Transcript
PDOStatements
by Nikkala Thomsonfor CIT 336, section 04
ArrayTemporary
Associates values with keys
Cannot INSERT, DELETE, or UPDATE
DatabasePermanent
Stored as tables with rows and labeled columns
Can INSERT, DELETE, or UPDATE
fetch() or fetchAll()
Fetches the next qualifying row
(Notice the capital )
Fetches all remaining qualifying rows
Indexed
numeric tag (starting with 0)
$car[0] = ‘Ford’;
Associative
string tag
$car[‘model’] = ‘Mustang’;
Multidimensional
multiple tags (each element is an array) $cars[1][‘color’] = ‘red’;
PDO::FETCH_NUM: returns an array indexed by column number, starting at column 0
PDO::FETCH_ASSOC: returns an array indexed by column name
PDO::FETCH_BOTH (default): returns an array indexed by both column name and number (twice as large)
$fetch_style options include:
fruit
name color
apple green
banana yellow
pear red
<?php$sth = $dbh->prepare("SELECT name, color FROM fruit");$sth->execute();
print("PDO::FETCH_NUM: ");print("Return next row as an array indexed by column number\n");$result = $sth->fetch(PDO::FETCH_NUM);print_r($result);print("\n");
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");
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::FETCH_NUM: Return next row as an array indexed by column number
Array (
[0] => apple
[1] => green
)
PDO::FETCH_ASSOC: Return next row as an array indexed by column name
Array (
[name] => banana
[color] => yellow
)
PDO::FETCH_BOTH: Return next row as an array indexed by both column name and number
Array (
[name] => pear
[0] => pear
[color] => red
[1] => red
)
0 apple
1 green
name banana
color yellow
name pear
0 pear
color red
1 red
Same $fetch_style options as fetch() plus…
PDO::FETCH_COLUMN: Specify which column you want with the $fetch_argument parameter. Returns an array consisting of all values from a single column.
PDO::FETCH_COLUMN|PDO::FETCH_UNIQUE: Returns only unique values of a single column.
PDO::FETCH_COLUMN|PDO::FETCH_GROUP: Returns an associative array grouped by the values of the specified column.
<?php$sth = $dbh->prepare("SELECT name, color FROM fruit");$sth->execute();
/* Fetch all of the remaining rows in the result set */print("Fetch all of the remaining rows in the result set:\n");$result = $sth->fetchAll(PDO::FETCH_ASSOC);print_r($result);?>
Fetch all of the remaining rows in the result set:
Array {
[0] => Array (
[name] => apple
[color] => green
)
[1] => Array (
[name] => banana
[color] => yellow
)
[2] => Array (
[name] => pear
[color] => red
)
)
name apple
color green
name banana
color yellow
name pear
color red
0
1
2
<?php$sth = $dbh->prepare("SELECT name, color FROM fruit");$sth->execute();
/* Fetch all of the values of the first column */$result = $sth->fetchAll(PDO::FETCH_COLUMN, 0);var_dump($result);?>
array(3) {
[0] => string(5) “apple”
[1] => string(6) “banana”
[2] => string(4) “pear”
}
0 apple
1 banana
2 pear
<?php$insert = $dbh-> prepare("INSERT INTO fruit(name, color) VALUES (?, ?)");$insert->execute(array('apple', 'red'));$insert->execute(array('pear', 'yellow'));
$sth = $dbh->prepare("SELECT name, color FROM fruit");$sth->execute();
/* Group values by the first column */var_dump($sth-> fetchAll(PDO::FETCH_COLUMN|PDO::FETCH_GROUP));?>
fruit
name color
apple green
banana yellow
pear red
apple red
pear yellow
array(3) {
[“apple”] =>
array(2) {
[0] => string(5) “green”
[1] => string(3) “red”
}
[“banana] =>
array(1) {
[0] => string(5) “yellow”
}
[“pear”] =>
array(2) {
[0] => string(3) “red”
[1] => string(5) “green”
}
}
apple
banana
pear
0 green
1 red
0 yellow
0 red
1 yellow
fetch() vs fetchAll()
Use $fetch_style to structure the results
Don’t use the default BOTH if you can use NUM or ASSOC
When using fetchAll(), try to retrieve only the data you need to conserve system resources
"PDOStatement::fetch." PHP.net. Web. 10 Feb. 2016.
"PDOStatement::fetchAll." PHP.net. Web. 10 Feb. 2016.
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