mysqli_result::fetch_field_direct

mysqli_fetch_field_direct

(PHP 5, PHP 7, PHP 8)

mysqli_result::fetch_field_direct -- mysqli_fetch_field_directRecebe metadados para um único campo

Descrição

Estilo orientado a objetos

public mysqli_result::fetch_field_direct(int $index): object|false

Estilo procedural

mysqli_fetch_field_direct(mysqli_result $result, int $index): object|false

Retorna um objeto que contém informação de definição de campo a partir do conjunto de resultados especificado.

Parâmetros

result

Somente no estilo procedural: Um objeto mysqli_result retornado por mysqli_query(), mysqli_store_result(), mysqli_use_result() ou mysqli_stmt_get_result().

index

O número do campo. Este valor deve estar na faixa de 0 a número de campos - 1.

Valor Retornado

Retorna um objeto que contém informação de definição de campo ou false se nenhuma informação de campo para o valor especificado em index estiver disponível.

Propriedades dos objetos
Propriedade Descrição
name O nome da coluna
orgname O nome original da coluna se foi especificado um apelido
table O nome da tabela à qual o campo pertence (se não calculado)
orgtable Nome da tabela original se foi especificado um apelido
def Não utilizado. Sempre uma string vazia
db O nome do banco de dados
catalog Não utilizado. Sempre "def"
max_length A largura máxima do campo para o conjunto de resultados. A partir do PHP 8.1, este valor é sempre 0.
length O comprimento do campo em bytes. Para colunas de strings, o valor do comprimento varia conforme o conjunto de caracteres. Por exemplo, se o conjunto de caracteres for latin1, um conjunto de um byte, o valor de comprimento para uma consulta SELECT 'abc' será 3. Se o conjunto for utf8mb4, um conjunto multi-bytes onde os caracteres podem ter até 4 bytes, o valor de comprimento será 12.
charsetnr O número do conjunto de caracteres do campo.
flags Um inteiro representando bits de opções para o campo.
type O tipo de dados usado para este campo
decimals O número de decimais para campos numéricos, e a precisão em segundos fracionários para campos temporais.

Exemplos

Exemplo #1 Estilo orientado a objetos

<?php
$mysqli
= new mysqli("localhost", "my_user", "my_password", "world");

/* verifica a conexão */
if (mysqli_connect_errno()) {
printf("Conexão falhou: %s\n", mysqli_connect_error());
exit();
}

$query = "SELECT Name, SurfaceArea from Country ORDER BY Name LIMIT 5";

if (
$result = $mysqli->query($query)) {

/* Obtém informação de campo para a coluna 'SurfaceArea' */
$finfo = $result->fetch_field_direct(1);

printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n", $finfo->type);

$result->close();
}

/* fecha a conexão */
$mysqli->close();
?>

Exemplo #2 Estilo procedural

<?php
$link
= mysqli_connect("localhost", "my_user", "my_password", "world");

/* verifica a conexão */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}

$query = "SELECT Name, SurfaceArea from Country ORDER BY Name LIMIT 5";

if (
$result = mysqli_query($link, $query)) {

/* Obtém informação de campo para a coluna 'SurfaceArea' */
$finfo = mysqli_fetch_field_direct($result, 1);

printf("Name: %s\n", $finfo->name);
printf("Table: %s\n", $finfo->table);
printf("max. Len: %d\n", $finfo->max_length);
printf("Flags: %d\n", $finfo->flags);
printf("Type: %d\n", $finfo->type);

mysqli_free_result($result);
}

/* fecha a conexão */
mysqli_close($link);
?>

Os exemplos acima produzirão:

Name:     SurfaceArea
Table:    Country
max. Len: 10
Flags:    32769
Type:     4

Veja Também

add a note

User Contributed Notes 12 notes

up
16
daniel at summit cove dot com
15 years ago
Here's a bigger list of data types. I got this by creating every type I could and calling fetch_fields():

