Android 数据库工具类

最新推荐文章于 2024-09-12 22:30:00 发布

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本文介绍了一个用于Android平台的SQLite数据库助手类，该类提供了一系列基本的CRUD操作，包括插入、更新、删除和查询等方法，并实现了SQLiteOpenHelper的onCreate和onUpgrade方法。

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public class UserSqliteHelper extends SQLiteOpenHelper{
	public static String dbName = "Data.db";
	public static int dbVersion = 1;
	private SQLiteDatabase db;
	public UserSqliteHelper(Context context) {
		super(context, dbName, null, dbVersion);
		// TODO Auto-generated constructor stub
		db = getWritableDatabase();
	}
	public void insert(ContentValues cv){
		db.insert("User", null, cv);
	}
	public void update(ContentValues cv,int id) {
		db.update("User", cv, "_id="+id, null);
	}
	public void delete(int id) {
		db.delete("User", "_id="+id, null);
	}
	public ArrayList<User> select(String where) {
		String sql = "select * from User";
		if (where != null) {
			sql += where;
		}
		Cursor cursor = db.rawQuery(sql, null);
		ArrayList<User> list = new ArrayList<User>();
		while(cursor.moveToNext()){
			User user = new User();
			user.id = cursor.getInt(cursor.getColumnIndex("_id"));
			user.name = cursor.getString(cursor.getColumnIndex("name"));
			user.pwd = cursor.getString(cursor.getColumnIndex("pwd"));
			list.add(user);
		}
		cursor.close();
		return list;
	}
	@Override
	public void onCreate(SQLiteDatabase db) {
		// TODO Auto-generated method stub
		db.execSQL("create table if not exists User(_id INTEGER primary key,name varchar(10),pwd varchar(50))");
		
	}
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		// TODO Auto-generated method stub
		if (newVersion>oldVersion) {
			
		}
	}
	public void destory(){
		if (db != null) {
			db.close();
		}
	}
	
}