MySQLi_Result
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mysqli_result::fetch_field_direct

mysqli_fetch_field_direct

(PHP 5)

mysqli_result::fetch_field_direct -- mysqli_fetch_field_direct — Fetch meta-data for a single field

说明

面向对象风格

object mysqli_result::fetch_field_direct ( int $fieldnr )

过程化风格

object mysqli_fetch_field_direct ( mysqli_result $result , int $fieldnr )

Returns an object which contains field definition information from the specified result set.

参数

result

仅以过程化样式：由 mysqli_query()，mysqli_store_result() 或 mysqli_use_result() 返回的结果集标识。

fieldnr

The field number. This value must be in the range from 0 to number of fields - 1.

返回值

Returns an object which contains field definition information or FALSE if no field information for specified fieldnr is available.

Object attributes
Attribute Description
name The name of the column
orgname Original column name if an alias was specified
table The name of the table this field belongs to (if not calculated)
orgtable Original table name if an alias was specified
def The default value for this field, represented as a string
max_length The maximum width of the field for the result set.
length The width of the field, as specified in the table definition.
charsetnr The character set number for the field.
flags An integer representing the bit-flags for the field.
type The data type used for this field
decimals The number of decimals used (for integer fields)

范例

Example #1 面向对象风格

<?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();
?>

Example #2 过程化风格

<?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' */
    $finfo = mysqli_fetch_field_direct($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);
}

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

以上例程会输出：

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

参见

MySQLi_Result
在线手册：中文 英文
PHP手册
PHP手册 - N: Fetch meta-data for a single field

用户评论:

bl at example dot com (10-Aug-2010 06:11)

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)

shoresofnowhere at gmail dot com (26-Aug-2009 11:50)

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!

gcdreak at example dot com (18-Aug-2009 11:28)

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 wewn?trzny wska?nik mo?e by? przesuni?ty wi?c powracamy do pocz?tku
                }
               
                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>';
                }
            }
?>

daniel at summit cove dot com (22-Feb-2009 11:36)

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'
);
?>

cjs at ashdowntech dot com (17-Sep-2008 05:52)

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

cjs at ashdowntech dot com (13-Sep-2008 04:00)

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 */

deluxmozart at yahoo dot de (24-Jul-2008 07:05)

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