Php/docs/mysqli-stmt.result-metadata
mysqli_stmt::result_metadata
mysqli_stmt_result_metadata
(PHP 5, PHP 7)
mysqli_stmt::result_metadata -- mysqli_stmt_result_metadata — Returns result set metadata from a prepared statement
说明
面向对象风格
public mysqli_stmt::result_metadata ( ) : mysqli_result
过程化风格
mysqli_stmt_result_metadata
( mysqli_stmt $stmt
) : mysqli_result
If a statement passed to mysqli_prepare() is one that produces a result set, mysqli_stmt_result_metadata() returns the result object that can be used to process the meta information such as total number of fields and individual field information.
Note:
This result set pointer can be passed as an argument to any of the field-based functions that process result set metadata, such as:
The result set structure should be freed when you are done with it, which you can do by passing it to mysqli_free_result()
Note:
The result set returned by mysqli_stmt_result_metadata() contains only metadata. It does not contain any row results. The rows are obtained by using the statement handle with mysqli_stmt_fetch().
返回值
Returns a result object or false if an error occurred.
范例
Example #1 面向对象风格
<?php$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", $field->name);/* close resultset */$result->close();/* close connection */$mysqli->close();?>
Example #2 过程化风格
<?php$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", $field->name);/* close resultset */mysqli_free_result($result);/* close connection */mysqli_close($link);?>
参见
- mysqli_prepare() - 准备执行一个 SQL 语句
- mysqli_free_result() - Frees the memory associated with a result
