CSV Bulk Import multiple $duplicateChecks allow combining conditions

[Zauberfisch]

currently the $duplicateChecks check as OR, so lets say you have:

public $duplicateChecks = array('ID' => 'ID', 'Title' => 'Title');

this would basically do a SQL: WHERE ID = $ID OR Title = $Title
but a OR might not always be the desired condition.

lets take a product import:

"Category","Title","Price"
"Food","Unicorn Meat","42"
"Specials","Unicorn Horn","1337"
"Specials","A scale of Zauberfisch","invaluable"
"Food","RandomName","21"
"Specials","RandomName","42"

so, RandomName in Food might be something different than RandomName in Specials, therefor I need to check WHERE Category = $Category AND Title = $Title

but with the current implementation just using

 public $duplicateChecks = array('Category' => 'Category', 'Title' => 'Title');

would not work here, because it would consider a Unicorn Horn a duplicate of A scale of Zauberfisch, which clearly is wrong.

I can workaround using a callback on a single value (eg. Title) and perform both checks in that callback, but shouldn't the CsvBulkLoader be able to to handle this usecase?

what are your thoughts on that? If I get some input and we agree on a way to implement it, I am happy to do it.

[Zauberfisch]

after some conversation in IRC, I think it stands to consider if this even still has a reason to exist.

considering how easy doing this with a datalist is now (->filterAny(array('Title' => $title)))

another point to deprecate this is that it is not consistent and misleading,
I just discovered that 'Name' => 'Title' actually completely ignores Name and only uses Title on both the CSV data as well as in the Database
only when using 'Name' => callback then the Name is used

[Zauberfisch]

followup conversation on IRC:

http://logs.silverstripe.com?date=2013-10-16#log_1081753 line 178-193
http://logs.silverstripe.com?date=2013-10-16#log_1081780 line 205-241

[dhensby]

this was recently raised on SO: https://stackoverflow.com/questions/49281839/how-to-check-duplicatechecks-in-csvbulkloader-silverstripe-by-checking-2-colom/49282404