The difference between bindParam and bindValue in PHP

PDOStatement :: bindParam() The function is a built-in function in PHP that is used to bind parameters to a specified variable name. This function binds a variable, passes its value as input, and receives the output value of its associated argument tag, if any.

Syntax:

bool PDOStatement::bindParam
( $parameter, $variable, $data_type, $length, $driver_options )

Parameters: This function accepts five parameters as mentioned above, as described below:

$parameter: It is a parameter identifier for Prepare statements using name placeholders. It is the parameter name of the form: name.

$variable: This parameter is used to save the variable name to be bound to the SQL statement parameter.

$data_type: It is the explicit data type of the parameters using PDO::PARAM_* constants.

$length: This parameter is used to save the length of the data type.

$driver_options: This parameter saves the operations that need to be performed.

Return value: This function returns True when successful and false when failed.

Procedure:

<?php   
  
// 设置PDO连接 
$db = new PDO(&#39;mysql:host=localhost;dbname=phps&#39;,&#39;root&#39;,&#39;&#39;);  
  
// 获得用户名
$username = &#39;phpforphp&#39;; 
     
$stmt = $db->prepare("SELECT * FROM users WHERE user = :username"); 
  
// 使用bindParam函数
$stmt->bindParam(&#39;:username&#39;, $username); 
   
 $username = &#39;g4g&#39;; 
     
 $stmt->execute(); 
?>

Note: The SQL statement will be executed using 'g4g' as the username because: username searches for $username at execution time and the last known value of $username was 'g4g '.

PDOStatement::bindValue() The function is a built-in function in PHP that is used to bind values ​​to parameters. This function binds a value to the corresponding named or question mark placeholder in SQL used for prepared statements.

Syntax:

bool PDOStatement::bindValue( $parameter, $value, $data_type )

Parameters: This function accepts the above three parameters as described below:

$parameter: It is a parameter identifier used to account for prepared statement. It is the parameter name of the form: name.

$value: This parameter is used to save the value of the binding parameter.

$data_type: It is the explicit data type of the parameters using PDO::PARAM_* constants.

Return value: This function returns True when successful and False when failed.

Procedure:

<?php   
  
// 设置PDO连接
$db = new PDO(&#39;mysql:host=localhost;dbname=phps&#39;,&#39;root&#39;,&#39;&#39;);  
  
// 获得用户名
$username = &#39;phpforphp&#39;; 
    
$stmt = $db->prepare("SELECT * FROM users WHERE user = :username"); 
  
// 使用bindValue函数
$stmt->bindValue(&#39;:username&#39;, $username); 
  
$username = &#39;g4g&#39;; 
    
$stmt->execute(); 
?>

Note: The SQL statement will be executed using 'g4g' as the username because the literal value "phpforphp" is bound to: bindValue() function previous username. Further changes to $username will not be reflected in the prepared statement.

The difference between bindParam() and bindValue():

bindParam()

bindParam() function will Parameters are bound to named or question mark placeholders in the SQL statement.

bindParam() function is used to pass variables instead of values.

bindValue()

bindValue() function binds a value to a name or question mark in an SQL statement.

bindValue() function is used to pass values ​​and variables.

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