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PHP : Function Reference : PostgreSQL Functions : pg_field_name

pg_field_name

Returns the name of a field (PHP 4 >= 4.2.0, PHP 5)
string pg_field_name ( resource result, int field_number )

Example 1927. Getting information about fields

<?php
 $dbconn
= pg_connect("dbname=publisher") or die("Could not connect");

 
$res = pg_query($dbconn, "select * from authors where author = 'Orwell'");
 
$i = pg_num_fields($res);
 for (
$j = 0; $j < $i; $j++) {
     echo
"column $j\n";
     
$fieldname = pg_field_name($res, $j);
     echo
"fieldname: $fieldname\n";
     echo
"printed length: " . pg_field_prtlen($res, $fieldname) . " characters\n";
     echo
"storage length: " . pg_field_size($res, $j) . " bytes\n";
     echo
"field type: " . pg_field_type($res, $j) . " \n\n";
 }
?>

The above example will output:

column 0
fieldname: author
printed length: 6 characters
storage length: -1 bytes
field type: varchar

column 1
fieldname: year
printed length: 4 characters
storage length: 2 bytes
field type: int2

column 2
fieldname: title
printed length: 24 characters
storage length: -1 bytes
field type: varchar

Code Examples / Notes » pg_field_name

ccasal

The pg_fieldname function only returns the unqualified name from the select statement. example:
select c.name, con.name from customer c, contacts con where con.customer_id = c.id;
pg_fieldname will return "name" for both fields instead of c.name and con.name.
This is a PostgreSQL limitation, not a PHP limitation.
if you need different field names you should use :
select c.name as customer_name, con.name as contact_name from customer c, contacts con where con.customer_id = c.id;
then pg_fieldname will return "customer_name" and "contact_name"


12-aug-2004 06:01

In fact you can extract the size of the varchar field, by simply sending the following query:
"select a.atttypmod,a.attrelid from pg_attribute as a, pg_class as c where c.relname='$table' AND a.attrelid=c.oid AND a.attname='$field'"
here is a simple function that does that:
function get_field_size($table, $field, $link) {

$result = pg_query($link, "select a.atttypmod,a.attrelid from pg_attribute as a, pg_class as c where c.relname='$table' AND a.attrelid=c.oid AND a.attname='$field'");

$data = pg_fetch_object($result);

return ($data->atttypmod - 4);

}
returned value is a size of a given field (also varchar)


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