当表的列数超过 class 时使用 Dapper

Question

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, eg A,B,C,DI 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.

Answer 1

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);