This tutorial demonstrates how to model Toshiba 4690 TLog data by using DFDL schema.
A Transaction Log (TLog) is a complete, detailed record of everything that occurs at a Point of Sale (PoS) terminal, including events that are not directly related to a sales transaction. The precise TLog record format is unique to a given PoS application. This tutorial considers Toshiba (ex-IBM) 4690 ACE v7r5 TLog, a delimited binary format emitted by 4690 PoS terminals.
4690 TLog messages consist of a number of transactions, each of which comprises one or more transaction records (sometimes called 'strings'). Each transaction starts with x'22' and ends with x'220D0A'. Within a transaction, the transaction records are separated by x'222C22'. Within a transaction record, each field is typically separated by x'3A', though some records use x'223A22'. Fields are either ASCII text, hex binary or a BCD variant specific to 4690, and are fixed or variable length.
There are many different types of transaction record, and the first field identifies the type. Some of the record types have sub-types which are identified by a subsequent field or fields. In the DFDL model, the record type field is treated as an initiator, for performance, and record sub-types are identified using a discriminator on the appropriate field(s).
4690 Tlogs are invariably customized by each retailer by adding extra transaction records, typically to the 99 range, or by adding extra fields to the end of records.
The DFDL schema editor is used to view the model and parse example 4690 TLog message files.