SQLite3::query
(PHP 5 >= 5.3.0, PHP 7)
SQLite3::query — Выполняет SQL-запрос
Описание
Выполняет SQL-запрос, возвращает объект SQLite3Result, если запрос возвращает результат.
Список параметров
-
query -
SQL-запрос для выполнения.
Возвращаемые значения
Возвращает объект SQLite3Result, если запрос возвращает результат. В противном случае возвращает TRUE, если запрос выполнен, FALSE - при неудаче.
Примеры
Пример #1 Пример SQLite3::query()
<?php
$db = new SQLite3('mysqlitedb.db');
$results = $db->query('SELECT bar FROM foo');
while ($row = $results->fetchArray()) {
var_dump($row);
}
?>
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Расширения для работы с базами данных
- Расширения для работы с базами данных отдельных производителей
- SQLite3
- Функция SQLite3::busyTimeout() - Sets the busy connection handler
- SQLite3::changes
- Функция SQLite3::close() - Closes the database connection
- Функция SQLite3::__construct() - Instantiates an SQLite3 object and opens an SQLite 3 database
- Функция SQLite3::createAggregate() - Registers a PHP function for use as an SQL aggregate function
- Функция SQLite3::createCollation() - Registers a PHP function for use as an SQL collating function
- Функция SQLite3::createFunction() - Registers a PHP function for use as an SQL scalar function
- SQLite3::enableExceptions
- Функция SQLite3::escapeString() - Returns a string that has been properly escaped
- Функция SQLite3::exec() - Executes a result-less query against a given database
- Функция SQLite3::lastErrorCode() - Returns the numeric result code of the most recent failed SQLite request
- Функция SQLite3::lastErrorMsg() - Returns English text describing the most recent failed SQLite request
- Функция SQLite3::lastInsertRowID() - Returns the row ID of the most recent INSERT into the database
- Функция SQLite3::loadExtension() - Attempts to load an SQLite extension library
- Функция SQLite3::open() - Opens an SQLite database
- SQLite3::openBlob
- Функция SQLite3::prepare() - Подготавливает SQL-запрос для выполнения
- Функция SQLite3::query() - Выполняет SQL-запрос
- Функция SQLite3::querySingle() - Executes a query and returns a single result
- Функция SQLite3::version() - Returns the SQLite3 library version as a string constant and as a number
Коментарии
The recommended way to do a SQLite3 query is to use a statement. For a table creation, a query might be fine (and easier) but for an insert, update or select, you should really use a statement, it's really easier and safer as SQLite will escape your parameters according to their type. SQLite will also use less memory than if you created the whole query by yourself. Example:
<?php
$db = new SQLite3;
$statement = $db->prepare('SELECT * FROM table WHERE id = :id;');
$statement->bindValue(':id', $id);
$result = $statement->execute();
?>
You can also re-use a statement and change its parameters, just do $statement->reset(). Finally don't forget to close a statement when you don't need it anymore as it will free some memory.
Check with SQLite3Result::numColumns() for an empty result before calling SQLite3Result::fetchArray().
In contrast to the documentation SQLite3::query() always returns a SQLite3Result instance, not only for queries returning rows (SELECT, EXPLAIN). Each time SQLite3Result::fetchArray() is called on a result from a result-less query internally the query is executed again, which will most probably break your application.
For a framwork or API it's not possible to know in before whether or not a query will return rows (SQLite3 supports multi-statement queries). Therefore the argument "Don't execute query('CREATE ...')" is not valid.