数据库操作的封装

来源：互联网发布：淘宝店铺音乐生成器编辑：程序博客网时间：2024/04/27 22:26

创建表

private void createTable(SQLiteDatabase db){   //创建表SQL语句   String stu_table="create table usertable(_id integer primary key autoincrement,sname text,snumber text)";   //执行SQL语句   db.execSQL(stu_table);   }

插入一条数据

private boolean insert(SQLiteDatabase db){   //实例化常量值   ContentValues cValue = new ContentValues();   //添加用户名   cValue.put("sname","xiaoming");   //添加密码   cValue.put("snumber","01005");   //调用insert()方法插入数据   db.insert("stu_table",null,cValue);   }

删除数据

private boolean delete(SQLiteDatabase db) {   //删除条件   String whereClause = "id=?";   //删除条件参数   String[] whereArgs = {String.valueOf(2)};   //执行删除   db.delete("stu_table",whereClause,whereArgs);   }

修改数据

private boolean update(SQLiteDatabase db) {   //实例化内容值 ContentValues values = new ContentValues();   //在values中添加内容   values.put("snumber","101003");   //修改条件   String whereClause = "id=?";   //修改添加参数   String[] whereArgs={String.valuesOf(1)};   //修改   db.update("usertable",values,whereClause,whereArgs);   }

查询指定数据

private void queryAll(SQLiteDatabase db){Cursor cur = mysql.rawQuery("SELECT * FROM classes WHERE name = 'aab';", null);     if (cur != null) {       while (cur.moveToNext())     {            address = cur.getString(4);       }       Toast.makeText(TimetableActivity.this, "0", Toast.LENGTH_LONG).show();  }    else{          Toast.makeText(TimetableActivity.this, "1", Toast.LENGTH_LONG).show();     }     cur.close();}

查询数据

private void queryAll(SQLiteDatabase db) {   //查询获得游标   Cursor cursor = db.query ("usertable",null,null,null,null,null,null);   //判断游标是否为空   if(cursor.moveToFirst() {   //遍历游标   for(int i=0;i<cursor.getCount();i++){   cursor.move(i);   //获得ID   int id = cursor.getInt(0);   //获得用户名   String username=cursor.getString(1);   //获得密码   String password=cursor.getString(2);   //输出用户信息 System.out.println(id+":"+sname+":"+snumber);   }   }   }

删除数据

private void drop(SQLiteDatabase db){   //删除表的SQL语句   String sql ="DROP TABLE stu_table";   //执行SQL   db.execSQL(sql);   }

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