07. Mysql Mongodb Mssql

[puddlejumper26]

Target: define a library to manage database, support Mysql, Mongodb, Mssql. Require: function inside Mysql, Mongodb, Mssql should be same, with add, update, delete and get methods.

Interface: to define a regulation, constrain the behavior Generics: to solve the repeat of class, interface and method.

Define Generic Interface

interface DBI<T>{
       add(info:T):boolean;
       update(info:T, id:number): boolean;
       delete(id: number): boolean;
       get(id: number):any[];
}

Define Database

In order to implement a Generic interface, the class needs to be also Generic

class MysqlDb<T> implements DBI<T>{
   add(info:T): boolean {
          throw new Error('');
    }
     update(info:T, id:number): boolean {
          throw new Error('');
    }
     delete(id:number): boolean {
          throw new Error('');
    }
     get(id:number): any[] {
          throw new Error('');
    }
}

class MsSqlDb<T> implements DBI<T>{
   add(info:T): boolean {
          throw new Error('');
    }
     update(info:T, id:number): boolean {
          throw new Error('');
    }
     delete(id:number): boolean {
          throw new Error('');
    }
     get(id:number): any[] {
          throw new Error('');
    }
}

Instance

class User{
   username: string | undefined;
   password: string | undefined;
}

var u = new User();
u.username = 'shawn';
u.userpassword = '123';

var oMssql = new MsSqlDb<User>();
oMssql.add(u);