PHP PDO Fetch (With Detailed Explanation)

A PHP PDO Fetch is a method of the (PDOStatement class) which allows you to fetch results from a set of associated row with an object (PDOStatement).

In this article, we will learn what is PDO Fetch and why it is important to learn and understand. This article is a continuation of the previous topic, MySQL Create Tables In PHP with MySQLi and PDO.

What is PHP PDO fetch?

The PDO fetch is a method that returns an array indexed with the same column name and a 0-indexed number column which returns a set of results.

In addition, the PDO fetch also return true and assigns a set of values in the columns in the result set and set to assign variables that are bound with a method name PDOStatement::bindColumn().

What does fetch () do in PHP?

The mysql_fetch_row() allows to fetches one result set of associated row data with a specified identifier result. This row will return an array and each result column will store into an array offset which starts at (offset 0).

How does PHP PDO fetch data?

In PHP, to fetch data from a set of results you will just need to call the following (fetch) methods.

• The PDOStatement::fetch method allows you to return a (single) row from a result set as an object or array.
• The PDOStatement::fetchAll method allows you to fetchall PDO fetch which returns all the rows from a result set as an object or array.

PHP PDO fetch parameters

What is PDO query in PHP?

A PDO::query() is used to execute and prepare an (SQL statement) into a one call function, which returns a statement as an object PDOStatement.

Is PDO better than MySQLi?

The PDO is better than MySQLi in terms of database support. A PDO supports at least (12) different types of databases, just like MySQLi which only supports MySQL database only.

There are some instances when you have to switch your project to another database. The PDO or prepared statements will make the entire process simpler.

Example program for fetching rows using different fetch styles

<?php
$sth = $dbh->prepare("SELECT name, colour FROM fruit");
$sth->execute();

/* Exercise PDOStatement::fetch styles for PDO fetch class returns*/
print("PDO::FETCH_ASSOC: ");
print("Return next row as an array indexed by column name\n");
$result = $sth->fetch(PDO::FETCH_ASSOC);
print_r($result);
print("\n");

/* pdo fetch ori abs and pdo fetch class returns*/
print("PDO::FETCH_BOTH: ");
print("Return next row as an array indexed by both column name and number\n");
$result = $sth->fetch(PDO::FETCH_BOTH);
print_r($result);
print("\n");

/*pdo attr default fetch mode and pdo fetch column*/
print("PDO::FETCH_LAZY: ");
print("Return next row as an anonymous object with column names as properties\n");
$result = $sth->fetch(PDO::FETCH_LAZY);
print_r($result);
print("\n");

print("PDO::FETCH_OBJ: ");
print("Return next row as an anonymous object with column names as properties\n");
$result = $sth->fetch(PDO::FETCH_OBJ);
print $result->name;
print("\n");
?>

Output:

PDO::FETCH_ASSOC: Return next row as an array indexed by column name
Array
(
    [name] => mulberry
    [colour] => red
)

PDO::FETCH_BOTH: Return next row as an array indexed by both column name and number
Array
(
    [name] => watermelon
    [0] => watermelon
    [colour] => red
    [1] => red
)

PDO::FETCH_LAZY: Return next row as an anonymous object with column names as properties
PDORow Object
(
    [name] => apple
    [colour] => red
)

PDO::FETCH_OBJ: Return next row as an anonymous object with column names as properties
kiwi

Example program for fetching rows with a scrollable cursor

<?php
function readDataForwards($dbh) {
    $sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY BET';
    $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
    $stmt->execute();
    while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_NEXT)) {
        $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n";
        print $data;
    }
}
function readDataBackwards($dbh) {
    $sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY bet';
    $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
    $stmt->execute();
    $row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_LAST);
    do {
        $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n";
        print $data;
    } while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_PRIOR));
}

print "Reading forwards:\n";
readDataForwards($conn);

print "Reading backwards:\n";
readDataBackwards($conn);
?>

Output:

Reading forwards:
21    10    5
16    0     5
19    20    10

Reading backwards:
19    20    10
16    0     5
21    10    5

Related Articles

• PHP Arrays (With Advanced Program Examples)
• How to Connect PHP to MySQL Database using PDO

Summary

This article discussed the PHP PDO Fetch. It also tackles what does fetch () do, how does PHP PDO fetch data, what is PDO query, whether Is PDO better than MySQLi, fetches rows using different fetch styles, and fetches rows with a scrollable cursor.

I hope this lesson has helped you learn a lot. Check out my previous and latest articles for more life-changing tutorials which could help you a lot.