Integration Server 10.3 | Flat File Schema Developer's Guide | Concepts | What is a Flat File Dictionary?
 
What is a Flat File Dictionary?
 
When Should I Create a Flat File Dictionary?
A flat file schema can contain either record definitions or references to record definitions that are stored elsewhere in the namespace in a flat file dictionary. A flat file dictionary is simply a repository for elements that you reference from flat file schemas. This allows you to create record definitions in a dictionary that can be used across multiple flat file schemas. Reusing record definitions reduces the amount of memory consumed by a flat file schema.
Flat file dictionaries are created as namespace elements in the Integration Server and contain definitions of records, composites, and fields. When you change a definition in a flat file dictionary that is referenced in multiple flat file schemas, the element definition is updated automatically in all of the flat file schemas.
Note:
You can reference a flat file dictionary definition in any flat file schema regardless of whether the dictionary and schema are located in the same package.
When creating an element definition in a flat file dictionary, you specify only certain properties. You then specify the remaining properties in the instance of the element definition in a particular flat file schema.