pg_fetch_assoc
(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
pg_fetch_assoc — 行を連想配列として取得する
説明
pg_fetch_assoc() は、取得した行（レコード）を 保持する連想配列を返します。
pg_fetch_assoc() は、オプションの第 3 パラメータに
PGSQL_ASSOC を指定して pg_fetch_array()
をコールするのと同じです。連想配列のみを返します。もし数値添字の配列が
必要な場合は pg_fetch_row() を使用してください。
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_assoc() 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。
パラメータ
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。
戻り値
連想配列（フィールド名をキーとする）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、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。
変更履歴
| 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
例1 pg_fetch_assoc() の例
<?php
$conn = pg_connect("dbname=publisher");
if (!$conn) {
echo "An error occurred.\n";
exit;
}
$result = pg_query($conn, "SELECT id, author, email FROM authors");
if (!$result) {
echo "An error occurred.\n";
exit;
}
while ($row = pg_fetch_assoc($result)) {
echo $row['id'];
echo $row['author'];
echo $row['email'];
}
?>参考
- pg_fetch_row() - 数値添字の配列として行を得る
- pg_fetch_array() - 行を配列として取得する
- pg_fetch_object() - 行をオブジェクトとして得る
- pg_fetch_result() - 結果インスタンスから値を返す
＋add a note
User Contributed Notes 17 notes
slurppp at hotmail dot fr ¶
12 years ago
Note that all pg_fetch_* function ignoring the original type of the data and always return strings. (for numbers too)
Anonymous ¶
15 years ago
Beware! If your query returns multiple columns with the same names, only the right-most one will be contained in the result array. This can cause problems if you are using a combination of joins:
For example:
<?php
// Let's say that 'pkey' is the primary-key colum for tables a and b (primary keys are never null)
$res = pg_query("Select a.pkey, b.* FROM a LEFT JOIN b using (pkey)");
$data = pg_fetch_assoc($res);
var_dump($data['pkey']) // Is actually b.pkey, may be NULL!
?>
Both tables contain a column named 'pkey'. Now table 'b' is on the optional side of a LEFT JOIN, so b.pkey (implicitly included via 'b.*') may be NULL.
The problem arises when you use pg_fetch_assoc(), there are two columns named 'pkey' but the result array can only contain one value per key -- in this case it will pick the one from table B instead of the one from table A, and since B is on the optional side of the left-join, $data['pkey'] may be NULL. So if you're expecting to retrieve the column from table A, you need to use a different pg_fetch() or rewrite your query to avoid ambiguity.
Luke ¶
19 years ago
Note:
PostgreSQL boolean values set to TRUE are returned as the string "t"
PostgreSQL boolean values set to FALSE are returned as the string "f"
Anonymous ¶
18 years ago
If you request a row that does not exist, it just fails, rather than simply returning false.
ninja (whorl) thinkninja (stop) com ¶
21 years ago
If you are moving between different versions of PHP, this might be handy:
if (!function_exists('pg_fetch_assoc')) {
function pg_fetch_assoc ($result)
{
return @pg_fetch_array($result, NULL, PGSQL_ASSOC);
}
}
artem.eroshin gmail com ¶
4 years ago
Converts 't' and 'f' to PHP Boolean
$result = pg_query($_db, $sql);
while ( $row = pg_fetch_assoc( $result ) )
{
fixBooleans($result, $row);
//some other code
}
function fixBooleans($result, &$row)
{
for ($fld_i = 0; $fld_i < pg_num_fields($result); $fld_i++)
{
$fld_name = pg_field_name($result, $fld_i);
if( pg_field_type($result, $fld_i) == 'bool' )
{
if( $row[ $fld_name ] == 't' )
{
$row[ $fld_name ] = true;
}
elseif($row[ $fld_name ] == 'f')
{
$row[ $fld_name ] = false;
}
}
}
}
huntfalow at yahoo dot com ¶
9 years ago
<html>
<head>
<script>
function waarde(){
var text = document.getElementById("optVakken").value;
document.getElementById("txthidden").value = text;
document.forms["hiddenform"].submit();
}
</script>
<?php
// keuzemenu met alle leerkrachten
function leerkrachten($aName){
include("includes/connect.php");
