Value That Is Returned If An Insert Is Not Performed From A SQL Stored Procedure.

I am using the following stored procedure to insert a value into the database.
I am new to stored procedures so I need help. Basically this stored procedure
will only insert a value for "CustomerName" if it is not a duplicate value.

So I noticed in My C# when I call this stored procedure, a negative one "-1"
is returned if the insert is not performed because of a duplicate value.

Is that correct? Should I be getting back a negative one "-1" ? You see
I thought that a Zero "0" would be returned if the insert was not performed.
Not a negative one?


SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE PROCEDURE [dbo].[CustomerCreate]
(
  @CustomerDescription nvarchar(100),
  @CustomerName nvarchar(100),
  @LastUpdateDate datetime,
  @LastUpdateUser nvarchar(32),
  @inserted_record smallint output
)

AS

 if exists (select 1 from Customer where CustomerName = @CustomerName)
 BEGIN

    set @inserted_record = 0

 END
    ELSE BEGIN
 INSERT INTO Customer
 (
  CustomerDescription,
  CustomerName,
        Active,
  LastUpdateDate,
  LastUpdateUser
 )
 VALUES
 (
  @CustomerDescription,
  @CustomerName,
  @LastUpdateDate,
  @LastUpdateUser
 )
 END