SQLite3::query()
(PHP 5 >= 5.3.0, PHP 7)
Executes an SQL query
说明
public SQLite3::query(string $query): SQLite3Result
Executes an SQL query, returning an SQLite3Result object. If the query does not yield a result(such as DML statements)the returned SQLite3Result object is not really usable. Use SQLite3::exec() for such queries instead.
参数
- $query
The SQL query to execute.
返回值
Returns an SQLite3Result object,或者在失败时返回FALSE
.
范例
SQLite3::query() example
<?php $db = new SQLite3('mysqlitedb.db'); $results = $db->query('SELECT bar FROM foo'); while ($row = $results->fetchArray()) { var_dump($row); } ?>
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.