I have 2 SQLite databases, one downloaded from a server (server.db
), and one used as storage on the client (client.db
). I need to perform various sync queries on the client database, using data from the server database.
For example, I want to delete all rows in the client.db tRole
table, and repopulate with all rows in the server.db tRole
table.
Another example, I want to delete all rows in the client.db tFile
table where the fileID
is not in the server.db tFile
table.
In SQL Server you can just prefix the table with the name of the database. Is there anyway to do this in SQLite using Adobe Air?
All you need is a disk volume you can create as many SQLite databases as you like. A lesser known feature of SQLite is that you can run queries, including joins, across tables from more than one database. The secret sauce is the ATTACH DATABASE command.
Overview. Usually, SQLite allows at most one writer to proceed concurrently. The BEGIN CONCURRENT enhancement allows multiple writers to process write transactions simultanously if the database is in "wal" or "wal2" mode, although the system still serializes COMMIT commands.
In serialized mode, SQLite can be safely used by multiple threads with no restriction.
Connecting to Multiple Databases For instance, some databases require a default database, whereas others do not. Navicat smooths out these differences by providing a consistent Connection dialog for each database type, with only a few minor variations between screens.
I just looked at the AIR SQL API, and there's an attach
method on SQLConnection
it looks exactly what you need.
I haven't tested this, but according to the documentation it should work:
var connection : SQLConnection = new SQLConnection();
connection.open(firstDbFile);
connection.attach(secondDbFile, "otherDb");
var statement : SQLStatement = new SQLStatement();
statement.connection = connection;
statement.text = "INSERT INTO main.myTable SELECT * FROM otherDb.myTable";
statement.execute();
There may be errors in that code snippet, I haven't worked much with the AIR SQL API lately. Notice that the tables of the database opened with open
are available using main.tableName
, any attached database can be given any name at all (otherDb
in the example above).
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