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c#sql-serverdapper
Neil
Neil

Reputation: 367

Using Dapper when table has more columns than class

In Dapper how do you ignore a table column during an insert?

I have a class with properties A,B,C and have a List of these.

Presume something like

class DTO 
{
    string A;
    string B;
    string C;
}

and the list is of type 

List myList = new List<DTO>()

So with a line of sql like this to bulk insert the list into my table

sql="INSERT INTO TABLE VALUES (@A,  @B, @C)";
conn.Execute(sql, myList)

It works fine and inserts all my data when my table also has columns A,B,C.

But when my table has more columns, e.g. A,B,C,D I get the error: Column name or number of supplied values does not match table definition

I know how to ignore class properties using the Dapper Contrib library, but not the other way round.

How can I do this?

Thanks.

Upvotes: 2

Views: 1371

Answers (1)

Robert Harvey
Robert Harvey

Reputation: 180777

You have to enumerate your columns specifically, as in:

sql="INSERT INTO TABLE (column1name, column2name, column3name) VALUES (@A,  @B, @C)";

Alternatively, if your DTO contains a primary key, you can decorate your DTO with the following attributes:

[Table("TableName")]
class DTO 
{
    [Key]
    int id;
    string A;
    string B;
    string C;
}

and use Insert() from Dapper.Contrib.

connection.Insert(dto);

Upvotes: 2

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