the LAMP environment and I'll wait for a reference to appear.
Tom
Tom
I don't know the requirements of your application but I suggest you mark the 'deleted' field as deleted. If the delete was an error, remove the mark. Because if you perform a delete operation, and need to use INSERT, you'll need the data source again which will give you overwork.
If this didn't help, please enlight me
If this didn't help, please enlight me
What kind of error it might be?
If it's db's exception, then you should use transaction for your delete queries.
Something like this
begin transaction
try {
delete
}
catch {
rollback
}
For data safety, I think you should use logical deletion machanism instead of physical deletion machanism.
Each record has a delete flag.
When user deletes a record, the flag is updated to 'true' and that record won't be shown up again.
Then you have a script that automatically deletes deleted records periodically.
If it's db's exception, then you should use transaction for your delete queries.
Something like this
begin transaction
try {
delete
}
catch {
rollback
}
For data safety, I think you should use logical deletion machanism instead of physical deletion machanism.
Each record has a delete flag.
When user deletes a record, the flag is updated to 'true' and that record won't be shown up again.
Then you have a script that automatically deletes deleted records periodically.
Sorry I missed Shanksben's post.
What he said is what I mean logically deletion machanism.
What he said is what I mean logically deletion machanism.
ASKER
Shanksben, if I were redesigning this application from scratch I would do exactly as you recommend. But to retrofit a "deleted" field means that I would need to locate and modify every SELECT and UPDATE query that uses the modified table so that a record is not included in the query result if it has been marked as deleted. Because I am just adding the restore functionality to an existing site I want to use a more localized approach. Storing records as INSERT statements before deleting is a simple and universal approach.
dsmile, our customers have the ability to add and delete employees. When they opt to delete we warn that it is usually a better option to de-activate but there are conditions in which deletion is the right choice. But every month or two we will receive a call from a customer stating that they accidentally deleted an employee two days or two weeks ago. Therefore a rollback is not an option because of the delay between the deletion and the recognition that a mistake had been made.
dsmile, our customers have the ability to add and delete employees. When they opt to delete we warn that it is usually a better option to de-activate but there are conditions in which deletion is the right choice. But every month or two we will receive a call from a customer stating that they accidentally deleted an employee two days or two weeks ago. Therefore a rollback is not an option because of the delay between the deletion and the recognition that a mistake had been made.
Hope this helps http://www.tech-recipes.com/rx/1475/save-mysql-query-results-into-a-text-or-csv-file/
You run this command before each delete query with output filename named base on time & delete condition (maybe with customer info also, so you can trace back)
You run this command before each delete query with output filename named base on time & delete condition (maybe with customer info also, so you can trace back)
ASKER
dsmile, INTO OUTFILE and INTO DUMPFILE both generate a new file with each use and the result is a tab delimited file (OUTFILE). I'm looking for a "production" solution that can create the INSERT statement which I would programmatically drop it into a table each time a customer calls the delete option. And I'm still hoping that someone else has worked out the code to construct the INSERT stmt.
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I also suggest you this quick tutorial (in case this is new to you):
http://www.mysqltutorial.org/create-the-first-trigger-in-mysql.aspx
Regards
http://www.mysqltutorial.org/create-the-first-trigger-in-mysql.aspx
Regards
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