Interview Question

How can you create multiple new entities in Entity Framework Core?

Answer

EF Core provides several methods to create multiple entities efficiently. Here are the main approaches:

1. Using AddRange Method

using (var context = new ApplicationDbContext())
{
    var customers = new List<Customer>
    {
        new Customer { Name = "John Doe", Email = "john@example.com" },
        new Customer { Name = "Jane Doe", Email = "jane@example.com" }
    };
    
    context.Customers.AddRange(customers);
    await context.SaveChangesAsync();
}

2. Bulk Insert with Third-Party Libraries

// Using EFCore.BulkExtensions
using (var context = new ApplicationDbContext())
{
    var customers = GetCustomerList(); // Your list of customers
    await context.BulkInsertAsync(customers);
}

Key Points 💡

• AddRange is best for small to medium sets of data
• Use bulk insert libraries for large datasets
• Always use transactions for multiple inserts
• Consider batching for very large datasets

Common Follow-up Questions

1. How does bulk insert performance compare to AddRange?
2. How can you handle errors during multiple entity creation?
3. What’s the best way to track the status of bulk operations?