<?php
$mysql_data_type_hash
= array(
1=>'tinyint',
2=>'smallint',
3=>'int',
4=>'float',
5=>'double',
7=>'timestamp',
8=>'bigint',
9=>'mediumint',
10=>'date',
11=>'time',
12=>'datetime',
13=>'year',
16=>'bit',
//252 is currently mapped to all text and blob types (MySQL 5.0.51a)
253=>'varchar',
254=>'char',
246=>'decimal'
);
?>
up
5
ben dot NOSPAM at NOSPAM dot seraphire dot com
11 years ago
This may be obvious, but the constants for the field types are already defined in PHP, and can be found in the documentation at: http://php.net/manual/en/mysqli.constants.php
up
5
cjs at ashdowntech dot com
15 years ago
According to
http://www.redferni.uklinux.net/mysql/MySQL-Protocol.html

Data type values are:

DECIMAL 0 ENUM 247
TINY 1 SET 248
SHORT 2 TINY_BLOB 249
LONG 3 MEDIUM_BLOB 250
FLOAT 4 LONG_BLOB 251
DOUBLE 5 BLOB 252
NULL 6 VAR_STRING 253
TIMESTAMP 7 STRING 254
LONGLONG 8 GEOMETRY 255
INT24 9
DATE 10
TIME 11
DATETIME 12
YEAR 13
NEWDATE 14

Note that this is not tested and does not contain
all the values noted by deluxmozart
up
5
cjs at ashdowntech dot com
15 years ago
According to
dev.mysql.com/sources/doxygen/mysql-5.1/mysql__com_8h-source.html
the flag bits are:

NOT_NULL_FLAG 1 /* Field can't be NULL */
PRI_KEY_FLAG 2 /* Field is part of a primary key */
UNIQUE_KEY_FLAG 4 /* Field is part of a unique key */
MULTIPLE_KEY_FLAG 8 /* Field is part of a key */
BLOB_FLAG 16 /* Field is a blob */
UNSIGNED_FLAG 32 /* Field is unsigned */
ZEROFILL_FLAG 64 /* Field is zerofill */
BINARY_FLAG 128 /* Field is binary */
ENUM_FLAG 256 /* field is an enum */
AUTO_INCREMENT_FLAG 512 /* field is a autoincrement field */
TIMESTAMP_FLAG 1024 /* Field is a timestamp */
up
2
andre at koethur dot de
10 years ago
Here are two methods for converting the 'type' and 'flags' attributes to text for debugging purposes. They both use the predefined MYSQLI_ constants to generate the text.

<?php

public static function h_type2txt($type_id)
{
static
$types;

if (!isset(
$types))
{
$types = array();
$constants = get_defined_constants(true);
foreach (
$constants['mysqli'] as $c => $n) if (preg_match('/^MYSQLI_TYPE_(.*)/', $c, $m)) $types[$n] = $m[1];
}

return
array_key_exists($type_id, $types)? $types[$type_id] : NULL;
}

public static function
h_flags2txt($flags_num)
{
static
$flags;

if (!isset(
$flags))
{
$flags = array();
$constants = get_defined_constants(true);
foreach (
$constants['mysqli'] as $c => $n) if (preg_match('/MYSQLI_(.*)_FLAG$/', $c, $m)) if (!array_key_exists($n, $flags)) $flags[$n] = $m[1];
}

$result = array();
foreach (
$flags as $n => $t) if ($flags_num & $n) $result[] = $t;
return
implode(' ', $result);
}

?>
up
1
gmx dot net at Hoffmann dot P
10 years ago
Warning!
This function is not only more memory consuming than expected but the consumption also depends on the size of the result set. So if you realy only want to get your field_names you might want to append " LIMIT 1" or use mysqli->unbuffered_query() to save yourself from a memory bloat.
up
1
shoresofnowhere at gmail dot com
14 years ago
Beware of the fact that the ->def property NEVER gets filled with the correct default field value, so it's totally USELESS.

