SAP ABAP Developer

Data Types & Variable Declarations

Why: At this level you define the types of a shared structure or class interface that others will use, so a wrong length or type does not spread through every caller.

Internal Tables (Standard, Sorted, Hashed)

Why: Lets you design table keys and access patterns for a nested processing step, so a nightly job that handles large volumes finishes inside its batch window.

Database Tables & Views in DDIC

Why: Lets you decide between a database view, a maintenance view or a table maintenance generator, and set buffering, so users maintain config data safely without a developer.

Open SQL & SELECT Variants

Why: Lets you replace nested SELECTs in loops with a join or FOR ALL ENTRIES and avoid its empty-table trap, so a slow report stops hammering the database.

Classes & Objects

Why: Lets you build a new component as a class with clear visibility and a constructor instead of a function group, so it can be reused and tested in isolation.

Inheritance & Polymorphism

Why: Lets you extend an existing class by redefining one method, such as a processing step for a new document type, without copying the whole class.

Classic Reports & Selection Screens

Why: Lets you deliver a report with a proper selection screen, input validation and event flow, which is still the most common request from finance and logistics users.

ALV (SALV & REUSE_ALV)

Why: Lets you present results in ALV with sorting, totals and a double-click drill-down, so business users can analyse the list without exporting it to a spreadsheet.

Enhancement Framework (BAdIs & Enhancement Spots)

Why: Lets you add custom logic through a BAdI or enhancement spot instead of modifying standard code, so the change survives the next support package.

User Exits & Customer Exits

Why: Lets you maintain and debug the older exits still living in a mature system, for example a sales order user exit, and know when a BAdI is the better choice.