Question

I am stuck with a peculiar issue here. I have a script that basically imports a CSV file into a database using fgetcsv() in php. There is no problem in doing this at all and I am able to update old entries as well using MySQL syntax ON DUPLICATE KEY UPDATE (I am in no way a MySQL expert, hence me asking here).

Here is that part of the code:

$handle = fopen($file,"r");
fgetcsv($handle, 1000, ",");//skip first row since they are headers
while(($fileop = fgetcsv($handle, 1000, ",")) !== false) //read line by line into $fileop
{
  //read array values into vars
  $item1 = $fileop[0];
  $item2 = $fileop[1];
  $key = $fileop[2];
  // and a couple more

  // now INSERT / UPDATE data in MySQL table
  $sql = mysql_query("INSERT INTO table (item1,item2,key) 
    VALUES ('$item1','$item2','$key') 
    ON DUPLICATE KEY UPDATE item1='$item1',item2='$item2'");

}

This all works fine. What I am stuck with is the fact that some entries may have been removed from the actual CSV (as in the key may no longer be existant). What I would like to do is remove the entries from the MySQL table that are no longer present in the CSV.

Meaning if $key is gone from CSV also remove that row in the database table. I suppose I would do it before I run the Insert / Update query on the MySQL table?

I would appreciate any help guys.

Answer 1

Just keep an account of your keys.

Save every $key in an array in your while, and in the end run a query that says

DELETE FROM tabel WHERE key NOT IN (listofcommaseparatedkeysgoeshere)

---

$arrayThatYouNeedToTest = array();
$handle = fopen($file,"r");
fgetcsv($handle, 1000, ",");//skip first row since they are headers
while(($fileop = fgetcsv($handle, 1000, ",")) !== false) //read line by line into $fileop
{
  //read array values into vars
  $item1 = $fileop[0];
  $item2 = $fileop[1];
  $key = $fileop[2];
  // and a couple more

  // now INSERT / UPDATE data in MySQL table
  $sql = mysql_query("INSERT INTO table (item1,item2,key) 
    VALUES ('$item1','$item2','$key') 
    ON DUPLICATE KEY UPDATE item1='$item1',item2='$item2'");

   $arrayThatYouNeedToTest[] = $key;    

}

$stringThatYouNeedToInspect = implode(",",$arrayThatYouNeedToTest);
$queryYouREALLYneedToCheckFirst = "DELETE FROM tabel WHERE key NOT IN  (".$stringThatYouNeedToInspect.")";

//$result = mysql_query($queryYouREALLYneedToCheckFirst);