Wha datatype is "System:VariableValue" in SSIS? - variables

Question

I need to log every change of variable values in a SSIS, at package level.
I have a SQL Task Editor that receives, as parameters, System::VariableName and System::VariableValue. I use this parameter to log a line in a DB log table.
Everything is working fine BUT... so far i only have numeric variables so, in the "Parameter Mapping", i specificed that the variable with name "System::VariableValue" is a NUMERIC DataType.
What happens when I will have a Datetime variable or a varchar variable? How can I handle variables of different types in this case?
Thankx

Answer 1

Make the datatype sql_variant, which will accommodate the different datatypes.
More on that here: https://msdn.microsoft.com/en-us/library/ms173829.aspx
Also, SSIS does have a on variable changed event which maybe helpful for you, though it sounds like you have a good custom solution.
m
EDIT:
So there is some documentation on MSDN that seems to suggest nvarchar maps to sql_variant. This worked for strings, but left the value empty for numeric values. Looking at the type for Variable.Value in the variables collection in a script task, it notes the type is empty. So I tried setting the data type to null, which did not work at all.
Finally, I created a script task to do the job and this worked correctly. The script task must call a stored proc in order for it to handle all the data types. I tested it with string, int, double and bool, all of which worked correctly.
Here is the table I used:
create table logging (myval sql_variant);
Here is the proc definition:
Create proc [dbo].[insertLog]
#myVal sql_variant
AS
Begin
set nocount on;
insert into logging values(#myVal);
end;
In the OnVariableValueChanged event handler, I added a script task with the following code:
using System.Data.OleDb;
public void Main()
{
// TODO: Add your code here
object val = Dts.Variables["System::VariableValue"].Value;
OleDbConnection conn = new OleDbConnection(Dts.Connections[".\\sql2016.Test"].ConnectionString);
using (conn)
{
conn.Open();
OleDbCommand cmd = new OleDbCommand("insertLog", conn);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("#myVal", val);
cmd.ExecuteNonQuery();
}
Dts.TaskResult = (int)ScriptResults.Success;
}
".\sql2016.Test" is the name of the connection manager in the package.
Please see if this will work for you,
m