Map null to DBNull.Value in QueryFile

Author: C0nquistadore

src/Dibix.Http.Server/Runtime/HttpParameterResolver.cs

@@ -579,6 +579,8 @@ private static Expression CollectSourcePropertyValue(IHttpActionDescriptor actio
             if (nullCheckTargets.Any())
             {
                 Expression test = nullCheckTargets.Select(x => Expression.NotEqual(x, Expression.Constant(null))).Aggregate(Expression.AndAlso/* Short-circuit behavior like && in C# */);
+                // DBNull.Value is used when the default value of a method parameter is not set
+                // Slightly confusing...
                 bool hasDefaultValue = parameter.DefaultValue != DBNull.Value && parameter.DefaultValue != null;
                 Expression fallbackValue = hasDefaultValue ? Expression.Constant(parameter.DefaultValue) : Expression.Default(parameter.ParameterType);
                 value = EnsureCorrectType(parameter.InternalParameterName, value, parameter.ParameterType, actionParameter);

src/Dibix/Access/DbCommandParameterCollector.cs

@@ -45,6 +45,7 @@ public override void VisitInputParameter(string name, DbType dataType, object va
                     throw new ArgumentOutOfRangeException(nameof(customInputType), customInputType, null);
             }
 
+            parameter.Value ??= DBNull.Value;
             _command.Parameters.Add(parameter);
         }