Header Data vs Item Data
In SAP R/3 each document is divided into three parts:
- Header data
- Item level
- Schedule lines.
Header data stores the information about the characteristics of the document. Suppose if it is a sales order how a sales order should behave will be defined here. The header data is stored in Header Tables. Header data do not change very frequently.
VBAK is header table for the Sales Documents data which stores the characteristics of Sales Documents data like Sales Document number, date created, time of creation, name of the person created the Sales document and the quotation/inquiry is valid from details.
Item Data stores the characteristics of the items or material like which category it belongs whether it's a service item, deliverable item, package goods, semifinished etc. apart from this different conditions pertaining to this items are mentioned here. The item data is one which changes frequently.
For e.g: VBAP is item table for the sales document which stores the data of Sales document client, material number, sales document item and other material data for that sales document.