}
// keuzemenu met alle vakken
function vakken($aID){
include("includes/connect.php");
$SelectVakkenQuery = "SELECT * FROM vakken";
$SelectVakkenResult = $mysqli->query($SelectVakkenQuery);
$Choice = "<select id='$aID' onchange=waarde()><option>Kies een vak</option>";
while($rij2 = $SelectVakkenResult->fetch_assoc()){
$VakID = $rij2['vakid'];
$Vaknaam = $rij2['voluit'];
$Choice .= "<option value='$VakID'>$Vaknaam</option>";
}
$Choice .= "</select>";
return $Choice;
}
?>
<title>Remediëringsoefening</title>
</head>
<body>
<?php
include("includes/connect.php");
// aanmaken van keuzemenus
// eerste keuzemenu
echo vakken("optVakken")."<br><br>";
// tweede keuzemenu
if(!isset($_POST['txthidden'])){
$SelectLeerkrachtenQuery = "SELECT * FROM leerkrachten";
$SelectLeerkrachtResult = $mysqli->query($SelectLeerkrachtenQuery);
$Choice = "<select>";
while($rij=$SelectLeerkrachtResult->fetch_assoc()){
$Voornaam = $rij['voornaam'];
$Naam = $rij['naam'];
$LKID = $rij['leerkrachtid'];
$Volledig = $Voornaam . " " . $Naam;
$Choice .= "<option value='$LKID'>$Volledig</option>";
}
$Choice .= "</select><br><br>";
echo $Choice;
}else{
$vakid = $_POST['txthidden'];
$SelectLeerkrachtenQuery = "SELECT * FROM leerkrachten JOIN leerkrachtpervak ON leerkrachten.leerkrachtid = leerkrachtpervak.leerkrachtid WHERE vakid = '$vakid'";
$SelectLeerkrachtResult = $mysqli->query($SelectLeerkrachtenQuery);
$Choice = "<select>";
while($row3=$SelectLeerkrachtResult->fetch_assoc()){
$Voornaam = $row3['voornaam'];
$Naam = $row3['naam'];
$Volledig = $Voornaam . " " . $Naam;
$Choice .= "<option>$Volledig</option>";
}
$Choice .= "</select><br><br>";
echo $Choice;
}
// onzichtbaar textbox voor JS
echo "<form method='post' id='hiddenform'><input type='hidden' name='txthidden' id='txthidden'></form>";
$mysqli->close();
?>
</body>
</html>
Alexey Loktionov (error at pochta dot ru) ¶
14 years ago
Here is much powerful pg_parse_array() variant, based on FSM: for any dimension Postgres arrays (its string representation must be well-formed), with quotation rules checks, complexity O(N), where N is a length of string representation of Postgres array:
<?php
define('STATE_BEGIN', 1);
define('STATE_INARRAY',2);
define('STATE_OUTARRAY', 3);
define('STATE_INSLASH', 4);
define('STATE_INQUOTES', 5);
function pg_parse_array($value) {
$resultArray = $indexArray = array(); $level = $index = 0;
$ptr = &$resultArray;
for($i = 0; $i < strlen($value); $i++){
switch($level){
case 1:
if($index > 0){
$ptr = & $ptr[sizeof($ptr)];
}
$indexArray[++$index] = & $ptr;
break;
case -1:
$ptr = & $indexArray[--$index];
break;
}
$level = processFSM($value{$i}, $ptr);
}
return $resultArray;
}
function processFSM($chr, &$result){
static $state = STATE_BEGIN, $index = 0;
$level = 0;
switch(true){
case $chr == '{' && in_array($state, array(STATE_BEGIN,STATE_INARRAY,STATE_OUTARRAY), true):
$state = STATE_INARRAY;
$index = 0;
$level = +1;
break;
case $chr == '}' && in_array($state, array(STATE_INARRAY,STATE_OUTARRAY), true):
$state = STATE_OUTARRAY;
$level = -1;
break;
case $chr == '\\' && $state !== STATE_BEGIN:
$state = $state === STATE_INSLASH ? STATE_INQUOTES : STATE_INSLASH;
break;
case $chr == '"' && !in_array($state, array(STATE_BEGIN,STATE_INSLASH), true):
$state = $state === STATE_INQUOTES ? STATE_INARRAY : STATE_INQUOTES;
break;
case $chr == ',' && in_array($state, array(STATE_INARRAY,STATE_OUTARRAY), true):
$index = sizeof($result);
break;
case $state !== STATE_BEGIN:
$state = $state === STATE_INSLASH ? STATE_INQUOTES : $state;
isset($result[$index]) or $result[$index] = '';
$result[$index] .= $chr;
break;
}
return $level;
}
?>
Anonymous ¶
14 years ago
Be aware that if one of your result fields is an array, it will be output as a string using the general format of '{value1,value2, ... }' in accordance with postgres's behavior with SQL arrays.
