Description:  System that records data into an organized database or relational structure based on arrays, unions and other data types for efficient use. Most structured data applications use enterprise databases (SQL or Oracle) to retain these relationships with a User Interface that enables the user to input or retrieve information. Although Structured Data Systems can be used to store individual ESI items, the primary discovery issues arise from the raw relational data stored in table or arrays. Discovery on such systems will require specialized assistance and agreement on the form and nature of the extracted ESI.