How to write async C# crud methods for Employee model from Apache Cassandra

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

using Cassandra;

using Cassandra.Mapping;

public class EmployeeRepository

{

    private readonly ISession _session;

    private readonly IMapper _mapper;

    public EmployeeRepository(string connectionString, string keyspace)

    {

        var cluster = Cluster.Builder()

            .AddContactPoint(connectionString)

            .Build();

        _session = cluster.Connect(keyspace);

        var mappingConfig = new MappingConfiguration()

            .Define<EmployeeMapping>();

        _mapper = new Mapper(_session, mappingConfig);

    }

    public async Task<string> CreateEmployeeAsync(Employee employee)

    {

        employee.Id = Guid.NewGuid().ToString();

        await _mapper.InsertAsync(employee);

        return employee.Id;

    }

    public async Task<IEnumerable<Employee>> GetEmployeesAsync()

    {

        var query = new SimpleStatement("SELECT * FROM employees");

        var result = await _mapper.FetchAsync<Employee>(query);

        return result.ToList();

    }

    public async Task<Employee> GetEmployeeByIdAsync(string id)

    {

        var query = new SimpleStatement("SELECT * FROM employees WHERE id = ?", id);

        var result = await _mapper.FetchAsync<Employee>(query);

        return result.FirstOrDefault();

    }

    public async Task<bool> UpdateEmployeeAsync(Employee employee)

    {

        var query = new SimpleStatement("UPDATE employees SET name = ?, email = ? WHERE id = ?",

            employee.Name, employee.Email, employee.Id);

        var result = await _session.ExecuteAsync(query);

        return result.WasApplied;

    }

    public async Task<bool> DeleteEmployeeAsync(string id)

    {

        var query = new SimpleStatement("DELETE FROM employees WHERE id = ?", id);

        var result = await _session.ExecuteAsync(query);

        return result.WasApplied;

    }

}