http://www.postgresql.org/docs/8.4/static/arrays.html#ARRAYS-IO
So, here is a function to convert simple (one-dimensional) SQL arrays to PHP arrays:
<?php
function pg_parse_array($field)
/*
* Converts a simple SQL array field to its PHP equivalent. e.g:
*
* {null} --> Array(null);
* {"null"} --> Array("null");
* {foo,bar} --> Array("foo", "bar");
* {"foo,bar"} --> Array("foo,bar");
* {"Hello \"World\""} --> Array('Hello "World"');
*
*/
{
// NULL fields are always NULL
if (!is_string($field)) return $field;
// Check for curly braces which may indicate an SQL array field
if ($field[0] != '{' or substr($field, -1) != '}') return $field;
$field = trim(substr($field, 1, -1));
$array = Array();
// Break up the string into the following:
// - quoted text that MAY have special chars escaped by a backslash
// - unquoted text that may NOT have special chars
$search = '/(")?+((?(1)(?:\\\\.|[^"])*|[^,]+))(?(1)\\1)/';
preg_match_all($search, $field, $matches, PREG_SET_ORDER);
foreach($matches as $value)
{
if ($value[1])
{
// Quoted element, with backslash used to escape chars
$array[] = preg_replace('#\\\\(.)#', '$1', $value[2]);
}
else
{
// Unquoted element
$value[2] = trim($value[2]);
if (strtolower($value[2]) == 'null') $array[] = null; // NULL
else $array[] = $value[2];
}
}
return $array;
}
// Some tests to demonstrate this function
var_export(pg_parse_array('{null}'); // Output is Array(null);
var_export(pg_parse_array('{foo,bar}'); // Output is Array('foo', 'bar');
var_export(pg_parse_array('{"null"}'); // Output is Array('null');
?>
Anonymous ¶
16 years ago
bytea columns are returned escaped.
you need to call pg-unescape-bytea() on them to get the original binary back.
Anonymous ¶
16 years ago
regarding the optional int parameter
requesting a row number that is not present in the result set is an error. don't do it.
check with pg_num_rows() beforehand, or just use the default behavior which returns the rows in order and false after returning the last row it returns false immediately if no rows were returned.
javier dot vilarroig at gmail dot com ¶
17 years ago
Is worth to know that when you query on multiple tables only the first row with each name is returned.
That is, if you are joining to tables with a column called 'name' you will receive only one field called name in the array and it will correspond to the one on the first table.
Is advisable to allways allias your columns in that stuation.
johniskew ¶
17 years ago
Here is another way to iterate a resultset and display all columns in very little code... might be faster than a foreach
<?php
print '<table>';
while($row=pg_fetch_assoc($rs2)) print '<tr><td>'.join('</td><td>',$row2).'</td></tr>';
print '</table>';
?>
petrus at bmail dot com dot au ¶
19 years ago
$dbconn3 = pg_connect("host=127.0.0.1 port=5432 dbname=blah user=blah password=blah");
$result = pg_query($dbconn3, "SELECT * FROM Packages");
echo "<HTML><HEAD><TITLE>PostgreSQL Test Page</TITLE></HEAD><BODY>";
echo "<TABLE>";
$pkg = pg_fetch_assoc($result);
foreach ($pkg as $value) {
echo "<TR><TD>$value";
echo "</TR></TD>";
}
echo "</TABLE><P>";
echo "This package's full filename is: {$pkg['name']}-{$pkg['version']}{$pkg['extension']}";
echo "</BODY></HTML>";
For generating tables, this works, and personally I prefer foreach() to while loops because there's no danger of accidentally causing an infinite loop...foreach only works for as long as it has something to work with, and then stops. I thought the echo down the bottom might come in handy, too...took me a bit to find that out.
spam at pasher dot org ¶
21 years ago
An important thing to note (as of PHP 4.3.2):
If you are used to using the "extended" comparision operators (=== and !==) to try to make your code easier to follow visually, this function will return NULL if the provided resource handle is invalid (as opposed to false). ie,
$rs = @pg_query('SELECT * FROM fake_table');
while (false !== ($row = @pg_fetch_assoc($rs)))
{
print_r($row);
}
Obviously you should check to see if $rs === false before you start the while loop, but this example is used to illustrate a potential infinite loop problem if $rs IS false.
Brenton Strickler ¶
21 years ago
At a glance, the syntax listed at the top of this page doesn't match the example. The PGSQL_ASSOC flag isn't necessary.
strata_ranger at hotmail dot com ¶
16 years ago
In a bit of follow-up to Luke's note about SQL booleans (this was a painful thing to learn the hard way), a relatively easy workaround is to typecase the boolean columns to integer inside the query, e.g:
<?php
// Assuming 'foo' is a table column of type boolean
$res = pg_query("Select foo as foo1, foo::integer as foo2 from bar");
$data = pg_fetch_assoc($res);
if ($data['foo1']) echo 'foo1 = TRUE'; // Doesn't work as expected (string 't' and string 'f' both evaluate as TRUE)
if ($data['foo2']) echo 'foo2 = TRUE'; // Works as expected (string '0' evaluates as FALSE)
?>