In-depth analysis of PDO::setAttribute in PHP

##PHP Using PDO to connect to the database is a basic operation. After using PDO to connect to the database, what you get is# For ##Statement type objects, we can use the setAttribute() method to set the attributes of the database handle. This article will take you to take a look.

1. First, let’s take a look at the syntax of setAttribute():

PDO::setAttribute    ( int $attribute   , mixed $value   )

$attribute: Provide the specific attribute name of the PDO object
$value: Assign a value to the specified attribute
The return value is a bool value

2. About the attributes of $attribute

PDO::ATTR_CASE: Force column names to the specified case
PDO::ATTR_ERRMODE: Error reporting.

• ##PDO::ATTR_ORACLE_NULLS (available in all drivers, not limited to Oracle): Convert NULL and empty strings.

• PDO::ATTR_STRINGIFY_FETCHES: Convert the value to a string when extracting

• PDO::ATTR_STATEMENT_CLASS: Set the user-provided values ​​derived from PDOStatement statement class. Requires array

• PDO::ATTR_TIMEOUT: Specifies the number of seconds for timeout.

• PDO::ATTR_AUTOCOMMIT Whether to automatically submit each individual statement.

• PDO::ATTR_EMULATE_PREPARES Enables or disables simulation of prepared statements.

• PDO::MYSQL_ATTR_USE_BUFFERED_QUERY (available in MySQL): Use buffered queries.

• PDO::ATTR_DEFAULT_FETCH_MODE: Set the default extraction mode.

3. Take PDO::ATTR_CASE as an example:

<?php
$servername = "localhost";
$username = "root";
$password = "root123456";
$dbname   = "my_database";
$pdo = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
echo "连接成功"."<br>"; 

$pdo->setAttribute(PDO::ATTR_CASE, PDO::CASE_UPPER);
echo $pdo -> getAttribute(PDO::ATTR_CASE);
$pdo->setAttribute(PDO::ATTR_CASE, PDO::CASE_LOWER);
echo $pdo -> getAttribute(PDO::ATTR_CASE);
$pdo->setAttribute(PDO::ATTR_CASE, PDO::CASE_NATURAL);
echo $pdo -> getAttribute(PDO::ATTR_CASE);
?>

输出：  1
        2
        0

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