如何正确写大CRUD sqlite android应用

Z时代
2024-01-10
分类：问答

我正在写一个应用程序，操纵数据库由3个表组成。我使用模型（Worker模型，特殊模型）和getter和setter从json文件创建了这个数据库。现在我想从这个数据库中获得特定的信息。我已经做到了，但我的代码非常愚蠢。我需要的是改变我的应用程序的架构，但我不知道它应该是什么样子。这是我的方法的例子，他们很漂亮的一周这是我如何将信息添加到数据库。，我喜欢它，我认为这是正确的：如何正确写大CRUD sqlite android应用

public void addWorker(Worker worker){ 
    List<Specialty> specialty; 
    SQLiteDatabase db = this.getWritableDatabase(); 
    ContentValues values = new ContentValues(); 
    //fixind names 
    String f_name = fixName(worker.getF_name()); 
    String l_name = fixName(worker.getL_name()); 
    String birthday = fixDate(worker.getBirthday()); 
    values.put(KEY_F_NAME, f_name); 
    values.put(KEY_L_NAME, l_name); 
    values.put(KEY_BIRTHDAY, birthday); 
    values.put(KEY_AVATR_URL, worker.getAvart_url()); 
    specialty = worker.getSpecialty(); 
    long worker_id = db.insert(TABLE_WORKERS,null,values); 
    //add unique specialty 
    for (Specialty spec: specialty){ 
     createRelations(worker_id, spec.getSpecialty_id()); 
     if (getCount(spec.getSpecialty_id()) == 0){ 
      addSpecialty(spec); 
     } 
    } 
}

这就是我如何利用信息从数据库中：公众的String [] getFullInfo（字符串WORKER_NAME）{ 字符串selectQuery = “巨额QUERY HERE”，其中workers.f_name ？=“; Log.e（LOG_TAG，selectQuery）;

SQLiteDatabase db = this.getReadableDatabase(); 
    Cursor c = db.rawQuery(selectQuery, new String [] {worker_name}); 
    String[] details = new String[5]; 
    c.moveToFirst(); 
    while (c.isAfterLast() == false){ 
     details[0] = c.getString(c.getColumnIndex(KEY_F_NAME)); 
     details[1] = c.getString(c.getColumnIndex(KEY_L_NAME)); 
     details[2] = c.getString(c.getColumnIndex(KEY_BIRTHDAY)); 
     details[3] = c.getString(c.getColumnIndex("age")); 
     details[4] = c.getString(c.getColumnIndex(KEY_SPEC_NAME)); 
     c.moveToNext(); 
    } 
    return details; 
}

这是我的另一个查询，它有不同的返回类型：

public List<Map<String ,String>> getWorkerListBySpec(String spec_name){ 
    String selectQuery = "HUGE QUERY HERE 
      "where specialty.spec_name=?"; 
    Log.e(LOG_TAG, selectQuery); 
    SQLiteDatabase db = this.getReadableDatabase(); 
    Cursor c = db.rawQuery(selectQuery, new String [] {spec_name}); 
    //making list of workers 
    List<Map<String ,String>> data = new ArrayList<Map<String,String>>(); 
    c.moveToFirst(); 
    while (c.isAfterLast() == false){ 
      Map<String,String> datum = new HashMap<String,String>(2); 
      datum.put(KEY_F_NAME, c.getString(c.getColumnIndex(KEY_F_NAME))); 
      datum.put(KEY_L_NAME, c.getString(c.getColumnIndex(KEY_L_NAME))); 
      datum.put(KEY_BIRTHDAY, c.getString(c.getColumnIndex(KEY_BIRTHDAY))); 
      data.add(datum); 
     c.moveToNext(); 
    } 
    return data; 
}

和第三个，它们也有不同的回报类型：

public List<String> getAllSpecs_Names(){ 
    List<String> spec_names = new ArrayList<String>(); 
    String selectQuery = "select * from " + TABLE_SPECIALTY; 
    Log.e(LOG_TAG, selectQuery); 
    SQLiteDatabase db = this.getReadableDatabase(); 
    Cursor c = db.rawQuery(selectQuery, null); 
    if (c.moveToFirst()){ 
     do{ 
      spec_names.add(c.getString(c.getColumnIndex(KEY_SPEC_NAME))); 
     }while (c.moveToNext()); 
    } 
    return spec_names; 
}

我知道，这都是错的。请告诉我，我应该怎么做我的所有疑问。这将是很好的，如果你给我检查应用程序看起来应该像

回答：

，而不是返回一个列表或地图的链接，你应该更好地返回自己的CursorWrapper

，所以你可以可能看起来像这样的：

public WorkerCursor getWorkerListBySpec(String spec_name){ 
    String selectQuery = "HUGE QUERY HERE 
      "where specialty.spec_name=?"; 
    Log.e(LOG_TAG, selectQuery); 
    SQLiteDatabase db = this.getReadableDatabase(); 
    Cursor c = db.rawQuery(selectQuery, new String [] {spec_name}); 
    return new WorkerCursor(cursor); 
} 
public static class WorkerCursor extends CursorWrapper { 
     /** 
     * Creates a cursor wrapper. 
     * 
     * @param cursor The underlying cursor to wrap. 
     */ 
     public WorkerCursor(Cursor cursor) { 
      super(cursor); 
     } 
     public Worker getWorker() { 
      return getWorkerAtCursor(); 
     } 
     public Worker getWorker(int position) { 
      if (moveToPosition(position)) { 
       return getWorkerCursor(); 
      } else { 
       return null; 
      } 
     } 
     private Worker getWorkerAtCursor() { 
      if (isBeforeFirst() || isAfterLast()) { 
       return null; 
      } 
      worker worker = new Worker(); 
      worker.name = c.getString(c.getColumnIndex(KEY_F_NAME)); 
      .... 
      return worker; 
} 
}