Performing MERGE with Dapper.net

Question

Performing MERGE with Dapper.net

dapper

Question

We are using Dapper.net for the data layer in an ASP.net MVC 5 app.

One operation requires the use of the MERGE command (if the TitleID exists, update the record, if it doesn't, insert it) - something like this:

MERGE BookInventory bi
USING BookOrder bo
ON bi.TitleID = bo.TitleID
WHEN MATCHED THEN
  UPDATE
  SET bi.Quantity = bi.Quantity + bo.Quantity
WHEN NOT MATCHED BY TARGET THEN
  INSERT (TitleID, Title, Quantity)
  VALUES (bo.TitleID, bo.Title,bo.Quantity);

Can Dapper be used to map values onto this MERGE statement?

I can't find anything on this and it's unclear what the best approach to using MERGE with Dapper.net is?

niico

View more on Stack Overflow

Jan Sommer · Accepted Answer · 5/2/2017 3:51:33 PM

Untested, but this should do the trick:

const string sql = @"
    merge into SomeTable as Target
    using (select @myId AS id) as Source
    on (Target.id = Source.id)
    when matched then
        update set Target.SomeColumn = @myValue
    when not matched by Target then
        insert (SomeColumn) values (@myValue)";

conn.Execute(sql, new { myId = 999, myValue = 123 })

Performing MERGE with Dapper.net

Question

Fastest Dapper Plus Extensions

Popular Answer

Performance

Expression Evaluator