Android Sqlite数据库操作

      Android中的数据存储方式有:SharedPreferences 首选项,文件,网络,sqllite;

很多时候开发APP时需要缓存数据,其中以SQL为最常用了.  在此记录一下sql的各种方法.

　 创建本地数据库与表时,需要写一个数据库帮助类继承SQLiteOpenHelper类.

public class DbHelper extends SQLiteOpenHelper 

   重写方法onCreate(),onUpgrade();

/**
   * 首次创建数据库时调用 第一次调用后不再调用
   * 
   * */
  @Override
  public void onCreate(SQLiteDatabase sdb) {}
 

/** 此方法用于数据更新表结构 */
  @Override
  public void onUpgrade(SQLiteDatabase sdb, int oldVersion, int newVersion) {
    Log.i(TAG, "更新表结构...");
  }

贴一个使用实例:

/**
 * @category 入库记录
 *
 * */
public class DbPutStorage {
  private static final String TAG = "DbPutStorage";
  
  private DbHelper helper;
  private SQLiteDatabase db;

  private static final String TABLE_NAME = "putStorage";

  private static DbPutStorage dbPutStorage;

  public static DbPutStorage getInstance(Context mContext) {
    if (null == dbPutStorage) {
      dbPutStorage = new DbPutStorage(mContext);
    }
    return dbPutStorage;
  }

  public DbPutStorage(Context mContext) {
    helper = new DbHelper(mContext);
    // 因为getWritableDatabase内部调用了mContext.openOrCreateDatabase(mName, 0,
    // mFactory);
    // 所以要确保context已初始化,我们可以把实例化DBManager的步骤放在Activity的onCreate里
    db = helper.getWritableDatabase();
  }

  /**
   * 添加一条数据
   * 
   * @param status:上传状态(0:未上传,1:已上传),logoNo:订单标识
   * */
  public synchronized void addSingle(String logoNo,String _id, 
      String name, String description, String productCode, String order,
      String price, String originalPrice, double quantiy,int status) {
    db = helper.getWritableDatabase();
    Log.i(TAG, "添加单条数据到临时表");
    ContentValues cv = new ContentValues();
    cv.put("logoNo", logoNo);
    cv.put("pro_id", _id);
    cv.put("name", name);
    cv.put("description", description);
    cv.put("productCode", productCode);
    cv.put("orderNo", order);
    cv.put("price", price);
    cv.put("originalPrice", originalPrice);
    cv.put("quantiy", quantiy);
    cv.put("status", status);
    db.insert(TABLE_NAME, null, cv);
    cv.clear();
  }

  /**
   * 查询所有数据
   * 
   * */
  public Cursor selectAll() {
    db = helper.getWritableDatabase();
    Cursor c = db.query(TABLE_NAME, null, null, null, null, null, null);
    return c;
  }
  
  /**
   * 修改某条数据状态
   * 
   * */
  public void updateStatus(String pro_id){
    db = helper.getWritableDatabase();
    ContentValues cv = new ContentValues();
    cv.put("status", 1);
    String[] args = {String.valueOf(pro_id)};
    db.update(TABLE_NAME, cv, "pro_id=?",args);        
  }

  /**
   * 通过rawQuery实现参数查询
   * 
   * @category 根据商品code查询详情
   * */
  public Cursor queryByCode(String search_context) {
    db = helper.getWritableDatabase();
    String sql = "select * from " + TABLE_NAME + " where productCode=?";
    String[] selectionArgs = new String[] { search_context };
    Cursor cursor = db.rawQuery(sql, selectionArgs);
    Log.i(TAG, "根据商品code(" + search_context + ")查询" + cursor.getCount());
    return cursor;
  }
  
  /**
   * 通过rawQuery实现参数查询
   * 
   * @category 根据时间date查询详情
   * */
  public Cursor queryByDate(String search_context) {
    db = helper.getWritableDatabase();
    String sql = "select * from " + TABLE_NAME + " where date=?";
    String[] selectionArgs = new String[] { search_context };
    Cursor cursor = db.rawQuery(sql, selectionArgs);
    Log.i(TAG, "根据时间date(" + search_context + ")查询" + cursor.getCount());
    return cursor;
  }

  /**
   * 通过rawQuery实现模糊参数查询
   * 
   * @category 根据商品名称查询
   * */
  public Cursor queryName(String search_context) {

    db = helper.getWritableDatabase();
    String sql = "select * from " + TABLE_NAME + " where name like ?";
    String[] selectionArgs = new String[] { "%" + search_context + "%" };
    Cursor cursor = db.rawQuery(sql, selectionArgs);
    // if (cursor.moveToFirst()) {
    // return cursor;
    // }
    Log.i(TAG, "根据商品名称查询" + cursor.getCount());
    return cursor;
  }

  /**
   * 通过rawQuery实现模糊参数查询
   * 
   * @category 根据商品标签查询
   * */
  public Cursor queryTagId(String search_context) {

    db = helper.getWritableDatabase();
    String sql = "select * from " + TABLE_NAME + " where productTag like ?";
    String[] selectionArgs = new String[] { "%" + search_context + "%" };
    Cursor cursor = db.rawQuery(sql, selectionArgs);
    Log.i(TAG, "根据商品标签查询" + cursor.getCount());
    return cursor;
  }

  /**
   * 通过rawQuery实现模糊参数查询
   * 
   * @category 根据商品名称或者商品code模糊查询
   * */
  public Cursor query(String search_context) {
    db = helper.getWritableDatabase();
    String sql = "select * from " + TABLE_NAME
        + " where  name like ? or productCode like ?";
    String[] selectionArgs = new String[] { "%" + search_context + "%",
        "%" + search_context + "%" };
    Cursor cursor = db.rawQuery(sql, selectionArgs);
    Log.i(TAG, "模糊查询" + cursor.getCount());
    return cursor;
  }

  /**
   * 判断该条记录是否已存在
   * 
   * */
  public boolean judgeCode(String code) {
    db = helper.getWritableDatabase();
    Cursor c = db.rawQuery("select * from " + TABLE_NAME
        + " where productCode=?", new String[] { code });
    if (c.moveToFirst()) {
      int i = c.getCount();
      if (i > 0) {
        return true;
      }
    }
    return false;
  }

  /**
   * 删除一条指定数据
   * 
   * */
  public void deleteCodeSingle(String productCode) {
    db = helper.getWritableDatabase();
    String whereClause = "productCode=?";// 删除的条件
    String[] whereArgs = { productCode };// 删除的条件参数
    Log.i(TAG, "删除一条指定数据");
    db.delete(TABLE_NAME, whereClause, whereArgs);// 执行删除
  }
  
  /**
   * 删除状态为已上传的数据
   * 
   * */
  public void deleteStatus(String status){
    db = helper.getWritableDatabase();
    String whereClause = "status=?";// 删除的条件
    String[] whereArgs = { status };// 删除的条件参数
    Log.i(TAG, "删除一条已上传的数据");
    db.delete(TABLE_NAME, whereClause, whereArgs);// 执行删除
  }

  /**
   * 删除全部数据
   * 
   * */
  public void deleteTableData() {
    db = helper.getWritableDatabase();
    String sql = "delete  from " + TABLE_NAME;// 删除操作的SQL语句
    Log.i(TAG, "删除sql所有数据...");
    db.execSQL(sql);// 执行删除操作
  }

  /**
   * close database 关闭数据库
   */
  public void closeDB() {
    db = helper.getWritableDatabase();
    db.close();
  }
}