PHP Velho Oeste 2024

pg_field_size

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

pg_field_size 返回指定字段的内部存储大小

说明

pg_field_size(PgSql\Result $result, int $field): int

pg_field_size() 返回指定 PostgreSQL result 中字段编号的内部存储大小(以字节为单位)。

注意:

本函数以前的名字为 pg_fieldsize()

参数

result

PgSql\Result 实例,由 pg_query()pg_query_params() 或者 pg_execute()(等)返回。

field

字段编号,从 0 开始。

返回值

内部字段存储大小(以字节为单位)。-1 表示可变长度字段。

更新日志

版本 说明
8.1.0 现在 result 参数接受 PgSql\Result 实例,之前接受 resource

示例

示例 #1 获取字段信息

<?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";
}
?>

以上示例会输出:

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 

参见

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User Contributed Notes 3 notes

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0
ij at NOSPAM dot irj dot co dot za
18 years ago
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
up
0
php at tribun dot de
18 years ago
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;
}
up
-3
alex at linuxNOSPAM dot org dot pe
21 years ago
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
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