How Can I Ensure MySQL Numeric and Integer Columns Are Returned as the Correct Data Type in PHP?

Converting MySQL Numeric and Integer Columns to Integers in PHP

Problem Overview

PHP queries often return all columns as strings, even when dealing with integer or numeric values in MySQL. This can become problematic when handling data with specific format requirements, such as JSON output consumed by multiple services.

Refuting Common Misconceptions

While some sources claim that returning numeric types is not possible, this is not entirely true. The following misconceptions can be dismissed:

• Type Casting: Manually casting values in the code is inefficient and can introduce inconsistencies.
• Loose Typing: PHP's loose typing is not a reliable solution as data may be unintentionally converted to strings.
• Driver Limitations: The MySQL native driver on Linux does not fully support returning numeric types. However, there is a workaround to ensure correct handling.

Solution

The key to solving this issue is to use the mysqlnd driver for PHP. Unlike the native driver, mysqlnd supports returning numeric types for integer (INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT) and double-precision floating-point (DOUBLE) columns.

Installing and Confirming mysqlnd

To verify if you're using mysqlnd, run php -i. If the pdo_mysql section mentions "mysqlnd," the driver is present. Otherwise, follow these steps to install it:

Ubuntu:

1. Remove the old driver: apt-get remove php5-mysql
2. Install mysqlnd: apt-get install php5-mysqlnd
3. Restart Apache: service apache2 restart

Confirm Presence: After installation, php -i should now display the mysqlnd version in the pdo_mysql section.

PDO Settings

Additionally, ensure that the following PDO settings are set correctly:

• PDO::ATTR_EMULATE_PREPARES should be false
• PDO::ATTR_STRINGIFY_FETCHES should be false

Returned Value Types

• FLOAT and DOUBLE columns are returned as PHP floats.
• INTEGER columns are returned as PHP integers.
• DECIMAL and NUMERIC columns are returned as strings.

Example

With mysqlnd and proper PDO settings, you can now query MySQL tables and obtain numeric values in the expected format:

$result = $pdo->query('SELECT * FROM table');
$row = $result->fetch(PDO::FETCH_OBJ);

echo $row->integer_col; // 1 (integer)
echo $row->double_col; // 1.55 (float)
echo $row->decimal_col; // '1.20' (string)

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