RE: VARLEN field... what good are they?

[Buck Calabro <mcalabro@xxxxxxxxxxxx>]

Brad, 
  For your "length" in the DDS, give a value that covers the needs for most
of your records (i.e. the minimum size).  The DDS manual refers to this as
the fixed size.  This amount is allocated for every record.  Any overflow
is stored in the variable length portion of the file.  An example may
clarify:
Customer master file, name field.  80% of the customers have names that fit
into 25 columns, so you specify your size as 25.  "John Smith" will fit
into the fixed length portion (no overflow).  "HRH Prince Charles Philip
Arthur George" will store "HRH Prince Charles Philip" in the first 25
columns (the fixed portion,) and " Arthur George" in the overflow area (the
variable portion.)

The tradeoff is that is takes more time/effort to get/put information in
the variable area.  That's why you don't simply use a minimum size of 1
column.  In theory, it will be faster to read the record containing "John
Smith" than the one containing "HRH Prince Charles..."  That's the reason
for trying to get as many of your records to fit into the fixed area as
practicable.

Buck Calabro
Billing Concepts, Albany NY
> -----Original Message-----
> From: Stone, Brad V (TC) 
> Sent: Monday, May 17, 1999 9:16 AM
> To:   'MIDRANGE-L@midrange.com'
> Subject:      RE: VARLEN field... what good are they?
> 
> Simon,
> 
> Could you give me an example of how I am supposed to code this in the
> DDS?
> I used the following:
> 
> A character field with a max length of 31000 bytes.  Minimum length of
> 256
> bytes.
> 
> Everything I tried either truncated the data or made a fixed length of
> 31000.  
> 
> From what I understood is that the max length goes in the field length
> paramenter.  Then, you specify on the VARLEN keyword what the minimum
> length
> is.  This didn't work for me and my file grew in size.
> 
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