Fazrin/Single Page Application With .Net Core and Blazor

CREATE TABLE Employee (  
EmployeeID int IDENTITY(1,1) PRIMARY KEY,  
Name varchar(20) NOT NULL ,  
City varchar(20) NOT NULL ,  
Department varchar(20) NOT NULL ,  
Gender varchar(6) NOT NULL  
)    
GO      
      
CREATE TABLE Cities (      
CityID int IDENTITY(1,1) NOT NULL PRIMARY KEY,      
CityName varchar(20) NOT NULL       
)      
GO

INSERT INTO Cities VALUES('New Delhi');  
INSERT INTO Cities VALUES('Mumbai');  
INSERT INTO Cities VALUES('Hyderabad');  
INSERT INTO Cities VALUES('Chennai');  
INSERT INTO Cities VALUES('Bengaluru');

 Install-Package Microsoft.EntityFrameworkCore.SqlServer 

 Install-Package Microsoft.EntityFrameworkCore.Tools 

 Scaffold-DbContext "Your connection string here" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models -Tables Employee, Cities 

 
using Microsoft.EntityFrameworkCore;
using ServerSideSPA.App.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace ServerSideSPA.App.DataAccess
{
    public class EmployeeDataAccessLayer
    {
        myTestDBContext db = new myTestDBContext();

        //To Get all employees details     
        public List<Employee> GetAllEmployees()
        {
            try
            {
                return db.Employee.AsNoTracking().ToList();
            }
            catch
            {
                throw;
            }
        }

        //To Add new employee record       
        public void AddEmployee(Employee employee)
        {
            try
            {
                db.Employee.Add(employee);
                db.SaveChanges();
            }
            catch
            {
                throw;
            }
        }

        //To Update the records of a particluar employee      
        public void UpdateEmployee(Employee employee)
        {
            try
            {
                db.Entry(employee).State = EntityState.Modified;
                db.SaveChanges();
            }
            catch
            {
                throw;
            }
        }

        //Get the details of a particular employee      
        public Employee GetEmployeeData(int id)
        {
            try
            {
                var employee = db.Employee.Find(id);
                db.Entry(employee).State = EntityState.Detached;
                return employee;
            }
            catch
            {
                throw;
            }
        }

        //To Delete the record of a particular employee      
        public void DeleteEmployee(int id)
        {
            try
            {
                Employee emp = db.Employee.Find(id);
                db.Employee.Remove(emp);
                db.SaveChanges();
            }
            catch
            {
                throw;
            }
        }

        // To get the list of Cities
        public List<Cities> GetCityData()
        {
            try
            {
                return db.Cities.ToList();
            }
            catch
            {
                throw;
            }
        }
    }
}

 services.AddSingleton<EmployeeService>();