database controller asp.net-core-webapi multiple-entries

What should I implement to inset multiple Students in database?

In this, I have implemented a .Net Core web API where I have two model classes Student and Department. I have implemented One to One relationship between these two entities. There are two controllers StudentController and DepartmentController. Student model has reference of Department entity and has DepartmentId as foreign key. Each student is assigned to a department. What implementation is required to perform multiple Students entry in database and how to check the same implementation in Postman? How to create endpoint to add multiple students using JSON format without ViewModel?

Student.cs

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Threading.Tasks;

namespace Students.Models
{
    public class Student
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int SId { get; set; }
        [Required]
        [Column(TypeName ="varchar(50)")]
        public string Name { get; set; }
        public int DepartmentId { get; set; }
        public Department Department { get; set; }
    }
}

Department.cs

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Threading.Tasks;

namespace Students.Models
{
    public class Department
    {
        [Key]
        public int Id { get; set; }
        [Required]
        [Column(TypeName = "varchar(20)")]
        public string Dep { get; set; }
    }
}

DepartmentController.cs

using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Students.Models;

namespace Students.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class DepartmentController : ControllerBase
    {
        private readonly StudentContext _context;

        public DepartmentController(StudentContext context)
        {
            _context = context;
        }

        // GET: api/Department
        [HttpGet]
        public async Task<ActionResult<IEnumerable<Department>>> GetDepartments()
        {
            return await _context.Departments.ToListAsync();
        }

        // GET: api/Department/5
        [HttpGet("{id}")]
        public async Task<ActionResult<Department>> GetDepartment(int id)
        {
            var department = await _context.Departments.FindAsync(id);

            if (department == null)
            {
                return NotFound();
            }

            return department;
        }

        // PUT: api/Department/5
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for
        // more details see https://aka.ms/RazorPagesCRUD.
        [HttpPut("{id}")]
        public async Task<IActionResult> PutDepartment(int id, Department department)
        {
            if (id != department.Id)
            {
                return BadRequest();
            }

            _context.Entry(department).State = EntityState.Modified;

            try
            {
                await _context.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!DepartmentExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return Ok();
        }

        // POST: api/Department
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for
        // more details see https://aka.ms/RazorPagesCRUD.
        [HttpPost]
        public async Task<ActionResult<Department>> PostDepartment(Department department)
        {
            _context.Departments.Add(department);
            await _context.SaveChangesAsync();

            return CreatedAtAction("GetDepartment", new { id = department.Id }, department);
        }

        // DELETE: api/Department/5
        [HttpDelete("{id}")]
        public async Task<ActionResult<Department>> DeleteDepartment(int id)
        {
            var department = await _context.Departments.FindAsync(id);
            if (department == null)
            {
                return NotFound();
            }

            _context.Departments.Remove(department);
            await _context.SaveChangesAsync();

            return department;
        }

        private bool DepartmentExists(int id)
        {
            return _context.Departments.Any(e => e.Id == id);
        }
    }
}

StudentsController.cs

using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Students.Models;

namespace Students.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class StudentsController : ControllerBase
    {
        private readonly StudentContext _context;

        public StudentsController(StudentContext context)
        {
            _context = context;
        }

        // GET: api/Students
        [HttpGet]
        public async Task<ActionResult<IEnumerable<Student>>> GetStudents()
        {
            return await _context.Students.Include(d => d.Department).ToListAsync();
        }

        // GET: api/Students/5
        [HttpGet("{id}")]
        public async Task<ActionResult<Student>> GetStudent(int id)
        {
            var student = await _context.Students.Include(d => d.Department).FirstOrDefaultAsync(i => i.SId == id);

            if (student == null)
            {
                return NotFound();
            }

            return student;
        }

        // PUT: api/Students/5
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for
        // more details see https://aka.ms/RazorPagesCRUD.
        [HttpPut("{id}")]
        public async Task<IActionResult> PutStudent(int id, Student student)
        {
            if (id != student.SId)
            {
                return BadRequest();
            }
            _context.Departments.Update(student.Department);
            await _context.SaveChangesAsync();
            _context.Entry(student).State = EntityState.Modified;

            try
            {
                await _context.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!StudentExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return Ok();
        }