This happens NOT for a bug in php (so don't go filling in a bug report), but happens BY DESIGN, since the MySQL C API call doesn't fill in this value, unless you call the mysql_list_fields() function, which Php doesn't.

See here for reference.
http://dev.mysql.com/doc/refman/5.0/en/c-api-datatypes.html

Also, be aware that if you're using a query which contains subqueries, the primary key/autoincrement flags do NOT get passed along, even if the field you're looking at is the primary autoincrement key of the master table:

SELECT * from (SELECT id from areas) AS subareas

and you'll find primary key and autoinc flags off on id field, even if id was the primary autoinc key of areas table.

This also is by design, i think, since it's supposed that if we're using a subquery then the primary key/autoinc stuff might have no sense at all, since in the result set we can compose fileds from many different tables.

Hoping this is useful, bye!
up
0
anatoliy at ukhvanovy dot name
9 years ago
You can find all available data types here:
https://php.net/manual/ru/mysqli.constants.php
(search "MYSQLI_TYPE_" in your browser)
up
-1
Anonymous
3 years ago
JSON type is 245 if anyone is wondering.
up
-1
bl at example dot com
13 years ago
note that
"SELECT <timestamp-field>, ..."
will return the field with type 7 (timestamp) but with content like "2010-07-14 14:35:08". the point being it is a string.

"SELECT <timestamp-field> + 0, ..."
returns a type 5 (double) but while a number, is not seconds since epoch, but a number in MySQL's "YYYYMMDDHHMMSS" format, in this example:
20100714143508

(PHP 5.2.12)
up
-1
deluxmozart at yahoo dot de
15 years ago
Here are some Numbers of Datatypes. I searched for it but i didn't find a list, where the datatypes of the numbers are listed.

so first I can give this:

3 - Int
10 - Date
246 - Decimal
252 - text
253 - VarChar
254 - Boolean
up
-3
gcdreak at example dot com
14 years ago
I wrote a simple class to get info about fields.
Try it!

<?php
class MysqlFieldsInfo implements Iterator
{

private
$result;
private
$position;
private
$row;


function
__construct($result){
$this->result = $result;
$this->position = 0;
$this->rewind(); // W $results wewnętrzny wskaźnik może być przesunięty więc powracamy do początku
}

public function
current(){
return
$this->row;
}

public function
next(){
$this->position++;
$this->row = $this->result->fetch_field();
}

public function
valid(){
return (boolean)
$this->row;
}

public function
key(){
return
$this->position;
}

public function
rewind(){
$this->position = 0;
$this->result->field_seek(0);
$this->next();
}

// This function show data in table
public function export(){

echo
'<table id="db_table_info">';
echo
'<tr>
<th>Name</th>
<th>Orgname</th>
<th>Table</th>
<th>Orgtable</th>
<th>Def</th>
<th>Max_length</th>
<th>Length</th>
<th>Charsetnr</th>
<th>Flags</th>
<th>Type</th>
<th>Decimals</th>
</tr>'
;
while(
$this->valid()){
echo
'<tr>';
printf("\n\t<td>%s</td>\n", $this->current()->name);
printf("\t<td>%s</td>\n", $this->current()->orgname);
printf("\t<td>%s</td>\n", $this->current()->orgtable);
printf("\t<td>%s</td>\n", $this->current()->def);
printf("\t<td>%s</td>\n", $this->current()->max_length);
printf("\t<td>%s</td>\n", $this->current()->length);
printf("\t<td>%s</td>\n", $this->current()->charsetnr);
printf("\t<td>%s</td>\n", $this->current()->flags);
printf("\t<td>%s</td>\n", $this->current()->type);
printf("\t<td>%s</td>\n", $this->current()->decimals);

echo
'</tr>';

$this->next();
}

echo
'</table>';
}
}
?>
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