Write A LINQ query, How to update(modify) child table data when parent table is inserted [Resolved]

public class Parent
{
    public Parent()
    {
        this.Children = new List<Child>();
    }

    public int Id { get; set; }

    public virtual ICollection<Child> Children { get; set; }
}

public class Child
{
    public int Id { get; set; }

    public int ParentId { get; set; }

    public string Data { get; set; }
}

The below program will do so

public void UpsertChildParent(ParentModel model)
{
    var parent = _dbContext.Parents
        .Where(p => p.Id == model.Id)
        .Include(p => p.Children)
        .SingleOrDefault();

    if (parent != null)
    {
        // Update parent
        _dbContext.Entry(parent).CurrentValues.SetValues(model);

        // Delete children
        foreach (var existingChild in parent.Children.ToList())
        {
            if (!model.Children.Any(c => c.Id == existingChild.Id))
                _dbContext.Children.Remove(existingChild);
        }

        // Update and Insert children
        foreach (var childModel in model.Children)
        {
            var existingChild = parent.Children
                .Where(c => c.Id == childModel.Id)
                .SingleOrDefault();

            if (existingChild != null)
                // Update child
                _dbContext.Entry(existingChild).CurrentValues.SetValues(childModel);
            else
            {
                // Insert child
                var newChild = new Child
                {
                    Data = childModel.Data,
                    //...
                };
                parent.Children.Add(newChild);
            }
        }

        _dbContext.SaveChanges();
    }
}

--
Thanks & Regards,
RNA Team

create table parent(id int primary key,name varchar(40),class varchar(40))

 

create table child(id int foreign key references parent(id), age int,village varchar(50))

DECLARE @pid INT --parent id, where id is identity for parent table



INSERT INTO parent ([name], [class])

VALUES('Name', 'last')

 

SELECT @pid = @@IDENTITY

 

INSERT INTO child(pid, age, village)

VALUES(@pid, 21, 'Village')

Mani.R