(PHP 5, PHP 7, PHP 8)
mysqli_result::fetch_fields -- mysqli_fetch_fields — Returns an array of objects representing the fields in a result set
面向对象风格
过程化风格
This function serves an identical purpose to the mysqli_fetch_field() function with the single difference that, instead of returning one object at a time for each field, the columns are returned as an array of objects.
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。
Returns an array of objects containing field definition information.
| 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 #1 面向对象风格
<?php
$mysqli = new mysqli("127.0.0.1", "root", "foofoo", "sakila");
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
foreach (array('latin1', 'utf8') as $charset) {
// Set character set, to show its impact on some values (e.g., length in bytes)
$mysqli->set_charset($charset);
$query = "SELECT actor_id, last_name from actor ORDER BY actor_id";
echo "======================\n";
echo "Character Set: $charset\n";
echo "======================\n";
if ($result = $mysqli->query($query)) {
/* Get field information for all columns */
$finfo = $result->fetch_fields();
foreach ($finfo as $val) {
printf("Name: %s\n", $val->name);
printf("Table: %s\n", $val->table);
printf("Max. Len: %d\n", $val->max_length);
printf("Length: %d\n", $val->length);
printf("charsetnr: %d\n", $val->charsetnr);
printf("Flags: %d\n", $val->flags);
printf("Type: %d\n\n", $val->type);
}
$result->free();
}
}
$mysqli->close();
?>示例 #2 过程化风格
<?php
$link = mysqli_connect("127.0.0.1", "my_user", "my_password", "sakila");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
foreach (array('latin1', 'utf8') as $charset) {
// Set character set, to show its impact on some values (e.g., length in bytes)
mysqli_set_charset($link, $charset);
$query = "SELECT actor_id, last_name from actor ORDER BY actor_id";
echo "======================\n";
echo "Character Set: $charset\n";
echo "======================\n";
if ($result = mysqli_query($link, $query)) {
/* Get field information for all columns */
$finfo = mysqli_fetch_fields($result);
foreach ($finfo as $val) {
printf("Name: %s\n", $val->name);
printf("Table: %s\n", $val->table);
printf("Max. Len: %d\n", $val->max_length);
printf("Length: %d\n", $val->length);
printf("charsetnr: %d\n", $val->charsetnr);
printf("Flags: %d\n", $val->flags);
printf("Type: %d\n\n", $val->type);
}
mysqli_free_result($result);
}
}
mysqli_close($link);
?>以上示例会输出：
====================== Character Set: latin1 ====================== Name: actor_id Table: actor Max. Len: 3 Length: 5 charsetnr: 63 Flags: 49699 Type: 2 Name: last_name Table: actor Max. Len: 12 Length: 45 charsetnr: 8 Flags: 20489 Type: 253 ====================== Character Set: utf8 ====================== Name: actor_id Table: actor Max. Len: 3 Length: 5 charsetnr: 63 Flags: 49699 Type: 2 Name: last_name Table: actor Max. Len: 12 Length: 135 charsetnr: 33 Flags: 20489