pg_fetch_array
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;
}
?>
pg_fetch_assoc
(PHP 4 >= 4.3.0, PHP 5)
pg_fetch_assoc — Retorna uma linha (registro) como uma matriz associativa
Descrição
array pg_fetch_assoc
( resource $result
[, int $row
] )
pg_fetch_assoc() retorna um array associativo que corresponde à linha (registro) recuperado. Retorna FALSE, se não houver mais registros.
pg_fetch_assoc() é equivalente a usar pg_fetch_row() com PGSQL_ASSOC para o terceiro parâmetro. Ela guarda dados em matrizes com chaves associativas (nome do campo). Se você precisar utilizar os índices numéricos use pg_fetch_row().
row é o número da linha (registro) a ser recuperado. A primeira linha é 0.
pg_fetch_assoc() NÃO é significativamente mais lenta que pg_fetch_row(), e ainda fornece uma significativa facilidade de uso.
Exemplo #1 Retornando linhas (registros) no PostgreSQL
<?php
$conn = pg_pconnect("dbname=revista");
if (!$conn) {
echo "Ocorreu um erro.\n";
exit;
}
$result = pg_query($conn, "SELECT * FROM authors");
if (!$result) {
echo "Ocorreu um erro.\n";
exit;
}
while ($row = pg_fetch_assoc($result)) {
echo $row['id'];
echo $row['author'];
echo $row['email'];
}
?>
Veja também pg_fetch_row(), pg_fetch_array(), pg_fetch_object() e pg_fetch_result().
add a note
User Contributed Notes
pg_fetch_assoc
Alexey Loktionov (error at pochta dot ru)
09-Mar-2010 09:54
Anonymous
15-Jan-2010 08:16
Be aware that if one of your result fields is an array, it will be output as a string using the general format of '{value1,value2, ... }' in accordance with postgres's behavior with SQL arrays.
http://www.postgresql.org/docs/8.4/static/arrays.html#ARRAYS-IO
So, here is a function to convert simple (one-dimensional) SQL arrays to PHP arrays:
<?php
function pg_parse_array($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
19-May-2009 02:24
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.
Anonymous
13-Oct-2008 11:18
bytea columns are returned escaped.
you need to call pg-unescape-bytea() on them to get the original binary back.
Anonymous
13-Oct-2008 10:03
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.
strata_ranger at hotmail dot com
26-Aug-2008 09:01
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)
?>
javier dot vilarroig at gmail dot com
02-Oct-2007 03:57
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
01-Mar-2007 02:28
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>';
?>
24-May-2006 06:59
If you request a row that does not exist, it just fails, rather than simply returning false.
Luke
22-Sep-2005 12:34
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"
petrus at bmail dot com dot au
24-Feb-2005 12:22
$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
24-Oct-2003 12:35
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 $rs IS false.
ninja (whorl) thinkninja (stop) com
21-Jun-2003 02:29
If you are moving between different versions of PHP, this might be handy:
if (!function_exists('pg_fetch_assoc')) {
function pg_fetch_assoc ($result)
{
return @pg_fetch_array($result, NULL, PGSQL_ASSOC);
}
}
Brenton Strickler
06-Jan-2003 10:53
At a glance, the syntax listed at the top of this page doesn't match the example. The PGSQL_ASSOC flag isn't necessary.