mysqli_result::fetch_field_direct

mysqli_fetch_field_direct

(PHP 5, PHP 7, PHP 8)

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

说明

面向对象风格

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

过程化风格

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

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()、 mysqli_use_result()、mysqli_stmt_get_result() 返回的 mysqli_result 对象。

index

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 index 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 Unused. Always an empty string
db The name of the database
catalog Unused. Always "def"
max_length The maximum width of the field for the result set. As of PHP 8.1, this value is always 0.
length The width of the field in bytes. For string columns, the length value varies on the connection character set. For example, if the character set is latin1, a single-byte character set, the length value for a SELECT 'abc' query is 3. If the character set is utf8mb4, a multibyte character set in which characters take up to 4 bytes, the length value is 12.
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 for numeric fields, and the fractional seconds precision for temporal fields.

示例

示例 #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();
?>

示例 #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);
?>

以上示例会输出：

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

参见