Web студия "GrandView"

Description

Procedural style:

int mysqli_field_count ( mysqli link )

Object oriented style (method):

class mysqli_result {

int field_count ( void )

}

Returns the number of columns for the most recent query on the connection represented by the link parameter. This function can be useful when using the mysqli_store_result() function to determine if the query should have produced a non-empty result set or not without knowing the nature of the query.

Возвращаемые значения

An integer representing the number of fields in a result set

Примеры

Пример 1. Object oriented style

<?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')"); $mysqli->real_query($HTTP_POST_VARS['query']); if ($mysqli->field_count) { /* this was a select/show or describe query */ $result = $mysqli->store_result(); /* process resultset */ $row = $result->fetch_row(); /* free resultset */ $result->close(); } /* close connection */ $mysqli->close(); ?>

Пример 2. Procedural style

<?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')"); mysqli_real_query($link, $HTTP_POST_VARS['query']); if (mysqli_field_count($link)) { /* this was a select/show or describe query */ $result = mysqli_store_result($link); /* process resultset */ $row = mysqli_fetch_row($result); /* free resultset */ mysqli_free_result($result); } /* close connection */ mysqli_close($link); ?>

add a note User Contributed Notes
mysqli_field_count

Typer85 at gmail dot com
02-Jan-2007 08:33


For those interested and to clarify the Manual Entry.



For query statements that are DESIGNED to return a result set of some sort, this function will always return the number of fields in the table that was queried.



I said DESIGNED because the return value has no effect on whether or not the actual query matched any rows or not.



For example, say I have a table that has 2 fields and only 10 rows. I issue the following query:



<?php



// Assume Connection Blah Blah.



mysqli_query( $connObject , "Select * From `table` Where `Id` > 1000");



// Get Number Of Fields.



mysqli_field_count( $connObject );



// Will Return 2 --> The Number of fields in the table!



?>



It is quite clear that the query itself will never return a result set because I asked it to return rows which have an Id over 1000 and there are only 10 rows.



But because the nature of the query itself is to return a result set, the field count is always returned no matter what.



In contrast, if the query does anything that does not return a result set by nature, such as an insert or update, the field count will always be 0.



Hence, you can easily determine the nature of this query dynamically using these return values.



Good Luck,



?>

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