'this code is for insert only, my problem is how to prevent duplicate records before inserting [duplicate]

I want to show data input is already exist array

<?php
if(isset($_POST["med_nom"]))
{
 $connect = new PDO("mysql:host=localhost;dbname=dbs", "", "password");
 for($count = 0; $count < count($_POST["med_nom"]); $count++)
 {
  $query = "INSERT INTO medicinetbl (med_dorder, med_id, med_nom, med_qty, med_prc) VALUES (:med_dorder, :med_id, :med_nom, :med_qty, :med_prc)";
  $statement = $connect->prepare($query);
  $statement->execute(
   array(
    ':med_dorder'  => $_POST["med_dorder"][$count],
    ':med_id'  => $_POST["med_id"][$count], 
    ':med_nom'  => $_POST["med_nom"][$count], 
    ':med_qty' => $_POST["med_qty"][$count], 
    ':med_prc'  => $_POST["med_prc"][$count]
   )
  );
 }
 $result = $statement->fetchAll();
 if(isset($result))
 {
  echo 'ok';
 }
}
?>
phpmysqlpdo


Solution 1:[1]

This is how I check for duplicate Row ID's in my table:

# Generate random Row ID
$rid = rand(1000, 9999);

# start query (yours will be different as I have a class created for starting 
# connections with PDO; nonetheless, you should still understand what im doing here)
$query_ridcheck = $db->connect->prepare("SELECT * FROM `table` WHERE rid=:rid");
$query_ridcheck->bindValue(':rid', $rid, PDO::PARAM_STR);
$query_ridcheck->execute();

# if it fetches any data back (while searching for the newly created $rid), 
# then generate another random $rid again and check again. This while loop will
# keep going until it DOESN"T fetch any data back (meaning the random $rid has 
# not been taken already).
while($query_ridcheck->fetch(PDO::FETCH_ASSOC)){
    $rid = rand(1000, 9999);
    $query_ridcheck = $db->connect->prepare("SELECT * FROM `table` WHERE rid=:rid");
    $query_ridcheck->bindValue(':rid', $rid, PDO::PARAM_STR);
    $query_ridcheck->execute();
}

Essentially, you can check for duplicate data before inserting, and choose what todo. I choose to regenerate the data and check again until I got a string/integer that wasn't a duplicate.

After this check, I go onto insert the data into the table using that row ID (since I now know it will not be taken)

Or like @Your_Common_Sense graciously pointed out, instead of repeating code you can also perform the same function like this:

# executes at lease once, then checks if the condition 
# is true; If it is, continue looping until it's false.
do{
    $rid = rand(1000, 9999);
    $query_ridcheck = $db->connect->prepare("SELECT * FROM `table` WHERE rid=:rid");
    $query_ridcheck->bindValue(':rid', $rid, PDO::PARAM_STR);
    $query_ridcheck->execute();
}while($query_ridcheck->fetch(PDO::FETCH_ASSOC));

Solution 2:[2]

You should search into your data for the values you dont want to be repeated, if there is a record with the values, do not insert.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Isaac Batista

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