pg_field_size
(PHP 4 >= 4.2.0, PHP 5, PHP 7)
pg_field_size — Возвращает размер поля
Описание
int pg_field_size
( resource
$result
, int $field_number
)
pg_field_size() возвращает объем памяти (в
байтах), занимаемый значением поля результата запроса PostgreSQL
result.
Замечание:
Прежнее название функции: pg_fieldsize().
Список параметров
-
result -
Ресурс результата запроса PostgreSQL, возвращаемый функциями pg_query(), pg_query_params() или pg_execute() (в числе прочих).
-
field_number -
Порядковый номер поля результата запроса, начиная с нуля.
Возвращаемые значения
Требуемый объем памяти (в байтах) для хранения значения поля.
-1 указывает на переменный размер поля. FALSE в случае ошибки.
Примеры
Пример #1 Получение информации о полях выборки
<?php
$dbconn = pg_connect("dbname=publisher") or die("Невозможно соединиться с базой");
$res = pg_query($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";
}
?>
Результат выполнения данного примера:
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
Смотрите также
- pg_field_prtlen() - Возвращает количество печатаемых символов
- pg_field_type() - Возвращает имя типа заданного поля
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Коментарии
How i can extract the struct of a Postgresql Table?
I want to do a dynamic php code, that see the pg table, and print name, type and size of fields
function get_create_syntax( $table )
{
$qry = "
SELECT *
FROM $table
LIMIT 1
";
$res = pg_query( $qry );
$row = pg_fetch_assoc( $res );
$create = "CREATE TABLE $table \n(\n";
$item = array();
for( $i = 0; $i < count( $row ); $i++ )
{
$name = pg_field_name( $res, $i );
$type = pg_field_type( $res, $i );
$size = pg_field_size( $res, $i );
$item[$i] = '"'.$name.'" '.$type;
$qry = "
SELECT a.atttypmod AS size,
a.attnotnull AS notnull
FROM pg_attribute AS a,
pg_class AS c
WHERE c.relname = '$table'
AND a.attrelid = c.oid
AND a.attname = '$name'
";
$res2 = pg_query( $qry );
$out = pg_fetch_object( $res2 );
if( $out -> size != -1 )
{
$item[$i] .= '('.( $out -> size - 4 ).')';
}
if( $out -> notnull == 't' )
$item[$i] .= ' NOT';
$item[$i] .= ' NULL';
}
$create .= implode( ",\n", $item ) ."\n);";
return $create;
}
To view the file structure of a table using a sql query
select pg_class.relname, pg_attribute.attname, pg_type.typname, pg_type.typlen from pg_class, pg_attribute, pg_type where pg_class.relname = 'YOURTABLENAME' and pg_class.oid = pg_attribute.attrelid and pg_type.oid = pg_attribute.atttypid having attnum > 0