PHP Function Accessing Database Connection

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走了就别回头了 2021-01-14 09:15

How do I allow a function to access a database connection without using GLOBAL?

config.php

 DEFINE (\'DB_HOSTNAME\', \'hostname\');
 DEFINE (\'DB_DAT         


        
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  • 2021-01-14 09:41

    Either pass the database handle to your function, as @KingCrunch and others have said, or call a function that returns the handle:

    In config.php:

    function get_dbc() {
        $dbc = mysqli_connect(DB_HOSTNAME, DB_USERNAME, DB_PASSWORD, DB_DATABASE);
        if(!$dbc) die("Unable to connect to MySQL: " . mysqli_error($dbc));
        return $dbc;
    }
    

    In functions.php:

    require_once('config.php');
    
    function something()
    {
        $dbc = get_dbc();
        $info = mysqli_query($dbc, "SELECT info FROM text") or die("Error: ".mysqli_error($dbc));
    }
    

    You may wish to look at The mysqli Extension and Persistent Connections for details on how you can prevent the connection from being re-established on each call to get_dbc(). There are alternative approaches to this, such as creating a singleton class for your database connection.

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  • 2021-01-14 09:59

    its so simple just pass your $conn variable into another calling function(instead of making new connection) like

    yourpage.php

    $conn = new mysqli($servername, $username, $password, $dbname);
    someFunction ($conn)//you can add other parameters if you like 
    
    function someFunction ($conn) {
        $result = mysqli_query ($conn, "SELECT * FROM examples);
    }
    

    Note:This is not good practice to always make new connection for database access.so always make connection once and use it every where.(but if your requirement different and require multiples connections then you can make multiples connections)

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  • 2021-01-14 10:00

    There are more ways. You could use classic procedural style:

    function something($dbc)
    

    or anonymous function (if you use PHP5.3):

    $fn = function() using ($dbc)
    
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  • 2021-01-14 10:03

    There are two ways one is by passing arguments and the other by using function closure like @Ondrej said. But I wonder both of these require you to modify the code if that is the case, then I would suggest you to use global keyword.

    You can use global keyword to get the scope of variable $dbc

    Try this..

    function something()
    {
       global $dbc;
       $info = mysqli_query($dbc, "SELECT info FROM text") or die("Error: ".mysqli_error($dbc));
    }
    

    (OR)

    Try this...

    function something()
    {
        $dbc = func_get_arg(0);
         $info = mysqli_query($dbc, "SELECT info FROM text") or die("Error: ".mysqli_error($dbc));
    }
    

    & do this ....

    $query = something($dbc);
    
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  • 2021-01-14 10:06

    Use function parameters

    function something ($dbc) {
      // your db code here
    }
    

    function arguments

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