pg_field_prtlen

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_field_prtlen — Returns the printed length

Açıklama

function pg_field_prtlen(PgSql\Result $result, string|false|null $row, mixed $field_name_or_number): int
function pg_field_prtlen(PgSql\Result $result, mixed $field_name_or_number): int

pg_field_prtlen() returns the actual printed length (number of characters) of a specific value in a PostgreSQL result. Row numbering starts at 0. This function will return false on an error.

field_name_or_number can be passed either as an int or as a string. If it is passed as an int, PHP recognises it as the field number, otherwise as field name.

See the example given at the pg_field_name() page.

Bilginize:

This function used to be called pg_fieldprtlen().

Bağımsız Değişkenler

result

pg_query(), pg_query_params() veya pg_execute() işlevinden dönen PgSql\Result nesnesi.

row

Row number in result. Rows are numbered from 0 upwards. If omitted, current row is fetched.

Dönen Değerler

The field printed length.

Sürüm Bilgisi

Sürüm: Açıklama
8.4.0 The two argument signature of pg_field_prtlen() (result, field_name_or_number) is now deprecated. Use the three argument signature with row set to null instead.
8.3.0 row is now nullable.
8.1.0 sonuç bağımsız değişkeni artık PgSql\Result nesnesi kabul ediyor, evvelce bir özkaynak kabul ederdi.

Örnekler

Örnek 1 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";
  }
?>

Yukarıdaki örneğin çıktısı:

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

Ayrıca Bakınız

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User Contributed Notes 3 notes

up
1
gregm at gxsnmp dot org
19 years ago
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.
up
0
djmaze@moocms
18 years ago
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
up
0
r dot galovic at r-3 dot at
21 years ago
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; $i++)
{
    echo "<br>$i name=".$RET[$i]["name"]." type=".$RET[$i]["type"]." length=".$RET[$i]["len"]." size=".$RET[$i]["size"]." bytes";
}
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