SunshinePHP Developer Conference 2015

mysqli_fetch_field_direct

result->fetch_field_direct

(PHP 5)

mysqli_fetch_field_direct -- result->fetch_field_direct Obtem meta dados para um único campo

Descrição

Estilo de procedimento:

mixed mysqli_fetch_field_direct ( object $result , int $fieldnr )

Estilo orientado a objeto (metodo):

mixed fetch_field_direct ( int $fieldnr )

mysqli_fetch_field_direct() retorna um objeto o qual contém informações da definição de um campo do conjunto de resultados especificado. O valor de fieldnr deve estar no intervalo entre 0 e número de campos - 1.

Valores de retorno

Retorna um objeto o qual contém informações das definições de um campo ou FALSE se não houver informações sobre o campo especificado com fieldnr disponíveis.

Atributos do objeto
Atibuto Descrição
name O nome da coluna
orgname Nome original da coluna se foi especificado um alias
table O nome da tabela a qual este campo pertence (se não for calculada)
orgtable Nome da tabela original se foi especificado um alias
def O valor padrão para este campo, representado por uma string
max_length O limite de tamanho para o campo no conjunto de resultados.
flags Um inteiro representando bit-flags para o campo.
type O tipo de dados para este campo
decimals O número de casas decimais usadas (para campos integer)

Exemplo

Exemplo #1 Estilo orientado a objeto

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

/* check connection */
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 $mysqli->query($query)) {

    
/* Get field information for column '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();
}

/* close connection */
$mysqli->close();
?>

Exemplo #2 Estilo de procedimento

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

/* check connection */
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)) {

    
/* Get field information for column 'SurfaceArea' */
    
$finfo mysqli_fetch_field_direct($result1);
 
    
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);
}

/* close connection */
mysqli_close($link);
?>

Os exemplos acima devem produzir a seguinte saída:

Name:     SurfaceArea
Table:    Country
max. Len: 10
Flags:    32769
Type:     4
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User Contributed Notes 10 notes

up
1
ben dot NOSPAM at NOSPAM dot seraphire dot com
1 year 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
1
gmx dot net at Hoffmann dot P
4 months 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
andre at koethur dot de
6 months 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
daniel at summit cove dot com
5 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
1
cjs at ashdowntech dot com
6 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
0
bl at example dot com
4 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
0
shoresofnowhere at gmail dot com
5 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
cjs at ashdowntech dot com
6 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
0
deluxmozart at yahoo dot de
6 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
-1
gcdreak at example dot com
5 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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