Enterprise Administration > Implementing Windchill ESI > Implementing Windchill ESI in an SAP Environment > Windchill ESI Assumptions
  
Windchill ESI Assumptions
As mentioned earlier, besides reviewing your business processes and organization’s needs, you also need to review the following assumptions to help you understand how Windchill ESI is designed. Based on this information, you can then decide what configurations to make or if you need to add custom functionality forWindchill ESI to work with your business needs.
• All data validation occurs in Windchill PDMLink to ensure that the required data exists. Data within Windchill PDMLink is valid within itself. You can add additional data validation in Windchill PDMLink.
• XML schema and data from Windchill PDMLink is valid.
• Windchill PDMLink is the system-of-record for material masters, documents, and BOMs/Group BOMs that are created or changed in SAP based on objects published from Windchill PDMLink. In the case of CNs,Windchill PDMLink is the initial master but once the CN is published, the system-of-record control is passed to SAP.
• Once an object is published to SAP, attributes mastered or populated byWindchill PDMLink or the EAI components are not modified in SAP by any other component other than Windchill PDMLink. However, there is no systematic enforcement of security in SAP for part in the material master or document attributes, or on BOM/Group BOMs attributes mastered by Windchill PDMLink.
• All object numbers, BOM numbers and corresponding components, and substitute and document numbers sent fromWindchill PDMLink do not contain lowercase letters. SAP converts lowercase letters in object numbers into uppercase characters, before being stored in the database. For example, if you create a BOM with the number BomA, and then attempt to change BomA you will get an error because the BOM exists as BOMA in the SAP database.
• Document or part numbers sent fromWindchill PDMLink correspond to the SAP external number range configured for material masters. Refer to the section titled "Configuring External Number Ranges for Parts, Documents and CNs" in the Windchill Enterprise Systems Integration Installation and Configuration Guide - SAP for details.
• All revision information, if used, or all version information is generated inWindchill PDMLink and passed to SAP without any transformation.
• Revisions are not created or changed for material masters, BOMs/Group BOMs in SAP without change numbers. The change number must exist in SAP before creating the revision level or before changing or creating the document or the document links.
• Iterations inWindchill PDMLink are not shared with the EAI components. The EAI components only recognize versions. Once a version is published, an iteration is not published to that version.
• Versions are not published out of order from Windchill PDMLink, as described in the following example:
Windchill PDMLink publishes version A to the distribution target.Windchill PDMLink then continues to create versions B and C, but they are never approved to be published.Windchill PDMLink then creates and approves version D to be published. Once version D is approved to be published, the ERP distribution target is sent version D.Windchill PDMLink does not release versions B and C after releasing version D.
• Windchill PDMLink and the distribution targets use the same version scheme (For example, 1234 vs. abcd) for all Windchill ESI objects and versions are always in-sync for published objects.Windchill PDMLink is the system-of-record andWindchill PDMLink controls the versioning.
• Effective date for a part or BOM/Group BOM, if not sent from Windchill PDMLink, is defaulted to the date the part or BOM/Group BOM is committed to the SAP database. CNs are given an effective date of the day they are published to the distribution target.