PEAR Справочное руководство
Пред.		След.

DB_common::limitQuery()

DB_common::limitQuery() -- Sends a LIMIT query to the database

Synopsis

mixed &limitQuery (string $query, integer $from, integer $count [, mixed $params = array()])

Описание

Executes a SQL query, but fetches only the the specificed count of rows. It is an emulation of the MySQL LIMIT option.

Параметр

string $query: the SQL query
integer $from: the row to start to fetch. Note that 0 returns the first row, 1 returns the second row, etc.
integer $count: the numbers of rows to fetch
mixed $params: array, string or numeric data to be added to the prepared statement. Quantity of items passed must match quantity of placeholders in the prepared statement: meaning 1 placeholder for non-array parameters or 1 placeholder per array element.

Возвращаемое значение

mixed - a new DB_result object for queries that return results (such as SELECT queries), DB_OK for queries that manipulate data (such as INSERT queries) or a DB_Error object on failure

Throws

Таблица 32-1. Возможные значения PEAR_Error

Error code	Error message	Reason	Solution
`DB_ERROR_NODBSELECTED`	no database selected	No database was choosen.	Check the DSN in connect().
every other error code		Database specific error	Check the database related section of PHP-Manual to detect the reason for this error. In the most cases a misformed SQL statment. Ie. using LIMIT in a SQL-Statment for an Oracle database.

Заметка

Эта функция не должна вызываться статически.

Depending on the database you will not really get more speed compared to query(). The advantage of limitQuery() is the deleting of unneeded rows in the resultset, as early as possible. So this can decrease memory usage.

Пример

Пример 32-1. Using limitQuery()

<?php
// Once you have a valid DB object named $db...
$res =& $db->limitQuery('SELECT * FROM foo', 49, 10);

if (PEAR::isError($res)) {
    die($res->getMessage());
}
?>

См. также

query()

Пред.	Начало	След.
DB_common::getRow()	Уровень выше	DB_common::nextId()