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PHP : Function Reference : PostgreSQL Functions : pg_field_prtlen

pg_field_prtlen

Returns the printed length (PHP 4 >= 4.2.0, PHP 5)
int pg_field_prtlen ( resource result, int row_number, mixed field_name_or_number )
int pg_field_prtlen ( resource result, mixed field_name_or_number )

Example 1929. 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_prtlen

djmaze@moocms

Or even easier to keep things simple on fetching
SELECT a.attname AS name, t.typname AS type, a.attstorage AS i,
   CASE WHEN a.attlen = -1 THEN a.atttypmod ELSE a.attlen END AS size
   FROM pg_attribute a , pg_class c, pg_type t
   WHERE c.relname = 'moo_members'
   AND a.attrelid = c.oid AND a.atttypid = t.oid and a.attnum > 0 and not a.attisdropped


r dot galovic

mysql_field_len () function and more for postgres ...
problems ...
* pg_field_prtlen ... gives the actual size of the field back (it shows the count of the content allready inside the field - not the possible max-len)
* pg_filed_size ... can't be used for varchar or bpchar fields
...but there is a way to get the real-max-length of a field in postgreSQL via the system tables:
//returns an array with infos of every field in the table (name, type, length, size)
function SQLConstructFieldsInfo($TABLE, $DBCON)
{
$s="SELECT a.attname AS name, t.typname AS type, a.attlen AS size, a.atttypmod AS len, a.attstorage AS i
FROM pg_attribute a , pg_class c, pg_type t
WHERE c.relname = '$TABLE'  
AND a.attrelid = c.oid AND a.atttypid = t.oid";

if ($r = pg_query($DBCON,$s))
{
$i=0;
while ($q = pg_fetch_assoc($r))
{
  $a[$i]["type"]=$q["type"];
  $a[$i]["name"]=$q["name"];
  if($q["len"]<0 && $q["i"]!="x")
  {
  // in case of digits if needed ... (+1 for negative values)
  $a[$i]["len"]=(strlen(pow(2,($q["size"]*8)))+1);
  }
  else
  {
  $a[$i]["len"]=$q["len"];
  }
  $a[$i]["size"]=$q["size"];
$i++;
}
return $a;
}
return null;
}
// usage
$DBCON=pg_connect("host=YOUR-HOST port=YOUR-PORT dbname=YOUR-DB user=YOUR-USER password=YOUR-PASS");
$TABLE="YOUR-TABLENAME";
$RET=SQLConstructFieldsInfo($TABLE, $DBCON);
$j = count($RET);
for ($i=0; $i < $j; $i++)
{
echo "
$i name=".$RET[$i]["name"]." type=".$RET[$i]["type"]." length=".$RET[$i]["len"]." size=".$RET[$i]["size"]." bytes";
}


gregm

If you update the query to this:
$s = "SELECT a.attname AS name, t.typname AS type, a.attlen AS size, a.atttypmod AS len, a.attstorage AS i
  FROM pg_attribute a , pg_class c, pg_type t
  WHERE c.relname = '$TABLE'
  AND a.attrelid = c.oid AND a.atttypid = t.oid and a.attnum > 0 and not a.attisdropped";
You get postgres to filter out the 'postgres' columns and get only your columns back.


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