PHP Unconference Europe 2015

mysqli_stmt::result_metadata

mysqli_stmt_result_metadata

(PHP 5)

mysqli_stmt::result_metadata -- mysqli_stmt_result_metadataReturns result set metadata from a prepared statement

Descrierea

Stil obiect-orientat

mysqli_result mysqli_stmt::result_metadata ( void )

Stil procedural

mysqli_result mysqli_stmt_result_metadata ( mysqli_stmt $stmt )

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.

Notă:

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()

Notă:

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().

Parametri

stmt

Numai stilul procedural: Un identificator al declarației întors de mysqli_stmt_init().

Valorile întoarse

Returns a result object or FALSE if an error occurred.

Exemple

Example #1 Stil obiect-orientat

<?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 Stil procedural

<?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);
?>

Vedeți de asemenea

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User Contributed Notes 1 note

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10
potherca at gmail dot com
4 years ago
If result_metadata() returns false but error/errno/sqlstate tells you no error occurred, this means your query is one that does not produce a result set, i.e. an INSERT/UPDATE/DELETE query instead of a SELECT query.

This is stated in the documentation where it says "If a statement passed to mysqli_prepare() is one that produces a result set, mysqli_stmt_result_metadata() returns the result object", but it might not be clear to everyone what this entails exactly.

Hope this helps.
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