Incrementing And Concatentating Non-Auto Incrementing Fields

My SQL table has the
following columns:













ID – Auto Incrementing
Number_of_Records – Int
Account_Number – Varchar
(Format 1234)
Account_Number_Instance
  – Varchar
 
(Format e.g. 1234-01)
Other_Field1
Other_Field2…etc.



When the Account_Number was
initially inserted into the table, a Stored procedure (not written be me)
 was used to concatenate the Account_Number
and Number_of_Records.
  As a result
the
  Account_Number_Instance became,
e.g. 1234-01, etc.



From the ASPX form we
retrieve each of the fields above, and based on the Number_of_Records an
appropriate number of records were inserted for the Account_Number.
 

 

For Example:

 



Account_Number = 12345
Number_of_Records = 4



The result inserted into the
table were as follows:



ID
        # of Records
            Acct_Number
  
New_Num
  
         Acct_Number_Instance
  â€¦

1
          4
         
                       
            12345

                       
            12345-01

2
          4
         
                       
            12345

                       
            12345-02

3
          4
         
                       
            12345

                       
            12345-03

4
          4
         
                       
            12345

                       
            12345-04

 

Now, I would like to UPDATE
this table, and based on the original Number_of_ Records (4) I want to ADD, for
Account_Number (1234) add an appropriate Number_of_Instances, beginning with
the next incremental number and adding what the New Number of Records input is…




For Example:






            Account_Number = 12345

            New_Num(ber_Of Records) = 3

ID
        # of Records
 
            Acct_Number
    New_Num
            Acct_Number_Instance
   …

1
          4
         
                       
            12345

                       
            12345-01

2
          4
         
                       
            12345

                       
            12345-02

3
          4
         
                       
            12345

                       
            12345-03

4
          4
         
                       
            12345

                       
            12345-04

5
         
          
                       
            12345

            3
         
            12345-05

6
         
          
                       
            12345

            3
         
            12345-06

7
         
          
                       
            12345

            3
         
            12345-07

 

I
do realize that the next time I have to update this Account_Number I am also
going to have to somehow ADD only one of the #_of_Records and New_Num for the
Acct_Number instances to obtain the next starting number, which in the example
above would be (8)…



Any
and all suggestions on how to accomplish this would be greatly appreciated!

Thanks