SQLite3::open
(PHP 5 >= 5.3.0, PHP 7)
SQLite3::open — Opens an SQLite database
Описание
$filename
[, int $flags = SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE
[, string $encryption_key = null
]] )Opens an SQLite 3 Database. If the build includes encryption, then it will attempt to use the key.
Список параметров
-
filename -
Path to the SQLite database, or :memory: to use in-memory database.
-
flags -
Optional flags used to determine how to open the SQLite database. By default, open uses SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE.
-
SQLITE3_OPEN_READONLY: Open the database for reading only.
-
SQLITE3_OPEN_READWRITE: Open the database for reading and writing.
-
SQLITE3_OPEN_CREATE: Create the database if it does not exist.
-
-
encryption_key -
An optional encryption key used when encrypting and decrypting an SQLite database. If the SQLite encryption module is not installed, this parameter will have no effect.
Возвращаемые значения
Эта функция не возвращает значения после выполнения.
Примеры
Пример #1 SQLite3::open() example
<?php
/**
* Simple example of extending the SQLite3 class and changing the __construct
* parameters, then using the open method to initialize the DB.
*/
class MyDB extends SQLite3
{
function __construct()
{
$this->open('mysqlitedb.db');
}
}
$db = new MyDB();
$db->exec('CREATE TABLE foo (bar STRING)');
$db->exec("INSERT INTO foo (bar) VALUES ('This is a test')");
$result = $db->query('SELECT bar FROM foo');
var_dump($result->fetchArray());
?>
- 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
If you are trying to use the open() method to open multiple database files within the same SQLite3 object (which I could not get to work), here is an alternative way to do so using special SQLite3 syntax additions to the SQL language. This took some investigation on my part, so hopefully the solution I found will help you too.
These are the nice features within SQLite3 that are leveraged:
* The create statement query for a table is stored within a table called "sqlite_master" within the parent database file.
* SQLite3 supports the "insert into...select * from" SQL syntax for doing bulkload-speed inserts into a table - but what if the source and target tables are in separate database files?
* SQLite3 has an "attach [filename] as [reference database name]" which will allow multiple database files to be opened and accessible to the same SQLite3 object.
Assume you have a table called "my_template" in the SQLite3 database file "source.db". You want to make a copy of this table into the database file "target.db" and call the table "working_table".
<?php
//attach the source database file to the bulkload connection object;
$bulkload_connection = new SQLite3("c:/sqlite3_database_files/source.db");
//retrieve the create statement query for the source table;
$sourcetbl_create_statement = $bulkload_connection->querySingle("select sql from sqlite_master where type='table' and name='my_template'");
if ($sourcetbl_create_statement===false) exit($bulkload_connection->lastErrorMsg());
//build the create statement query for the target table;
$targettbl_create_statement = str_replace('CREATE TABLE my_template', 'CREATE TABLE bulkload.working_table', $sourcetbl_create_statement);
//attach the target database file to the bulkload connection object - and reference it as the database called [bulkload];
$result=$bulkload_connection->exec("attach 'c:/sqlite3_database_files/target.db' as bulkload");
if ($result===false) exit($bulkload_connection->lastErrorMsg());
//issue the query to create the target table within the target database file;
$result=$bulkload_connection->exec($targettbl_create_statement);
if ($result===false) exit($bulkload_connection->lastErrorMsg());
//copy the rows from the source table to the target table as quickly as possible;
$result=$bulkload_connection->exec("insert into bulkload.working_table select * from my_template");
if ($result===false) exit($bulkload_connection->lastErrorMsg());
//release the OS file locks on the attached database files;
$bulkload_connection->close();
unset($bulkload_connection);
?>
[Editor's note: see <https://www.sqlite.org/backup.html>]
Just a quick note on not being able to open() two databases together and copy the exact info, say for instance to create a backup db. I searched the net for and answer, none of which served. The comment and solution of attaching seems complicated to me. Eventually I worked out that the same result could be more simply accomplished using the copy() function.
<?php
copy("old.db", "new.db");
?>
Note that the SQLITE3_OPEN_READONLY flag cannot be combined with the SQLITE3_OPEN_CREATE flag. If you combine both of these flags, a rather unhelpful "Unable to open database: out of memory" exception will be thrown.If you plan to have concurrent access to a SQLITE3 database, it is advised to change the default SQLite3::busyTimeout value (set to zero by default). Otherwise, you may get a "database locked" error while writing to the database.
With the timeout set to a non zero value, a write attempt to a locked database will wait for the lock to be released (within the timeout) before sending an error.
Note that the default value was set to 60 seconds on SQLITE2.