Dynamic SQL queries

dynamic_sql.php

<?php
// ev = escape value
function ev(object $dbh, $value) {
    if (is_null($value)) {
        return 'NULL';
    } else if (is_int($value)) {
        return $value;
    } else if ($value instanceof \DateTimeImmutable) {
        $value = $value->format('Y-m-d');
        # /!\ no return here /!\
    }
    if ($dbh instanceof \PDO) {
        return $dbh->quote($value);
    } else if ($dbh instanceof \mysqli) {
        return "'" . $dbh->real_escape_string($value) . "'";
    } else {
        throw new \Exception("I don't know how to handle an objet of class '" . get_class($dbh) . "'");
    }
}

// ei = escape identifier
function ei(string $identifier): string {
    return '`' . str_replace('`', '``', $identifier) . '`';
}

function update(object $dbh, string $table, array $columns, array $conditions = []): string {
    // SET part
    $set = [];
    foreach ($colonnes as $column => $value) {
        $set[] = ei($column) . ' = ' . ev($dbh, $value);
    }
    // WHERE part
    if ($conditions) {
        $where = [];
        foreach ($conditions as $column => $value) {
            $where[] = ei($column) . (is_null($value) ? ' IS ' : ' = ') . ev($dbh, $value);
        }
    } else {
        $where = ['1=1'];
    }

    return 'UPDATE ' . ei($table) . ' SET ' . implode(', ', $set) . ' WHERE ' . implode(' AND ', $where);
}