PHP check if value exists

Question

I’m trying to write a if code, but can't figure out how.

In my database table i have the primary key id. In the table i have objekt_nr & element_nr. Now, before i call an INSTERT i need to check if objekt_nr with element_nr already exist. If objekt_nr With element_nr exist. Then UPDATE instead of INSTERT. Only id can be unique.

example of table:

id......objekt_nr......element_nr

1.......1...............1

2.......1...............2

3.......1...............3

4.......2...............1

5.......2...............2

PHP:

if(isset($_POST["Import"])){
echo '<a href=".php">Fortsätt...</a><br />';
echo $path=$_FILES["file"]["tmp_name"];

//Load file into PHPExcel
$objPHPExcel = PHPExcel_IOFactory::load($path);

//Loop threw file to get data
foreach ($objPHPExcel->getWorksheetIterator() as $worksheet) {
    $worksheetTitle     = $worksheet->getTitle();
    $highestRow         = $worksheet->getHighestRow(); // e.g. 10
    $highestColumn      = 'J'; //$worksheet->getHighestColumn(''); // e.g 'F'
    $highestColumnIndex = PHPExcel_Cell::columnIndexFromString($highestColumn);
    $nrColumns = ord($highestColumn) - 64;

//Echo file info
echo "<br>The worksheet ".$worksheetTitle." has ";
echo $nrColumns . ' columns (A-' . $highestColumn . ') ';
echo ' and ' . $highestRow . ' row.';
echo '<br>Data: <table border="1"><tr>';

//Loop threw colum, rows and cells
for ($row = 2; $row <= $highestRow; ++ $row) {
    echo '<tr>';
    for ($col = 0; $col < $highestColumnIndex; ++ $col) {
        $cell = $worksheet->getCellByColumnAndRow($col, $row);
        $val = $cell->getCalculatedValue();
        //$dataType = PHPExcel_Cell_DataType::dataTypeForValue($val);
        echo '<td>' . $val . '<br></td>';
    }
    echo '</tr>';
}
echo '</table>';
}

for ($row = 2; $row <= $highestRow; ++ $row) {
$val=array();
for ($col = 0; $col < $highestColumnIndex; ++ $col) {
$cell = $worksheet->getCellByColumnAndRow($col, $row);
$val[] = $cell->getCalculatedValue();
}
// Prepare Query 
    $query = "INSERT INTO phpexcel(
                objekt_nr,
                objekt_rev,
                element_nr,
                element_hojd,
                element_typ,
                element_langd,
                element_oppningar,
                element_vikt,
                element_ritare,
                element_status) 
            VALUES ( 
            :objekt_nr, 
            :objekt_rev, 
            :element_nr,
            :element_hojd,
            :element_typ,
            :element_langd,
            :element_oppningar,
            :element_vikt,
            :element_ritare,
            :element_status
        )"; 

    // Security measures
    $query_params = array(  
        ':objekt_nr' => $val[0],
        ':objekt_rev' => $val[1],
        ':element_nr' => $val[2],
        ':element_hojd' => $val[3],
        ':element_typ' => $val[4],
        ':element_langd' => $val[5],
        ':element_oppningar' => $val[6],
        ':element_vikt' => $val[7],
        ':element_ritare' => $val[8],
        ':element_status' => $val[9]
    ); 
    try {  
        $stmt = $db->prepare($query); 
        $result = $stmt->execute($query_params); 
    } 
    catch(PDOException $ex){ die("Failed to run query: " . $ex->getMessage()); } 


//echo $query."\n";
}
}

Answer 1

Two options here.

1) Make "objekt_nr" field a PRIMARY or UNIQUE key and use REPLACE instead of INSERT (http://dev.mysql.com/doc/refman/5.0/en/replace.html). This is pretty much @hd 's answer in the comments.

2) Check for an existing "objekt_nr" and "element_nr" and run the appropriate query

$check_duplicate_query = "SELECT COUNT(*) FROM phpexcel WHERE objekt_nr = ':objekt_nr' AND element_nr = ':element_nr'";
$stmt = $db->prepare($check_duplicate_query);
$result = $stmt->execute($query_params);
$rows = $stmt->fetch(PDO::FETCH_NUM);

if($rows[0] > 0) {
    //UPDATE
} else {
    //INSERT
}

$stmt = $db->prepare($query); 
$result = $stmt->execute($query_params); 

EDIT:

Just thought of a 3rd option

Create another field "objekt_element_nr" and set this field to unique. This field gets assigned objekt and element number combination, which from your example should be unique.

e.g. 1_1, 1_2, 1_3, 2_1, 2_2, etc.

Then simply use the REPLACE function I linked to above.

Your $query_params would look like

$query_params = array(  
        ':objekt_nr' => $val[0],
        ':objekt_rev' => $val[1],
        ':element_nr' => $val[2],
        ':objekt_element_nr' => $val[0].'_'.$val[2]
        ':element_hojd' => $val[3],
        ':element_typ' => $val[4],
        ':element_langd' => $val[5],
        ':element_oppningar' => $val[6],
        ':element_vikt' => $val[7],
        ':element_ritare' => $val[8],
        ':element_status' => $val[9]
    );