mysqli_result::fetch_field

mysqli_fetch_field

(PHP 5)

mysqli_result::fetch_field -- mysqli_fetch_field — Returns the next field in the result set

说明

面向对象风格

object mysqli_result::fetch_field ( void )

过程化风格

object mysqli_fetch_field ( mysqli_result $result )

Returns the definition of one column of a result set as an object. Call this function repeatedly to retrieve information about all columns in the 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。

返回值

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

**Object properties**
Property	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	Reserved for default value, currently always ""
db	Database (since PHP 5.3.6)
catalog	The catalog name, always "def" (since PHP 5.3.6)
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 Code LIMIT 5";

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

    /* Get field information for all columns */
    while ($finfo = $result->fetch_field()) {

        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\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 Code LIMIT 5";

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

    /* Get field information for all fields */
    while ($finfo = mysqli_fetch_field($result)) {

        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\n", $finfo->type);
    }
    mysqli_free_result($result);
}

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

以上例程会输出：

Name:     Name
Table:    Country
max. Len: 11
Flags:    1
Type:     254

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

参见

mysqli_num_fields() - Get the number of fields in a result
mysqli_fetch_field_direct() - Fetch meta-data for a single field
mysqli_fetch_fields() - Returns an array of objects representing the fields in a result set
mysqli_field_seek() - Set result pointer to a specified field offset

用户评论:

miqrogroove at gmail dot com (2013-01-20 20:19:31)

Beware the values of the predefined constants. They do not always correlate with the actual field types. For example: MYSQLI_TYPE_BLOB: 252 MYSQLI_TYPE_TINY_BLOB: 249 MYSQLI_TYPE_MEDIUM_BLOB: 250 MYSQLI_TYPE_LONG_BLOB: 251 MySQLi will indeed return a value of 252 for a tinytext field, but as you can see, this does not correspond to the value of MYSQLI_TYPE_TINY_BLOB.

Anonymous (2012-02-16 20:20:11)

The constants for the TYPE number returned by fetch_field are enumerated here (MYSQLI_TYPE_*): http://php.net/manual/en/mysqli.constants.php

iansoko at hotmail dot com (2011-10-06 20:24:08)

here are the data types that correspond to the TYPE number returned by fetch_field. thought i would post this here since i couldn't find the info elsewhere. numerics ------------- BIT: 16 TINYINT: 1 BOOL: 1 SMALLINT: 2 MEDIUMINT: 9 INTEGER: 3 BIGINT: 8 SERIAL: 8 FLOAT: 4 DOUBLE: 5 DECIMAL: 246 NUMERIC: 246 FIXED: 246 dates ------------ DATE: 10 DATETIME: 12 TIMESTAMP: 7 TIME: 11 YEAR: 13 strings & binary ------------ CHAR: 254 VARCHAR: 253 ENUM: 254 SET: 254 BINARY: 254 VARBINARY: 253 TINYBLOB: 252 BLOB: 252 MEDIUMBLOB: 252 TINYTEXT: 252 TEXT: 252 MEDIUMTEXT: 252 LONGTEXT: 252

ragtag at hotmail dot com (2008-09-17 05:16:18)

The flags used by MySql are: NOT_NULL_FLAG = 1 PRI_KEY_FLAG = 2 UNIQUE_KEY_FLAG = 4 BLOB_FLAG = 16 UNSIGNED_FLAG = 32 ZEROFILL_FLAG = 64 BINARY_FLAG = 128 ENUM_FLAG = 256 AUTO_INCREMENT_FLAG = 512 TIMESTAMP_FLAG = 1024 SET_FLAG = 2048 NUM_FLAG = 32768 PART_KEY_FLAG = 16384 GROUP_FLAG = 32768 UNIQUE_FLAG = 65536 To test if a flag is set you can use & like so: <?php $meta = $mysqli_result_object->fetch_field(); if ($meta->flags & 4) { echo 'Unique key flag is set'; } ?>