Insert a null value in a table

Question

How to insert a null value in a Table by parameter. For example: command.Parameters.Add(@ImageColumn ****** ); What do I must to write instead of ******* ? I tried this: command.Parameters.Add(@ImageColumn null); But it throws an exception. Any idea? Thanx in advance. Carlos

Carlos Sanchez · Answer

woooooow!!! Really I didn't know the Try Catch block is able to store several exceptions. thanx one more time.

miker · Answer

Make sure that SQLException may contain more than one instance of SQLError. To get them all use something like this (from VS): catch (SqlException e) { for (int i=0; i < e.Errors.Count; i++) { Console.WriteLine(Class: {1} e.Errors[i].Class); Console.WriteLine(Error #{1}: {2} on line {3}. e.Errors[i].Number e.Errors[i].Message e.Errors[i].LineNumber); Console.WriteLine(Error reported by {1} while connected to {2} e.Errors[i].Source e.Errors[i].Server); } }

Carlos Sanchez · Answer

I have allready Used a Try Catch block and I had already haven a better code. Thank U Peter T Jones.

p.jones · Answer

Your code showed no use of a Try Catch block. If you used such around the command execution then you could access the thrown exception structure and you would most likely see what the database error message was.

Carlos Sanchez · Answer

thank you MikeR that was strange I had to do something like this: SqlCommand myCommand = new SqlCommand() myCommand.Connection = myConnection; if (imageValue!=null) { command.CommandText=INSERT TO myTable (ImageColumn) VALUE (@ImageColumn); myCommand.Parameters.Add(@ImageColumn imageValue); } else myCommand.CommandText=INSERT TO myTable (ImageColumn) VALUE (null); myCommand.ExecuteNonQuery(); it's not the best code but it works. Thanx MikeR.

miker · Answer

In debug mode try to find the inner SQL exception to find what really went wrong.

Carlos Sanchez · Answer

Yes it is.

miker · Answer

Is this column in the database nullable?

Carlos Sanchez · Answer

it throws still the exception: An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in system.data.dll Additional information: System error. do you know why? thank you. Carlos

miker · Answer

DBNull.Value