        // POST: api/Students
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for
        // more details see https://aka.ms/RazorPagesCRUD.
        [HttpPost]
        public async Task<ActionResult<Student>> PostStudent(Student student)
        {
            //_context.Departments.Add(student.Department);
            //await _context.SaveChangesAsync();
            _context.Students.Add(student);
            await _context.SaveChangesAsync();

            return CreatedAtAction("GetStudent", new { id = student.SId }, student);
        }

        // DELETE: api/Students/5
        [HttpDelete("{id}")]
        public async Task<ActionResult<Student>> DeleteStudent(int id)
        {
            var student = await _context.Students.FindAsync(id);
            if (student == null)
            {
                return NotFound();
            }

            _context.Students.Remove(student);
            await _context.SaveChangesAsync();

            return student;
        }

        private bool StudentExists(int id)
        {
            return _context.Students.Any(e => e.SId == id);
        }
    }
}

StudentContext.cs

using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;

namespace Students.Models
{
    public class StudentContext:DbContext
    {
        public StudentContext(DbContextOptions<StudentContext> options) : base(options)
        {

        }
        public DbSet<Student> Students { get; set; }
        public DbSet<Department> Departments { get; set; }
    }
}

StudentContextModelSnapshot.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Metadata;
using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
using Students.Models;

namespace Students.Migrations
{
    [DbContext(typeof(StudentContext))]
    partial class StudentContextModelSnapshot : ModelSnapshot
    {
        protected override void BuildModel(ModelBuilder modelBuilder)
        {
#pragma warning disable 612, 618
            modelBuilder
                .HasAnnotation("ProductVersion", "3.0.0")
                .HasAnnotation("Relational:MaxIdentifierLength", 128)
                .HasAnnotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn);

            modelBuilder.Entity("Students.Models.Department", b =>
                {
                    b.Property<int>("Id")
                        .ValueGeneratedOnAdd()
                        .HasColumnType("int")
                        .HasAnnotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn);

                    b.Property<string>("Dep")
                        .IsRequired()
                        .HasColumnType("varchar(20)");

                    b.HasKey("Id");

                    b.ToTable("Departments");
                });

            modelBuilder.Entity("Students.Models.Student", b =>
                {
                    b.Property<int>("SId")
                        .ValueGeneratedOnAdd()
                        .HasColumnType("int")
                        .HasAnnotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn);

                    b.Property<int>("DepartmentId")
                        .HasColumnType("int");

                    b.Property<string>("Name")
                        .IsRequired()
                        .HasColumnType("varchar(50)");

                    b.HasKey("SId");

                    b.HasIndex("DepartmentId");

                    b.ToTable("Students");
                });

            modelBuilder.Entity("Students.Models.Student", b =>
                {
                    b.HasOne("Students.Models.Department", "Department")
                        .WithMany()
                        .HasForeignKey("DepartmentId")
                        .OnDelete(DeleteBehavior.Cascade)
                        .IsRequired();
                });
#pragma warning restore 612, 618
        }
    }
}

Solution

What implementation is required to perform multiple Students entry in database and how to check the same implementation in Postman?

You could add PostStudentList method like below ：

    [HttpPost]
    [Route("StudentList")]
    public async Task<ActionResult<Student>> PostStudentList([FromForm] List<Student> student)
    {
        _context.Students.AddRange(student);
        await _context.SaveChangesAsync();

        return CreatedAtAction("GetStudents", student);
    }

Use Postman to send the list of students with form-data contentType

Updated ,send entries in JSON format

PostStudentList method :

public class StudentVM
    {
        public List<Student> student { get; set; }
    }

    [HttpPost]
    [Route("StudentList")]
    public async Task<ActionResult<Student>> PostStudentList(StudentVM model)
    {
        var students = new List<Student>();
        students = model.student;
        _context.Students.AddRange(students);
        await _context.SaveChangesAsync();

        return CreatedAtAction("GetStudents", students);
    }

Postman: