Question

我有一个现有的数据库，我在sqlite数据库浏览器中创建了包含四个表并将其放在assets文件夹中。现在我想通过代码动态地将更多表添加到此数据库中。如何实现这一目标。

Answer 1

首先，您需要通过创建以下内容来创建数据库：

public class DatabaseHelper extends SQLiteOpenHelper {

        private static final String DATABASE_NAME = "mydatabase.db";
        private static final int DATABASE_VERSION = 1;

        private static final String DATABASE_CREATE = "create table mutable (_id integer primary key autoincrement, field1 text not null, field2 text not null);";

        public DatabaseHelper(Context context) {
                super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        // Method that creates database
        @Override
        public void onCreate(SQLiteDatabase database) {
                database.execSQL(DATABASE_CREATE);
        }
}

感谢您需要创建一个DBAdabter类来操作该数据库中的数据：

public class DbAdapter {
  private Context context;
  private SQLiteDatabase database;
  private DatabaseHelper dbHelper;

  // Database fields
  private static final String DATABASE_TABLE      = "mutable";

  public static final String KEY_ID = "_id";
  public static final String KEY_FIELD1 = "field1";
  public static final String KEY_FIELD2 = "field2";

  public DbAdapter(Context context) {
    this.context = context;
  }

  public DbAdapter open() throws SQLException {
    dbHelper = new DatabaseHelper(context);
    database = dbHelper.getWritableDatabase();
    return this;
  }

  public void close() {
    dbHelper.close();
  }

//Create data to be inserted in db
  private ContentValues createContentValues(String field1, String field2) {
    ContentValues values = new ContentValues();
    values.put( KEY_FIELD1, field1 );
    values.put( KEY_FIELD2, field2 );
   return values;
  }

  //Insert in DB
  public long Insert(String field1, String field2) {
    ContentValues values = createContentValues(field1, field2);
    return database.insertOrThrow(DATABASE_TABLE, null, values);
  }

//OTHER METHODS FOR RETRIEVING DATA ETC
}

android动态地将表添加到资产文件夹中的现有数据库

1 个答案: