检查mysql中的表名称

问题描述：

I'm trying to implement a way to keep names, entered in an android app and sent to a server, from being used again. I figured the easiest way to do this is create another table and every time a product is added the name is added to the name table. I'm very new to php so this may seem like a very simple question but how would I go about checking the table to see if name is already on it.

here is what I go so far(most of it was already there just the commented out is my thought process)

<?php
// array for JSON response
$response = array();
// check for required fields
if (isset($_POST['name']) && isset($_POST['longitude']) && isset($_POST['latitude']) && isset($_POST['pavement']) && isset($_POST['traffic']) && isset($_POST['environment'])) {
//if(Name is not already in list of names){
$name = $_POST['name'];
$longitude = $_POST['longitude'];
$latitude = $_POST['latitude'];
$pavement = $_POST['pavement'];
$traffic = $_POST['traffic'];
$environment = $_POST['environment'];

// include db connect class
require_once __DIR__ . '/db_connect.php';

// connecting to db
$db = new DB_CONNECT();

// mysql inserting a new row
$result = mysql_query("INSERT INTO spots(name, longitude, latitude, pavement, traffic,     environment) VALUES('$name', '$longitude', '$latitude', '$pavement', '$traffic', '$environment')");
//add new name to table
//$result2 = mysql_query("INSERT INTO names(name) VALUES('$name')");
// check if row inserted or not
if ($result) {
    // successfully inserted into database
    $response["success"] = 1;
    $response["message"] = "Spot successfully created.";

    // echoing JSON response
    echo json_encode($response);
} else {
    // failed to insert row
    $response["success"] = 0;
    $response["message"] = "Oops! An error occurred.";

    // echoing JSON response
    echo json_encode($response);
}
    /*
    } else {
    // name already taken
    $response["success"] = 0;
    $response["message"] = "Name has already been taken.";

    // echoing JSON response
    echo json_encode($response);
}
    */
  } else {
// required field is missing
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";

// echoing JSON response
echo json_encode($response);
}
?>

Sorry for the simple question but thank you in advance,

Tyler

答

You could do a SELECT query like this:

$query = mysql_query("SELECT * FROM spots WHERE name='$name'");
$count = mysql_num_rows($query);
if($count == 0){
    // name not in database
}
else{
    // name is in database
}

However, this is using mysql_ functions which are deprecated. Please use mysqli_ functions instead.

答

Make name primary key in names table or apply unique constrain and check for duplicate key error after insertion in names table

Or you can first query table to see if name is already there or not

$result3 = mysql_query("SELECT * FROM names WHERE name='$name'");
if(mysql_num_rows($result3) <= 0 )
{
   // name is not in names table
  // now insert in names table
}

检查mysql中的表名称

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