CSV upload, once uploaded to a temp folder overwrite the existing database

[eluser]TheFuzzy0ne[/eluser]
All you're doing is explode()ing the file name. Since that's only a single line, you're array only has a single line, which you're removing with array_shift. You need to open the file in order to obtain any data from it. The array that $this->upload->data() returns is simply information about the uploaded file, not the file itself.

Debug, debug, debug! Check your code each step of the way. Output arrays and strings to make sure they contain the data you think they do.