How I can read Parent - Child DataSet into object structure (If it possible)

[IFetisov]

Hello. I'm beginner and don't know fuctionality of this great component. Can someone help me with reading data to object model

    public class Order
    {
        public int OrderId { get; set; }
        public DateTime Date { get; set; }
        public List<Detail> Details { get; set; }
    }
    public class Detail
    {
        public int OrderId { get; set; }
        public string Product { get; set; }
    }

SELECT O.OrderId, O.DateTime, D.Product
FROM Orders O
INNER JOIN Details D ON D.OrderId=O.OrderId

May be I should do so? var x = multi.Read<Order, Detail, Order>((o, d) => { o.Details.Add(d); return o; }, splitOn:"OrderId"); But it returns in collection duplicate records

[tuan-tu-tran]

Hello,

This example may help you: https://github.com/doc212/dapper-issue-1151/blob/master/Program.cs

It's taken mostly from here (One to Many) https://dapper-tutorial.net/result-multi-mapping

If it does not help you, could you clarify what you mean by :

But it returns in collection duplicate records

And maybe provide a more complete example

Also I think this kind of question fits better in StackOverflow (but that's just my opinion)

Cheers.

[rksatheesh]

Hi Everyone I am working on a Dynamic Query Builder logic using Dapper. For One to One Relationship

        dynamic result ;
        dynamic ParentObject = new ExpandoObject();
        dynamic ChildObject = new ExpandoObject();
        ParentObject.ChildObject = ChildObject;
        using (var conn = new SqlConnection(_CONN_STRING))
        {
            string sql = @"Select txtMatterName, 
                            dtpMatterReportedDate, 
                            txtDescription, 
                            TeamName, 
                            Teams.Name from matter_creation left join Teams on TeamName = Teams.Id";
            result = conn.Query<dynamic, dynamic, dynamic>(sql, (parent, child) =>
            {
                parent.ChildObject = child;
                return parent;
            },null, splitOn: "TeamName");

        }

this gave me Parent with one child option of one to one using dynamic object.

        var ParentCollection = new Dictionary<long,dynamic>();
        ParentObject = new ExpandoObject();
        ParentObject.Child = new List<dynamic>();
        using (var conn = new SqlConnection(_CONN_STRING))
        {
            string sql = @"SELECT Teams.[Id] 
                          ,[Name]
                          ,[Description]
                          ,[NumberOfMember], Matter_Creation.TeamName, Matter_Creation.txtMatterName
                          FROM [DB_LCF_SQL].[dbo].[Teams] left join Matter_Creation on  Teams.Id =Matter_Creation.TeamName ";
            result = conn.Query<dynamic, dynamic, dynamic>(sql, (parent, child) =>
            {
                if (ParentCollection.TryGetValue(parent.Id,out dynamic existingParent))
                {
                    parent = existingParent;
                }
                else
                {
                    ParentCollection.Add(parent.Id, parent);
                }
                if (parent.Child == null)
                    parent.Child = new List<dynamic>();
                    
                parent.Child.Add(child);
                 
                    return parent;
            }, null, splitOn: "TeamName");
        }
        var j = ParentCollection;

this gave me one to many parent and child data collection in dictionary. above code works perfectly for me. I am having a question is there is any way to assign the number of dynamic object run time . "conn.Query<dynamic, dynamic, dynamic>(sql, (parent, child) =>" in this line i gave dynamic, dynamic, dynamic helps me to build parent and child but based on the relationship key available in a table, is there is a way to change the number of dynamic object parameter runtime .