Jiramot.info » sqlite

AIR Encrypted SQLite Database

admin — Thu, 19 Nov 2009 03:06:01 +0000

import flash.data.*;
import flash.filesystem.File;

private var dbConn:SQLConnection = new SQLConnection();
private var dbStatement:SQLStatement = new SQLStatement();

private function init(): void {
  // create a seed string of your choice
  var mySeed:String = "AIR15IsAGreatProduct";

  // prepare a bytearray variable to hold the encryption key
   var myKey:ByteArray = new ByteArray();

 // create the myKey ByteArray
  var i:int = 0;
  for (var j:int=0; j<16; j++) {
    // use hexToInt function and the seed to create the key
    i = (hexToInt(mySeed.charCodeAt(j))*15) +
hexToInt(mySeed.charCodeAt(j+1));

    // use the writeByte method - Writes byte to the byte stream
    myKey.writeByte(i&0x00FF);
  }
  var dbFile:File =
File.desktopDirectory.resolvePath("Encryptedemployees.db");
  dbStatement.sqlConnection = dbConn;

  //pass the key, myKey, to the open method of the SQLConnection,
dbConn
  dbConn.open(dbFile, SQLMode.CREATE, false, 2048, myKey);
}

private function hexToInt(hex:Number):int {
    return parseInt("0x" + hex);
}

SQLite example for AIR

admin — Thu, 19 Nov 2009 03:04:54 +0000

Here is a very simplistic Flex Builder 3 and AIR example that adds and removes records from a table in a local SQLite database. This is not a fully completed AIR project but this code can probably be reused by anyone wanting to get started with AIR+SQLite. There are a couple of other AIR+SQLite examples out there to check out and don’t forget the documentation on the adobe site.

import flash.data.SQLResult;
import flash.filesystem.File;
import flash.data.SQLStatement;
import flash.data.SQLConnection;
import flash.events.SQLEvent;
import flash.events.SQLErrorEvent;
 
import User;
 
private var exampleDB:SQLConnection;
private var exampleDBFile:File;
private var dbStatement:SQLStatement;
 
[Bindable]
private var userData:Array;
 
private function init():void
{
    initAndOpenDatabase();
}
 
private function initAndOpenDatabase():void
{
    exampleDBFile = new File("app-resource:/ExampleDatabase.db");
    exampleDB = new SQLConnection();
    exampleDB.addEventListener(SQLEvent.OPEN, onExampleDBOpened);
    exampleDB.addEventListener(SQLErrorEvent.ERROR, onExampleDBError);
    exampleDB.open(exampleDBFile);
}
 
private function onExampleDBOpened(event:SQLEvent):void
{
    if (event.type == "open")
    {
        getRecords();
    }
}
 
private function onExampleDBError(event:SQLEvent):void
{
}
 
private function getRecords():void
{
    dbStatement = new SQLStatement();
    dbStatement.itemClass = User;
    dbStatement.sqlConnection = exampleDB;
    var sqlQuery:String = "select * from Users";
    dbStatement.text = sqlQuery;
    dbStatement.addEventListener(SQLEvent.RESULT, onDBStatementSelectResult);
    dbStatement.execute();
}
 
private function onDBStatementSelectResult(event:SQLEvent):void
{
    var result:SQLResult = dbStatement.getResult();
    if (result != null)
    {
        userData = result.data;
    }
}
 
private function onDBStatementInsertResult(event:SQLEvent):void
{
    if (exampleDB.totalChanges &gt;= 1)
    {
        getRecords();
    }
}
 
private function addUserToDatabase(user:User):void
{
    var sqlInsert:String = "insert into Users values('"+user.firstname+"','"+user.lastname+"','"+user.email+"');";
    dbStatement.text = sqlInsert;
    dbStatement.removeEventListener(SQLEvent.RESULT, onDBStatementSelectResult);
    dbStatement.addEventListener(SQLEvent.RESULT, onDBStatementInsertResult);
    dbStatement.execute();
}
 
private function onAddUserButtonClicked(event:MouseEvent):void
{
    var user:User = new User();
    user.firstname = firstNameTextInput.text;
    user.lastname = lastNameTextInput.text;
    user.email = emailTextInput.text;
    addUserToDatabase(user);
}
 
private function onUsersDataGridChanged(event:Event):void
{
}
 
private function onRemoveUserButtonClicked(event:MouseEvent):void
{
    removeUserFromDatabase(usersDataGrid.selectedItem as User);
}
 
private function removeUserFromDatabase(user:User):void
{
    var sqlDelete:String = "delete from Users where firstname='"+
                                  user.firstname+"' and lastname='"+
                                  user.lastname+"' and email='"+user.email+"';";
    trace("sqlDelete="+sqlDelete);
    dbStatement.text = sqlDelete;
    dbStatement.removeEventListener(SQLEvent.RESULT, onDBStatementInsertResult);
    dbStatement.addEventListener(SQLEvent.RESULT, onDBStatementDeleteResult);
    dbStatement.execute();
}
 
private function onDBStatementDeleteResult(event:SQLEvent):void
{
    if (exampleDB.totalChanges &gt;= 1)
    {
        getRecords();
    }
}

Derby vs Sqlite

admin — Wed, 05 Aug 2009 11:06:27 +0000

ตอนแรกก็กะว่าจะลองเองว่า derby กับ sqlite ความเร็วมันต่างกันแค่ไหน อะไรเหมาะสมกว่ากันถ้าจะเขียน java แล้วอยากได้ database เล็กๆ ก็เลยมอง derby และ sqlite เอาไว้ ก็เลยลองไปหาข้อมูล แล้วก็เจอเจ้านี่เข้า

Personally, I think there’s no comparison between Derby and SQLite.
Derby’s an actual database with “all” the bells and whistles, but still
a really compact size. SQLite is an extremely fast database-like system
with a much smaller subset of features and SQL compliance. Plus, if
you’re writing in Java, go with Derby. If you’re writing in C or C++,
give SQLite a run-through.

Off the top of my head, SQLite doesn’t support foreign key constraints,
or use column types (everything is a string, unless it’s an int, which
is actually a string). In the quirks department, I’ve noticed join order
can have a dramatic effect on performance. What’s really nice is that
the whole database is a single file, which makes using it as a save file
in your application really nice. Also, startup times are zero. I think
Derby takes a second or two to startup. Both systems support
transactions. Derby can be used in a multi-user mode, while SQLite is
strictly mono-user.

I know both databases claim to be zero-administration, but I’d say
SQLite more serious about it. I don’t even know how to configure SQLite.
Derby certainly works great without administration, but there are a
whole lot of options you can muck with if you like.

source: http://www.nabble.com/Derby-v-SQLite-td13496423.html