database----Sqlite

主要思路：
    1.DatabaseHelper 继承sqliteOpenHelper
     2. helper = new DatabaseHelper();  数据库助手的实例
    3. 如果改数据库，先通过数据库助手得到数据库（有可修改权限的） SQLiteDatabase db = mOpenHelper.getWritableDatabase();
       3.1如果查询，SQLiteDatabase db = mOpenHelper.getReadableDatabase();    
     4.使用数据库对象操作数据库：
      db.execSQL(sql); //这个似乎万能，推荐只使用这个 ，下面的是对sql的封装  
     db.delete(TABLE_NAME, " title = 'haiyang'", null);
     Cursor cur = db.query(TABLE_NAME, col, null, null, null, null, null);


注意：SimpleCursorAdapter是和数据库有关的东西，而sqlite数据库所要求的 自动增长的 id  必须是 _id这中形式

//===================常用sql 备忘====================================
    String sql = "CREATE TABLE " + TABLE_NAME + " (" + TITLE
+ " text not null, " + BODY + " text not null " + ");";

String sql1 = "insert into " + TABLE_NAME + " (" + TITLE + ", " + BODY
+ ") values('haiyang', 'android的发展真是迅速啊');";

String tracks_sql = "CREATE TABLE " + TrackDbAdapter.TABLE_NAME + " ("
+ TrackDbAdapter.ID + " INTEGER primary key autoincrement, "
+ TrackDbAdapter.NAME + " text not null, "
+ TrackDbAdapter.DESC + " text ,"
+ TrackDbAdapter.DIST + " LONG ,"
+ TrackDbAdapter.TRACKEDTIME + " LONG ,"
+ TrackDbAdapter.LOCATE_COUNT + " INTEGER, "
+ TrackDbAdapter.CREATED + " text, "
+ TrackDbAdapter.AVGSPEED + " LONG, "
+ TrackDbAdapter.MAXSPEED + " LONG ,"
+ TrackDbAdapter.UPDATED + " text "
+ ");";
Log.i(TAG, tracks_sql);
db.execSQL(tracks_sql);

String locats_sql = "CREATE TABLE " + LocateDbAdapter.TABLE_NAME + " ("
+ LocateDbAdapter.ID + " INTEGER primary key autoincrement, "
+ LocateDbAdapter.TRACKID + " INTEGER not null, "
+ LocateDbAdapter.LON + " DOUBLE ,"
+ LocateDbAdapter.LAT + " DOUBLE ,"
+ LocateDbAdapter.ALT + " DOUBLE ,"
+ LocateDbAdapter.CREATED + " text "
+ ");";
Log.i(TAG, locats_sql);
db.execSQL(locats_sql);


Cursor c = managedQuery(Dairy.DairyColumns.DAIRY_URI,
        PROJECTION, null, null, Dairy.DairyColumns.ORDER);
等效于：
mDiaryCursor = db.query(.....); //查询
startManagingCursor(mDiaryCursor);   //绑定activity和cursor的生命周期
//==================================================================




 
   

  private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {

String sql = "CREATE TABLE " + TABLE_NAME + " (" + TITLE
+ " text not null, " + BODY + " text not null " + ");";
Log.i("haiyang:createDB=", sql);
db.execSQL(sql);

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}