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pg_field_prtlen

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

pg_field_prtlenReturns the printed length

Descrição

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

Nota:

This function used to be called pg_fieldprtlen().

Parâmetros

result

Uma instância de PgSql\Result, retornada por pg_query(), pg_query_params() ou pg_execute() (entre outras).

row

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

Valor Retornado

The field printed length.

Registro de Alterações

Versão Descrição
8.3.0 row is now nullable.
8.1.0 O parâmetro result agora espera uma instância de PgSql\Result; anteriormente, um resource era esperado.

Exemplos

Exemplo #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";
}
?>

O exemplo acima produzirá:

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

Veja Também

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User Contributed Notes 3 notes

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1
gregm at gxsnmp dot org
17 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
16 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
19 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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