If else in sql insert - php

Question

I want to make a code where if the data already exists in the database and the user insert the same input again and send to the database, the sql command will detect it and will not allow the duplicate data enter the database. Addtional information, I don`t have primary key for my table. Here is my code.
$sql="INSERT IGNORE INTO tempahan(Nama,Aktiviti,No_HP,Unit,Tempat,Tarikh_Penggunaan,Masa_Mula,Masa_Akhir,Email) VALUES('$_POST[name]','$_POST[Aktiviti]','$_POST[number]','$_POST[unit]','$_POST[tempat]','$_POST[tarikh]','$_POST[masa1]','$_POST[masa2]','$_POST[email]')";
$_POST['tempat'] = $data['Tempat'] ;
$_POST['masa1'] = $data['Masa_Mula'];
$_POST['masa2'] = $data['Masa_Akhir']; if($_POST['tempat'] != $data['Tempat'] && $_POST['masa1'] != $data['Masa_Mula'] && $_POST['masa2'] != $data['Masa_Akhir']) {
echo 'the booking was successful.';
}
else
{ echo 'the place already occupied.';}
I'm new to sql and also php. Therefore, I really need help from all of you guys. I already see the other same question. But, every solution provided I've failed.

Answer 1

The correct way to do this is to enforce a unique constraint on your table, across the fields that you consider to be unique. You can do that as such.
alter table tempahan
add unique (Tempat, Masa_Mula, Masa_Akhir)
Your database will then reject out of hand any attempts to insert duplicate data. No need to do a prior check before inserting.
Here is a very basic demo of what happens when you set your table up with this unique constraint, and then try and insert duplicate data. In short: it errors.

Answer 2

$query = $db->query( // query your table );
$array = array('name'=>$_POST['name'],
'address'=>$_POST['address']);
while ($row = mysqli_fetch_all($query)) {
$diff = in_array($array, $row);
{
if(empty($diff))
{
// insert data into table
}
else{
//data already exist
}
}
}

Answer 3

// first check existing recors on the database
$select = "SELECT `Tempat`, `Masa_Mula`, `Masa_Akhir`
FROM `tempahan`
WHERE `Tempat` = {$_POST['tempat']}
AND `Masa_Mula` = {$_POST['masa1']}
AND `Masa_Akhir` = {$_POST['masa2']}";
$result = mysql_query($select, $dbconnection);
// check if the have existing records
// the query fetching depends on your work
// but this is a simple way only
// but have more examples on the internet
// to make query more better and ellegant
if (mysql_num_rows($select) > 0) {
echo 'the place already occupied.';
} else {
// insert new record
$sql="INSERT IGNORE INTO tempahan(Nama,Aktiviti,No_HP,Unit,Tempat,Tarikh_Penggunaan,Masa_Mula,Masa_Akhir,Email)
VALUES(
'$_POST[name]',
'$_POST[Aktiviti]',
'$_POST[number]',
'$_POST[unit]',
'$_POST[tempat]',
'$_POST[tarikh]',
'$_POST[masa1]',
'$_POST[masa2]',
'$_POST[email]')";
echo 'the booking was successful.';
}