How do I perform an insert and return inserted identity with Dapper?

Question

How do I perform an insert to database and return inserted identity with Dapper?

I\'ve tried something like this:

string sql = \"DECLARE @ID int; \"          


        

Answer 1

It does support input/output parameters (including RETURN value) if you use DynamicParameters, but in this case the simpler option is simply:

var id = connection.QuerySingle<int>( @"
INSERT INTO [MyTable] ([Stuff]) VALUES (@Stuff);
SELECT CAST(SCOPE_IDENTITY() as int)", new { Stuff = mystuff});

Note that on more recent versions of SQL Server you can use the OUTPUT clause:

var id = connection.QuerySingle<int>( @"
INSERT INTO [MyTable] ([Stuff])
OUTPUT INSERTED.Id
VALUES (@Stuff);", new { Stuff = mystuff});

Answer 2

KB:2019779,"You may receive incorrect values when using SCOPE_IDENTITY() and @@IDENTITY", The OUTPUT clause is the safest mechanism:

string sql = @"
DECLARE @InsertedRows AS TABLE (Id int);
INSERT INTO [MyTable] ([Stuff]) OUTPUT Inserted.Id INTO @InsertedRows
VALUES (@Stuff);
SELECT Id FROM @InsertedRows";

var id = connection.Query<int>(sql, new { Stuff = mystuff}).Single();

Answer 3

Not sure if it was because I'm working against SQL 2000 or not but I had to do this to get it to work.

string sql = "DECLARE @ID int; " +
             "INSERT INTO [MyTable] ([Stuff]) VALUES (@Stuff); " +
             "SET @ID = SCOPE_IDENTITY(); " +
             "SELECT @ID";

var id = connection.Query<int>(sql, new { Stuff = mystuff}).Single();

Answer 4

The InvalidCastException you are getting is due to SCOPE_IDENTITY being a Decimal(38,0).

You can return it as an int by casting it as follows:

string sql = @"
INSERT INTO [MyTable] ([Stuff]) VALUES (@Stuff);
SELECT CAST(SCOPE_IDENTITY() AS INT)";

int id = connection.Query<int>(sql, new { Stuff = mystuff}).Single();

Answer 5

I see answer for sql server, well here it is for MySql using a transaction

    Dim sql As String = "INSERT INTO Empleado (nombres, apepaterno, apematerno, direccion, colonia, cp, municipio, estado, tel, cel, correo, idrol, relojchecadorid, relojchecadorid2, `activo`,`extras`,`rfc`,`nss`,`curp`,`imagen`,sueldoXHra, IMSSCotiza, thumb) VALUES (@nombres, @apepaterno, @apematerno, @direccion, @colonia, @cp, @municipio, @estado, @tel, @cel, @correo, @idrol, @relojchecadorid, @relojchecadorid2, @activo, @extras, @rfc, @nss, @curp, @imagen,@sueldoXHra,@IMSSCotiza, @thumb)"
    
            Using connection As IDbConnection = New MySqlConnection(getConnectionString())
                connection.Open()
                Using transaction = connection.BeginTransaction
                    Dim res = connection.Execute(sql, New With {reg.nombres, reg.apepaterno, reg.apematerno, reg.direccion, reg.colonia, reg.cp, reg.municipio, reg.estado, reg.tel, reg.cel, reg.correo, reg.idrol, reg.relojchecadorid, reg.relojchecadorid2, reg.activo, reg.extras, reg.rfc, reg.nss, reg.curp, reg.imagen, reg.thumb, reg.sueldoXHra, reg.IMSSCotiza}, commandTimeout:=180, transaction:=transaction)
                    lastInsertedId = connection.ExecuteScalar("SELECT LAST_INSERT_ID();", transaction:=transaction)
                    If res > 0 Then 
transaction.Commit()
return true
end if
                    
                End Using
            End Using

Answer 6

There is a great library to make your life easier Dapper.Contrib.Extensions. After including this you can just write:

public int Add(Transaction transaction)
{
        using (IDbConnection db = Connection)
        {
                return (int)db.Insert(transaction);
        }
}