It depends on the data format. Normally a variable length field is terminated by a delimiter, so a data pattern/regex is not required. Can you describe the format in a little more detail? regards, Tim Kimber, IBM Integration Bus Development (Industry Packs) Hursley, UK Internet: kimbert@uk.ibm.com Tel. 01962-816742 Internal tel. 37246742 From: Bing Lu <mfcplus@yahoo.com> To: "dfdl-wg@ogf.org" <dfdl-wg@ogf.org>, Date: 28/03/2014 03:35 Subject: [DFDL-WG] newbie question Sent by: dfdl-wg-bounces@ogf.org what's the best dfdl approache to describe a variable length alpha numeric field? should i use simpletype restriction pattern, or use dfdl:assert testPattern? thanks in advance-- dfdl-wg mailing list dfdl-wg@ogf.org https://www.ogf.org/mailman/listinfo/dfdl-wg Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU