SQLite3::open

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

SQLite3::open — Открыть базу данных SQLite

Описание

public SQLite3::open(string $filename, int $flags = SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE, string $encryptionKey = ""): void

Открывает базу данных SQLite 3. Если сборка включает шифрование, то она будет пробовать использовать ключ.

Список параметров

filename

Путь к БД SQLite или :memory: для использования БД в памяти.

flags

Опциональные флаги используемые для определения, как открывать БД. По умолчанию SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE.

SQLITE3_OPEN_READONLY: Открыть БД только для чтения.
SQLITE3_OPEN_READWRITE: Открыть БД для чтения и записи.
SQLITE3_OPEN_CREATE: Создать БД, если её нет.

encryptionKey

Опциональный ключ, для использования шифрования при работе с БД. Если модуль шифрования не установлен, то данная опция не будет использована.

Возвращаемые значения

Функция не возвращает значения после выполнения.

Примеры

Пример #1 Пример использования SQLite3::open()

<?php
/**
 * Простой пример расширения класса SQLite3 и изменения параметров конструктора.
 * После чего использование метода open для инициализации БД.
 */
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());
?>

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User Contributed Notes 4 notes

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jtreurniet at example dot com ¶

7 years ago


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.

down

susan at itsasmartsolve dot co dot za ¶

8 years ago


[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");

?>

down

BenWa ¶

6 years ago


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.

down

kbrobst at surveyresearchpartners dot com ¶

14 years ago


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);

?>

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