Question

We have tried it using an orm mapper tool, but it opens en closes the connection 750 times. Then we tried to construct a bulk insert, but that goes even slower…

Edit:

CREATE TABLE [dbo].[DataWarehouse](
[DataWarehouseId] [int] IDENTITY(1,1) NOT NULL,
[ColumnName] [nvarchar](max) NOT NULL,
[ColumnValue] [nvarchar](max) NOT NULL,
[RRN] [nvarchar](50) NOT NULL,
[PackageSessionId] [int] NOT NULL,
[AccessCode] [nvarchar](100) NOT NULL,
[Selectie] [nvarchar](150) NOT NULL,
[Date] [smalldatetime] NOT NULL,
[PackageId] [int] NOT NULL,
[Category] [nvarchar](500) NULL,
[OrderId] [int] NOT NULL,
[Category2] [nvarchar](500) NULL,
[TestCode] [nvarchar](200) NULL,
[Category3] [int] NULL,
[QuestionSpecificCategory] [nvarchar](max) NULL,
 CONSTRAINT [PK_DataWarehouse] PRIMARY KEY CLUSTERED 
(
    [DataWarehouseId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF,
 ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

Answer 1

Using a simple SqlCommand should be fast enough for 750 rows, unless you have some really heavy fields, or some very expensive indexes/constraints in the database:

var insert = new SqlCommand("INSERT INTO ...", connection);
var fooParam = insert.Parameters.Add("Foo", SqlType.Int);

for (int i = 0; i < 750; i++)
{
    fooParam.Value = i;
    insert.ExecuteNonQuery();
}