SAP Business Processes & ABAP Essentials

Procure-to-Pay (P2P) is the classic cross-module workflow connecting MM and FI. Understanding it clarifies why master data quality matters.

Typical P2P steps:

1. Purchase Requisition (PR) — internal request to buy goods/services (ME51N). May require approval workflow.
2. Purchase Order (PO) — formal commitment to a vendor (ME21N). References material or G/L account, plant, quantity, price.
3. Goods Receipt (GR) — physical receipt posted (MIGO). Inventory increases; GR/IR clearing account updated in FI.
4. Invoice Verification — vendor invoice matched to PO/GR (MIRO). Three-way match: PO, GR, invoice quantities and prices.
5. Payment — outgoing payment clears vendor liability (F-53 / automatic payment run F110).

PR → PO → GR → Invoice → Payment
     MM    MM    MM+FI     FI

Order-to-Cash (O2C) is the sales-side mirror: quotation → sales order → delivery → billing → incoming payment (SD + FI).

Integration points: Each logistics step can generate accounting documents (FI). Errors at GR (wrong plant) propagate to incorrect inventory valuation and mismatched invoices. Process training teaches where to look before jumping into ABAP debug.

SAP data falls into two buckets with different lifecycles and ownership.

Master data — long-lived entities referenced by many transactions:

Object	Module	Examples
Vendor	MM/FI	Payment terms, bank details, reconciliation account
Material	MM/SD	Description, base UoM, valuation class
Customer	SD/FI	Credit limit, pricing procedures, partner functions
G/L Account	FI	Account type, field status group
Cost Center	CO	Controlling area, person responsible

Transactional data — documents created by business events: purchase orders, sales orders, accounting documents, production orders. They reference master data by key (vendor number 100045, material MAT-001).

Golden rules:

• Fix master data once at the source — changing a vendor's reconciliation account affects all future postings.
• Never delete master records with history; use deletion flags or blocks.
• Number ranges and document types control how transactions are numbered and which fields are required.

" Reading vendor master — table LFA1 (general), LFB1 (company code)
SELECT SINGLE name1, land1
  FROM lfa1
  INTO @DATA(ls_vendor)
  WHERE lifnr = @lv_vendor_id.

Data governance teams often own master data; application consultants configure; end users consume it daily.

ABAP (Advanced Business Application Programming) is SAP's primary server-side language. Even functional consultants benefit from reading basic ABAP to troubleshoot custom reports and understand Fiori service backends.

Data types and variables:

DATA: lv_count   TYPE i,
      lv_amount TYPE p DECIMALS 2,
      lv_name   TYPE string.

" Inline declaration (modern ABAP 7.40+)
DATA(lv_today) = sy-datum.

SELECT — reading from the database:

SELECT bukrs, belnr, gjahr, dmbtr
  FROM bkpf
  INTO TABLE @DATA(lt_docs)
  WHERE bukrs = @p_bukrs
    AND budat >= @p_from
  ORDER BY budat DESCENDING
  UP TO 100 ROWS.

Prefer INTO TABLE @DATA(...) with inline declarations. Use @ escaping for host variables. Avoid SELECT * in production — explicit field lists reduce memory and survive schema changes.

CDS views (Core Data Services) — define data models in the ABAP Dictionary with annotations for Fiori and analytics:

@AbapCatalog.viewEnhancementCategory: [#NONE]
@AccessControl.authorizationCheck: #CHECK
define view entity ZC_PurchaseOrder
  as select from ekko
  association [1..*] to ekpo as _Items on $projection.ebeln = _Items.ebeln
{
  key ebeln,
      lifnr,
      bedat,
      _Items
}

CDS views replace many old SE11 views; they power OData services via @OData.publish: true and support calculated fields, associations, and authorization checks declaratively.

Most S/4HANA customers run dual UX during migration: Fiori for day-to-day tasks, SAP GUI for niche transactions not yet app-enabled.

Aspect	SAP GUI	Fiori
Access	SAP Logon / SAP GUI for Java	Browser or mobile app
Navigation	Menu tree + T-codes	Launchpad tiles, search
Look & feel	Dense, multi-screen	Task-focused, responsive
Custom Z-transactions	Full support	Requires OData service + app registration
Power-user features	Multiple sessions, batch input	Simpler; some advanced features delegated to GUI

SAP GUI essentials:

• Command field — type T-codes directly (/nME21N starts fresh PO creation).
• Session management — up to 6 sessions (/o) for parallel work.
• SPRO — IMG configuration tree (consultants, not typical end users).

Fiori essentials:

• Apps identified by Semantic Object + Action (e.g. PurchaseOrder-display).
• Personalization — users pin favorites; theming follows corporate branding.
• Intent-based navigation — one app deep-links to related apps (PO → GR).

Employee guidance: Start in Fiori if your role provides a launchpad. Fall back to GUI T-codes documented in your runbook when no Fiori equivalent exists. Basis teams track Fiori app activation in /UI2/FLPD_CUST and gateway OData registrations (/IWFND/MAINT_SERVICE).