Migrating to FireDAC from ADO - Stored Proc Param Type

Migrating to FireDAC from ADO - Stored Proc Param Type
Found an interesting little deviation today.  

In a MSSQL stored proc with an TinyInt parameter, the insert statement suddenly complained that it could not insert the param with NULL value (as per constraint).

After a lot of tracing, I was certain that we passed a 0 and not a NULL - and the only plausible reason was that I could see, was that the code was setting the param value, before setting the param datatype - so I rearranged the assignments to ensure that value was the last thing to be set.

That fixed the issue.  Go figure.

Params is Array of Variant.

// ADO, MSSQL
for i := Low(Params) to High(Params) do
begin
  p := AStoredProc.Parameters.AddParameter;
  p.Direction := pdInput;
  p.Value := Params[i];
  p.DataType := VariantTypeToFieldType(VarType(Params[i]));
  if p.Value = null
   then p.Attributes := [paNullable]
  else if VarType(Params[i]) = varBoolean
  then begin
    p.DataType := ftInteger;
    if Params[i]
     then p.Value:=1
      else p.Value:=0;
  end;
end;

// FireDAC, MSSQL
for i := Low(Params) to High(Params) do
begin
  p := AStoredProc.Params.Add;
  p.ParamType := TParamType.ptInput;
  vt := VarType(Params[i]);
  if vt <> vtBoolean
  then begin
    p.DataType := VariantTypeToFieldType(vt);
    p.Value := Params[i];
  end
  else begin
    p.DataType := ftInteger;
    if Params[i]
     then p.Value:=1
      else p.Value:=0;
  end;
end;