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Hi everyone, have you ever use Dapper in .Net. I use for the first time Dapper orm and I have problem with the cast join queries to a model. For example I have two tables and their names are relatively "groups" and "users". these tables joins with users.id field and groups.creator_id field. Also there are some timestamp fields in these tables. I get just the email_address field from the "users" table. Hovewer, when I join these 2 tables, the timestamp fields does not cast to model correctly.It seems to me date field is casted as min date value. What could be the reason for it? Or cause?
It seems to me date field is casted as min date value. What could be the reason for it? Or cause?
The date field is probably empty or zero. The DateTime type defaults to zero which is the same as the minimum date time.
Take a look in the groups table in the database and make sure the created_at date is not empty.
No, the date fields are filled as in the picture below. Also, when I pull only the category table without joining, it works without any problems.
The screenshot has a creation_date field but the query does not include this field in the result set.
ohh sorry I shared wrong ss. this is correct now
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as you do not show the tables definitions nor the class definitions its hard for us to see what your binding error is. you show select results, we don't know the source. also its odd that you are mapping groups columns to user object properties (but its supported).
also you do not identify which object (user/group) property is null.
my classes like below
with enough information its obvious. dapper maps by column name to property name. you are mapping "created_at" to the user class, but the user class does not have a created_at property. not sure what user property you wanted to map to. just use a column alias to map to the the correct user property.
in fact most of your mapping are wrong. only "Name", "Description" and "Email" are mapped correctly
How do you claim it's incorrect? If it's because I used underscore, your perspective is mistaken. I used "DefaultTypeMap.MatchNamesWithUnderscores = true" for that. Besides, when I ran a regular select query instead of join, the mapping worked correctly anyway :)
How do you claim it's incorrect? If it's because I used underscore, your perspective is mistaken. I used "DefaultTypeMap.MatchNamesWithUnderscores = true" for that. Besides, when I ran a regular select query instead of join, the mapping worked correctly anyway :)
If I understand the Dapper documentation, the splitOn argument splits the result by the column position not the alias. Organize the SELECT so the groups are together ending with the CreatorId followed by the user fields.
wooww it is realy interesting trick :) in that case when I remove creator_id and I use just the email field from users table and I put it to the splitOn, it will split result from email field. But as I understand sort are very important for the fields on there. Fields should be sorted for all tables. Thanks for the great answer @AgaveJoe it is solved my problem
............
Even if underscore is turned on, there is no CreatedAt property for the user class, which is where you are mapping created_at.
in c#, DateTime is a value type and can not be null. min date is the default. if you need null support then define the property as DateTime? (nullable type).
Yes I know this. But there are not null record.
duplicate comments... \\ delete
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I have exactly the same problem.
The date is not null while querying directly in SQL Server management studio
The OP was using the SplitOn feature incorrectly which caused the problem. You've provided no code so we have no idea what the problem might be.
Here is the code
var orderlist = _connexion.Query<ObservableCommande, VersaGateDB.Models.Tier, ObservableCommande>("SELECT c.* , t.* FROM Commande c INNER JOIN Tier t ON t.UID = c.Tier_UID WHERE Statut_Commande_Id = 1", (commande, tier) => {
commande.TierName = tier.Nom;
return commande;
},
splitOn: "UID");
All fields are ok in commande, except DateCreation which is 01/01/0001 instead of the right date (SQL field type is DateTime)
If I understand the openly published Dapper documentation, the splitOn feature slices a record into multiple objects by position of a named column. All the columns on the left side of the split go to one object while the columns on right side of the split go to another object. Unfortunately the code you shared uses a SELECT *, you did not provide the schema, and we do not know the ordinal position of the UID column. I assume all you have to do is fix the SELECT so all the columns for object A are on the left side of UID and the columns that map to object B are on the right side of UID.
Here is the schema used.
I tried several fields for spliton, bnut I never get the date