小弟刚接触android，求大神讲解下下面的代码，感激不尽,该怎么处理

小弟刚接触android，求大神讲解下下面的代码，感激不尽
import java.util.Date;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DB {
private static final String DATABASE_NAME="notes.db";
private static final int DATABASE_VERSION=1;
private static final String DATABASE_TABLE="notes";


private static final String DATABASE_CREATE=
"create table notes("
+"_id INTEGER PRIMARY KEY,"
+"note TEXT NOT NULL,"
+"created INTEGER"
+");";


private static class DatabaseHelper extends SQLiteOpenHelper{

public DatabaseHelper(Context context) {
super(context,DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
}

@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(DATABASE_CREATE);

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS "+DATABASE_TABLE); onCreate(db);
}

}

private Context mCtx=null;
private DatabaseHelper dbHelper;
private SQLiteDatabase db;

public DB(Context ctx){
this.mCtx=ctx;
}

public DB open() throws SQLException{
dbHelper=new DatabaseHelper(mCtx);
db=dbHelper.getWritableDatabase();
return this;
}
public void close(){
dbHelper.close();
}

public static final String KEY_ROWID="_id";
public static final String KEY_NOTE="note";
public static final String KEY_CREATED="created";

String[] strCols=new String[]{
KEY_ROWID,KEY_NOTE,KEY_CREATED
};

public Cursor getAll(){
return db.query(DATABASE_TABLE,strCols,null,null,null,null,null);
}
  //增加记录
public long create(String Note){
Date now=new Date();
ContentValues args=new ContentValues();
args.put(KEY_NOTE, Note);
args.put(KEY_CREATED, now.getTime());
return db.insert(DATABASE_TABLE,null,args);
}
//删除记录
public boolean delete(long rowId){
return db.delete(DATABASE_TABLE, KEY_ROWID+"="+rowId,null )>0;
}

//查询单条记录
public Cursor get(long rowId) throws SQLException{
Cursor mCursor=db.query(true,
DATABASE_TABLE,
new String[]{KEY_ROWID,KEY_NOTE,KEY_CREATED},
KEY_ROWID+"=" +rowId,
null,null,null,null,null);
if(mCursor!=null){
mCursor.moveToFirst();
}
return mCursor;
}
//更新记录
public boolean update(long rowId,String note){
ContentValues args=new ContentValues();
args.put(KEY_NOTE, note);
return db.update(DATABASE_TABLE, args, KEY_ROWID+"="+rowId, null)>0;
}

}

------解决方案--------------------
SQLite的应用，找本书，前面几页应该都能找到。
------解决方案--------------------

探讨

基本的都看不懂，那就玩不了。