mysqli_stmt::result_metadata

mysqli_stmt_result_metadata

(PHP 5, PHP 7, PHP 8)

mysqli_stmt::result_metadata -- mysqli_stmt_result_metadata — Returns result set metadata from a prepared statement

Опис

Об'єктно-орієнтований стиль

public mysqli_stmt::result_metadata(): mysqli_result|false

Процедурний стиль

mysqli_stmt_result_metadata(mysqli_stmt $statement): mysqli_result|false

If a statement passed to mysqli_prepare() is one that produces a result set, mysqli_stmt_result_metadata() returns the result object that can be used to process the meta information such as total number of fields and individual field information.

This function returns an empty mysqli_result object which can be used to access metadata information from the prepared statement without having to fetch the actual rows of data. There is no need to use this function when using mysqli_stmt_get_result() to retrieve the entire result set from a prepared statement as a result object.

Зауваження:
This result set object can be passed as an argument only to the field-based functions that process result set metadata, such as:

mysqli_num_fields()

mysqli_fetch_field()

mysqli_fetch_field_direct()

mysqli_fetch_fields()

mysqli_field_count()

mysqli_field_seek()

mysqli_field_tell()

mysqli_free_result()

Зауваження: The result set returned by mysqli_stmt_result_metadata() contains only metadata. It does not contain any row results. The rows are obtained by calling mysqli_stmt_get_result() on the statement handle or with mysqli_stmt_fetch().

Параметри

statement: Тільки процедурний стиль: об'єкт mysqli_stmt, якого повертає функція mysqli_stmt_init().

Значення, що повертаються

Returns a result object or false if an error occurred. If the statement does not produce a result set, false is returned as well.

Помилки/виключення

Якщо увімкнені звіти про помилки mysqli (MYSQLI_REPORT_ERROR) і запитана операція не виконалась, буде виведено попередження, але якщо встановлено режим MYSQLI_REPORT_STRICT, буде викинуто виключення mysqli_sql_exception.

Приклади

Приклад #1 Об'єктно-орієнтований стиль

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

$mysqli->query("DROP TABLE IF EXISTS friends");
$mysqli->query("CREATE TABLE friends (id int, name varchar(20))");

$mysqli->query("INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");

$stmt = $mysqli->prepare("SELECT id, name FROM friends");
$stmt->execute();

/* get resultset for metadata */
$result = $stmt->result_metadata();

/* retrieve field information from metadata result set */
$field = $result->fetch_field();

printf("Fieldname: %s\n", $field->name);
?>

Приклад #2 Процедурний стиль

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

mysqli_query($link, "DROP TABLE IF EXISTS friends");
mysqli_query($link, "CREATE TABLE friends (id int, name varchar(20))");

mysqli_query($link, "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");

$stmt = mysqli_prepare($link, "SELECT id, name FROM friends");
mysqli_stmt_execute($stmt);

/* get resultset for metadata */
$result = mysqli_stmt_result_metadata($stmt);

/* retrieve field information from metadata result set */
$field = mysqli_fetch_field($result);

printf("Fieldname: %s\n", $field->name);
?>

Прогляньте також

mysqli_prepare() - Prepares an SQL statement for execution
mysqli_free_result() - Frees the memory associated with a result
mysqli_stmt_get_result() - Gets a result set from a prepared statement as a mysqli_result object