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PHP Quick Reference Cheat Sheet by

Quick Reference for useful and basic PHP

HTTP Requests

$_GET
Access URL parame­ters.
$_POST
Access POST request body content.
$_SER­VER­['p­hp_­self']
Current php document url.

Built-in Functions

inclu­de(­"­x.p­hp")
Includes the PHP file "­x.p­hp".
echo "­<co­nte­nt>­"
Renders <c­ont­ent­> on the page on load
die( "­mes­sag­e" )
Exits the script, with a message.
isset­($a)
Returns true if $a is not NULL
isset($a, $b)
Returns true if $a and $b is not NULL
print­_r($x)
Prints readable inform­ation of $x
empty­($x)
Checks if $x is empty or false
trim($x)
Removes leading and trailing whites­paces from $x

PHP MS SQL DLL Functions

sqlsr­v_c­onnect
Connect to Microsoft SQL Server db.
sqlsr­v_q­uery
Prepares and executes a query.
sqlsr­v_f­ree­_stmt
Frees resources for the statement.
sqlsr­v_c­lose
Closes the SQL connec­tion.
sqlsr­v_f­etc­h_a­rray
Returns a row as an array.
sqlsr­v_n­ext­_re­sult
Move to the next result of the statement.
sqlsr­v_e­rrors
Returns error and warning inform­ation.

Example Form Loading

<?php
    // Get the parameter: "Fruit" from the URL query string.
    // Eg. https://example.php/?Fruit=Apple

    $Fruit = $GET['Fruit'];
?>
// Render the variable $Fruit in the HTML
<div>
    <?php echo $Fruit; ?>
</div>
Apple

Example SQL Query Insert

<?php
    $Name = "John Doe";
    $Age = 25;

    $db_server = "<server_hostname>"; 
    $db_username = "<database_username>";
    $db_password = "<database_password>";
    $db_database = "<database_name>";
    $connectionInfo = array("Database"=>$db_database, "UID"=>$db_username, "PWD"=>$db_password);
    $conn = sqlsrv_connect($db_server, $connectionInfo);

    $tsql = "INSERT INTO dbo.Customers ( Name, Age ) VALUES";
    // Append more string literals to the variable $tsql to form the full query
    $tsql .= "('".$Name."', '".$Age."')";

    $stmt = sqlsrv_query($conn, $tsql);

    // Free statement and connection resources.
    sqlsrv_free_stmt($stmt);
    sqlsrv_close($conn);
?>
 

Basic Syntax

$variable = value
Creates a variable, can be of any type.
"string litera­l"
A literal string
// comment
Comments will not execute.
"x"."­y­"
Concat­enates "x" and "y", resulting in "xy­"

Flow Control

if (x) {y} else if (a) {b} else {z}
Condit­ional code block, if x is true, run y. Otherwise, if a is true, run b. Otherwise, run z
do {x} while (y)
A do ... while loop. Executes x as long as y is true
while(x) {y}
A while loop. Executes y as long as x is true

Comparison Operators

!$x
Returns true if $x is false
$x == $y
Returns true if $x matches $y in value
$x === $y
Returns true if $x matches $y in value and type
$x != $y
Returns true if $x does not match $y in value
$x !== $y
Returns true if $x does not match $y in value or type
$x <> $y
Same as $x != $y
$x && $y
Returns true if both $x and $y is true
$x || $y
Returns true if either $x or $y is true
$x > $y
Returns true if $x is greater than $y
$x < $y
Returns true if $x is less than $y
$x >= $y
Returns true if $x is greater than or equal to $y
$x <= $y
Returns true if $x is less than or equal to $y

Example Form Submission

<?php
    // Check if the request is a HTTP POST request. If it is, $_POST will not be empty.
    if ($_POST) {
        $Fruit = $_POST['Fruit'];
        // Fruit will have the value from the input element with the property: name="fruit" upon submission.
    }
?>

<form method="post" action="<?=$_SERVER['php_self']?>">
    <input type="text" name="fruit" id="fruit_id" />
    <input type="submit" value="Submit" />
</form>

Example SQL Query Select

<?php
    $db_server = "<server_hostname>";
    $db_username = "<database_username>";
    $db_password = "<database_password>";
    $db_database = "<database_name>";
    $connectionInfo = array("Database"=>$db_database, "UID"=>$db_username, "PWD"=>$db_password);
    $conn = sqlsrv_connect($db_server, $connectionInfo);

    $tsql = "SELECT FirstName, LastName FROM dbo.Customers";
    $stmt = sqlsrv_query($conn, $tsql);

    if( $stmt === false) {
        die( print_r( sqlsrv_errors(), true) );
    }

    while( $row = sqlsrv_fetch_array( $stmt, SQLSRV_FETCH_ASSOC) ) {
          echo $row['LastName'].", ".$row['FirstName']."<br />";
    }

    // Free statement and connection resources.
    sqlsrv_free_stmt($stmt);
    sqlsrv_close($conn);
?>
Doe, John
Sue, Mary
           
 

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