The column names if you use PGSQL_ASSOC or PGSQL_BOTH are always in lowercase, no matter what the name is in the database or in the query.
(PHP 4, PHP 5, PHP 7, PHP 8)
pg_fetch_array — 行を配列として取得する
pg_fetch_array() は、取得した行(レコード)を 配列で返します。
pg_fetch_array() は拡張版の pg_fetch_row() です。結果配列のフィールド番号に 対応する要素にデータを格納し、それに加えてフィールド名をキーとした 連想配列にも格納します。デフォルトで、両方ともが有効になっています。
注意: この関数は、 NULL フィールドに PHPの
null
値を設定します。
pg_fetch_array() は、 pg_fetch_row() に比べてきわめて遅いというわけでは 「ありません」。そして、きわめて簡単に使用できます。
result
pg_query()、pg_query_params() や (様々な関数がありますが、特に) pg_execute() が返した PgSql\Result クラスのインスタンス。
row
取得する行番号。最初の行は 0 です。省略したり null
を指定したりした場合は、
次の行を取得します。
mode
返される配列のインデックスを制御するオプションの引数です。
mode
は定数で、以下の値を取ることができます。:
PGSQL_ASSOC
, PGSQL_NUM
, PGSQL_BOTH
。
PGSQL_NUM
を使うと、配列のインデックスを数値にした配列を返します。PGSQL_ASSOC
を使うと、連想配列のインデックスを返します。PGSQL_BOTH
を指定すると、数値と連想配列のインデックスを両方含めた形で配列を返します。
0 から始まる数値添字の配列か連想配列(フィールド名をキーとする)、
あるいはその両方を返します。配列の各要素の値は文字列です。
データベースの NULL
値は、null
として返します。
row
が結果の行数より大きい場合や、行が存在しない場合、
そしてそれ以外のエラーが発生した場合は false
を返します。
SELECT 以外のクエリから結果を取得しようとした場合も、false
を返します。
バージョン | 説明 |
---|---|
8.1.0 |
result は、PgSql\Result
クラスのインスタンスを期待するようになりました。
これより前のバージョンでは、リソース を期待していました。
|
例1 pg_fetch_array() の例
<?php
$conn = pg_pconnect("dbname=publisher");
if (!$conn) {
echo "An error occurred.\n";
exit;
}
$result = pg_query($conn, "SELECT author, email FROM authors");
if (!$result) {
echo "An error occurred.\n";
exit;
}
$arr = pg_fetch_array($result, 0, PGSQL_NUM);
echo $arr[0] . " <- Row 1 Author\n";
echo $arr[1] . " <- Row 1 E-mail\n";
// row パラメータはオプションです。result_type を指定
// したい場合は NULL を渡しておきます。pg_fetch_array を続けてコール
// すると、次の行を取得します。
$arr = pg_fetch_array($result, NULL, PGSQL_ASSOC);
echo $arr["author"] . " <- Row 2 Author\n";
echo $arr["email"] . " <- Row 2 E-mail\n";
$arr = pg_fetch_array($result);
echo $arr["author"] . " <- Row 3 Author\n";
echo $arr[1] . " <- Row 3 E-mail\n";
?>
The column names if you use PGSQL_ASSOC or PGSQL_BOTH are always in lowercase, no matter what the name is in the database or in the query.
As of PHP 4.1.0, you can now use code such as the following to iterate through a result set:
$conn = pg_connect("host=localhost dbname=whatever");
$result = pg_exec($conn, "select * from table");
while ($row = pg_fetch_array($result))
{
echo "data: ".$row["data"];
}
Can be a nice little time saver, PHP with MySQL has supported this for a while but I'm glad to see it extended to PostgreSQL...
PGSQL_BOTH is the default, meaning your array size will be doubled.
If you specify this field (result type), include no quotes around it or you won't get any data, not even an error.
Here's my wrapper function:
function SQL_fetch_array($result_ndx, $row, $result_type=PGSQL_ASSOC) {
return pg_fetch_array($result_ndx, $row, $result_type);
In addition to returning "false if there are no more rows", pg_fetch_array will also trigger an E_WARNING. You can temporarily turn that error reporting level off and suck out all your data like so:
<?php
$errRptLvl = error_reporting();
error_reporting($errRptLvl & ~(E_WARNING));
list($i,$j)=array(0,0);
while ($selection[$i++] = $this->fetchArray($j++)); // (fetchArray is a pg_fetch_array wrapper.)
error_reporting($errRptLvl); // Restore error reporting level.
unset($selection[$i-1]); // Delete the last, empty row.
return $selection;
?>
Note that when using PGSQL_BOTH, numerically and associatively indexed fields are separate variables and treated as such:
<?php
$res = pg_query("Select 'foo' as bar");
$data = pg_fetch_array($res, 0, PGSQL_BOTH);
var_dump($data);
// Array(2)
// {
// [0] => string(3) "foo"
// ["bar"] => string(3) "foo"
// }
// This won't affect $data['bar']
$data[0] = 'bar';
var_dump($data);
// Array(2)
// {
// [0] => string(3) "bar"
// ["bar"] => string(3) "foo"
// }
?>
If you want to have reference binding between your numeric and associative indexes, you'll have to establish that yourself:
<?php
$result = pg_query("Select 'foo' as bar");
$data = pg_fetch_row($result);
// Establish references between column name/number
$from = $data;
foreach($from as $cx => $value)
{
$key = pg_field_name($result, $cx);
if (is_string($key)) $data[$key] =& $data[$cx];
}
var_dump($data);
// Array(2)
// {
// [0] => &string(3) "foo"
// ["bar"] => &string(3) "foo"
// }
// Note the reference binding between $data[0] and $data['bar']
$data[0] = 'baz';
var_dump($data);
// Array(2)
// {
// [0] => &string(3) "baz"
// ["bar"] => &string(3) "baz"
// }
?>
(Timesaver) Be aware of the fact that keys in array returned by this function are (well, at least as of 4.2.3) of the same case as SQL column names (e.g. if your column name is ID then key name is also ID, not id or Id), and the keys in associative array are CASE SENSITIVE!!! So don't be surprised if you get unexpected results. Double check SQL column names and the key names.
In response to eth0's comment below about SELECT'ing from two tables where the tables have columns with the same names, you can get around this problem like this:
"SELECT table1.foo AS foo1, table2.foo AS foo2 FROM table1, table2"
In the associative array returned, the keys will be "foo1" and "foo2".
Hopefully most people realize this on their own, but the examples below where people tried to get creative with getting numerical or associative (not both) keys in the result are rather pointless. See the pg_fetch_assoc() and pg_fetch_row() for the built in functions that do this automatically. It's generally a better idea to use one of these other functions unless you *need* to access fields by both collumn name *and* index.
Just because it is not really clear how to specify the result type, I poste this message.
I wrote a wrapper function which looks like this:
<?php
function db_fetch_array ($result, $row = NULL, $result_type = PGSQL_ASSOC)
{
$return = @pg_fetch_array ($result, $row, $result_type);
return $return;
}
?>
I think this way it is quite comfortable to get the arrays you want.
Please remember that if you have for example a table Customers with "cust_ID", "name" and "address" and another table Users with "u_ID","name" and "other" and then you SELECT WHERE cust_ID=u_ID then you'll get in the result array ONLY ONE "name" field, precisely the last one resulted from the select!!!
Just remember when you 'or die' to close your table(s) or you may get a confused look from non-internet explorer users.