mysqli_result::fetch_field_direct

mysqli_fetch_field_direct

(PHP 5, PHP 7, PHP 8)

mysqli_result::fetch_field_direct -- mysqli_fetch_field_direct — 単一のフィールドのメタデータを取得する

説明

オブジェクト指向型

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

手続き型

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

指定した結果セットから、フィールド定義情報を含むオブジェクトを返します。

パラメータ

result: 手続き型のみ: mysqli_query()、mysqli_store_result()、mysqli_use_result()、mysqli_stmt_get_result() が返す mysqli_result オブジェクト。
index: フィールド番号。この値は 0 から フィールド数 - 1 までの範囲でなければなりません。

戻り値

フィールド定義情報を含むオブジェクトを返します。もし、指定した index のフィールドの情報が取得できない場合は false を返します。

**オブジェクトのプロパティ**
プロパティ	説明
name	カラムの名前。
orgname	エイリアスが指定されている場合の、本来の名前。
table	フィールドが属するテーブルの名前 (演算をしていない場合)。
orgtable	エイリアスが指定されている場合の、本来のテーブル名。
def	未使用。常に空文字列になります。
db	データベースの名前。
catalog	未使用。常に `"def"` になります。
max_length	結果セットにおけるフィールドの最大幅。PHP 8.1 以降では、この値は常に `0` です。
length	テーブルの定義で指定されているフィールド幅 (バイト単位)。文字列型のカラムの場合、値の長さは接続の文字セットによって異なります。たとえば文字セットが `latin1`、つまりシングルバイトの文字セットの場合、クエリ `SELECT 'abc'` の値の長さは3になります。一方で文字セットが `utf8mb4` の場合、つまりマルチバイトの文字セットの場合、文字は4バイトまでの長さをとります。値の長さは12になります。
charsetnr	フィールドの文字セット番号。
flags	フィールドのビットフラグを整数型で表す。
type	フィールドのデータ型。
decimals	数値型のフィールドの場合の桁数。時間フィールドの場合は、秒単位の精度。

例

例1 オブジェクト指向型

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

/* 接続状況をチェックします */
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)) {

    /* カラム 'SurfaceArea' のフィールド情報を取得します */
    $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();
}

/* 接続を閉じます */
$mysqli->close();
?>

例2 手続き型

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

/* 接続状況をチェックします */
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)) {

    /* カラム 'SurfaceArea' のフィールド情報を取得します */
    $finfo = mysqli_fetch_field_direct($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);
}

/* 接続を閉じます */
mysqli_close($link);
?>

上の例の出力は以下となります。

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

参考

mysqli_num_fields() - 結果セットのフィールド数を取得する
mysqli_fetch_field() - 結果セットの次のフィールドを返す
mysqli_fetch_fields() - 結果セットのフィールド情報をオブジェクトの配列で返す

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User Contributed Notes 12 notes

down

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'
);
?>

down

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

down

cjs at ashdowntech dot com ¶

16 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

down

cjs at ashdowntech dot com ¶

16 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 */

down

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);
}

?>

down

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.

down

shoresofnowhere at gmail dot com ¶

15 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!

down

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)

down

-1

Anonymous ¶

4 years ago

JSON type is 245 if anyone is wondering.

down

-1

bl at example dot com ¶

14 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)

down

-1

deluxmozart at yahoo dot de ¶

16 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

down

-3

gcdreak at example dot com ¶

15 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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