How can data be added using Entity Framework Core migration without specifying the id?

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Entity Framework Core provides several ways to generate and manage primary keys while adding data to a database without specifying the id. One approach is to use an auto-incrementing identity column, and another approach is to use a non-identity column with a unique constraint.

To use an auto-incrementing identity column in Entity Framework Core, you can add a property to your entity class with the "Key" attribute and the "DatabaseGenerated" attribute set to "Identity". For example:

public class Product
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
    public string Name { get; set; }
}

When you add a new product to the database using Entity Framework Core, you can set the "Name" property and leave the "Id" property unset. Entity Framework Core will automatically generate a unique id for the new product.

To use a non-identity column with a unique constraint for generating primary keys, you can manually set the primary key value before adding the entity to the database. For example:

public class Product
{
    [Key]
    public string Code { get; set; }
    public string Name { get; set; }
}

When you add a new product to the database using Entity Framework Core, you can set the "Name" property and generate a unique code for the "Code" property. Entity Framework Core will then use the "Code" property as the primary key for the new product.

Note that you should ensure that the "Code" property has a unique constraint in the database table to avoid conflicts.