RSI using php and mysql database

 For rsi calculation in php and database .

// Step 1: Store Data in Database

store 16 close data in database

// Step 2: Fetch Data from Database

$sqlrsi = "SELECT close FROM $cand ORDER BY id ASC LIMIT 16";

$rdata = $connection->query($sqlrsi);

$closePrices = [];

while($rowrsi = $rdata->fetch_assoc()) {

    $closePrices[] = $rowrsi["close"];

}

// Step 3: Calculate RSI for 14-Period

function calculate_rsi($closePrices, $period = 14) {

    $deltas = [];

    for ($i = 1; $i < count($closePrices); $i++) {

        $deltas[] = $closePrices[$i] - $closePrices[$i - 1];

    }

    $seed = array_slice($deltas, 0, $period);

    $up = 0;

    $down = 0;

    foreach ($seed as $delta) {

        if ($delta >= 0) {

            $up += $delta;

        } else {

            $down += abs($delta);

        }

    }

    $up /= $period;

    $down /= $period;

    $rs = $up / $down;

    $rsi = [100 - 100 / (1 + $rs)];

    for ($i = $period; $i < count($closePrices) - 1; $i++) {

        $delta = $deltas[$i - 1];

        if ($delta > 0) {

            $upval = $delta;

            $downval = 0;

        } else {

            $upval = 0;

            $downval = abs($delta);

        }

        $up = ($up * ($period - 1) + $upval) / $period;

        $down = ($down * ($period - 1) + $downval) / $period;

        $rs = $up / $down;

        $rsi[] = 100 - 100 / (1 + $rs);

    }

    return $rsi;

}

$rsi0 = calculate_rsi($closePrices, 14);

// Output the RSI values

//echo "RSI values: ";

//print_r($rsi);

$rsi = $rsi0["1"];

echo " rsi ". $rsi;