Wednesday, December 02, 2015

SAP ABAP INTERVIEW QUESTIONS

SAP (Systems, Applications and Products in Data Processing) is one of the most widely used ERP platforms across the world. Job interviews for SAP modules—whether ABAP, BW/BI, Basis, HANA, FICO, MM, SD, or HR—usually include questions on ERP fundamentals, SAP architecture, ABAP programming, BW concepts, reporting techniques, BDC, data dictionary, and real-time scenarios.

This complete interview guide compiles all important SAP questions in a structured, rewritten, and easy-to-understand format. It covers conceptual, technical, functional, and advanced topics. Whether you are a fresher or an experienced consultant, these questions help you gain deep clarity before interviews.

SECTION 1: BASIC ERP & SAP FUNDAMENTALS

1. What is ERP?

Enterprise Resource Planning (ERP) refers to integrated software solutions designed to manage an organization’s business processes. ERP systems unify functions like finance, production, HR, logistics, supply chain, and sales into a single platform.
The goal is to eliminate redundancy, improve data accuracy, enhance decision-making, and streamline operations.

Originally developed for manufacturing companies, ERP now covers all industries—from retail and banking to healthcare and government organizations.

2. What are the different ERP products?

Several ERP packages exist today. Popular solutions include:

SAP
Oracle / Oracle Financials
PeopleSoft
JD Edwards
BAAN
Siebel CRM

Among these, SAP is the global leader due to its flexibility, robust security, cross-functional integration, and vast module ecosystem.

3. What is SAP?

SAP is an enterprise-grade ERP software developed in 1972 in Germany (Systeme, Anwendungen und Produkte).
It offers comprehensive modules for:

Finance
Sales
Materials
HR
Production
Analytics
Supply Chain
Cloud
CRM

SAP is known for stability, scalability, and real-time business processing.

4. What is Business Content in SAP BW?

Business Content is a pre-built collection of BI objects delivered by SAP. It includes:

InfoCubes
InfoObjects
Queries
Extractors
Update rules
Roles
Workbooks

These ready-made models help companies implement analytics quickly without designing everything from scratch.

5. Why do companies prefer SAP?

Companies adopt SAP because:

Highly configurable
Strong integration across modules
Minimum redundancy, maximum consistency
Secured data processing
Strong global support
Wide industry solutions
Very stable & future-proof

6. Can SAP BW run without SAP R/3?

Yes. BW can load data from:

Flat files
Third-party databases
Non-SAP applications

With mapping tools and ETL connectors, BW can function independently of R/3.

7. What is IDES?

IDES (International Demonstration and Education System) is SAP’s training environment used for learning, demos, and practice.

8. What is SAP Workflow (WF)?

SAP Workflow automates business processes by coordinating:

Users
Tasks
Data
Approvals

Benefits include reduced processing time, lower cost, improved transparency, and better quality.

9. What is SAP R/3?

SAP R/3 is a 3-tier architecture consisting of:

Presentation layer (GUI)
Application layer (business logic)
Database layer (data storage)

It supports multinational business operations.

10. What are presentation, application, and database servers?

Presentation server: The SAP GUI installed on user machines
Application server: Executes ABAP programs, manages logic
Database server: Stores SAP tables and data

SECTION 2: ABAP, DATA DICTIONARY & TECHNICAL CONCEPTS

(✔ All answers rewritten & expanded)

11. What is the approach to writing a BDC program?

Steps:

Extract legacy data → convert into flat file
Load flat file into internal table
Create BDC session or use CALL TRANSACTION
Handle errors
Process session

12. Open SQL vs Native SQL

Open SQL

Database-independent
Works across all SAP-supported DBs
Safer & recommended

Native SQL

Database-specific
Executed directly using EXEC SQL
Not portable across systems

13. What are datasets?

Sequential files processed on the application server using DATASET statements. Used for file handling.

14. Internal table, check table, value table, transparent table

Internal Table: Temporary in-memory table
Check Table: Used for foreign key validation
Value Table: Domain-level fixed values
Transparent Table: 1:1 mapping between DDIC & database

15. Benefits of BW reporting over R/3

High performance
Designed for analytics
Uses OLAP engine
Reduces load on OLTP system

16. How does ERP help business understanding?

Users learn integrated business flows (sales → finance → production), gaining deep operational knowledge.

17. Difference between OLAP & Data Mining

OLAP: Reporting, analysis, predefined queries
Data Mining: Pattern detection, predictive analytics

18. Extended Star Schema

SAP BW separates master data into independent tables linked through SID tables, extending traditional star schema.

19. Meta Data, Master Data, Transaction Data

Meta Data: Data about data
Master Data: Stable long-term data
Transaction Data: Day-to-day business transactions

20. Drawbacks of SAP

Expensive
Complex
Long implementation
Requires skilled staff

ABAP TECHNICAL DEEP DIVE (BDCs, TABLES, DDIC, REPORTING, UI)

This section explains the core ABAP technical building blocks hiring managers test for: internal tables, BDC and Call Transaction, table types, data dictionary elements (domains/data elements), reporting tools (ABAP Query, ALV), screen programming, scripts and forms, transports (CTS) and integration objects (IDocs/RFCs).

Internal Tables, Field Symbols, and Performance

Internal tables are in-memory data structures used heavily in ABAP. They simulate database tables at runtime and are crucial for aggregations, joins, temporary storage and reformatting. Key points:

Types: STANDARD TABLE, SORTED TABLE, HASHED TABLE. Choose based on lookup/update patterns:
- STANDARD — good for appending/looping; index-based access.
- SORTED — keeps data sorted by key; binary search available.
- HASHED — fastest for key-based direct access, no index access.
Use FIELD-SYMBOLS for zero-copy processing (ASSIGN <fs> TO <itab>-line), reducing memory overhead and improving speed.
Use READ TABLE itab WITH KEY carefully — for large tables prefer proper keys or hashed tables.
Use COLLECT to aggregate numeric values into an internal table with a key; APPEND simply adds rows.

Performance tips:

Avoid nested loops over large tables — replace with hashed lookups or sort + binary search.
Use SELECT with INTO TABLE to do bulk fetches; use SELECT fields when you don’t need entire row.
Use proper buffering and indexes on DB tables to reduce I/O.

Data Dictionary (DDIC): Domains, Data Elements, Tables & Indexes

Domain defines the technical attributes of a field: data type, length, decimals, and value ranges.
Data Element gives semantic meaning — short text labels and references to domains. Developers create tables with fields that reference data elements, so UI and reports show meaningful texts.

Table types in DDIC:

Transparent Table: Has a one-to-one mapping in the database. Use for application data.
Pooled Table: Many logical tables stored together in a table pool in the RDBMS. Rarely used for modern apps.
Cluster Table: Groups several related tables stored in a single physical table (cluster). Used for specific SAP scenarios; not common for new developments.
Internal Table: Not a DDIC object; runtime only.

Check table vs Value table:

Check Table: used for foreign key check at field level — ensures relational integrity on input.
Value Table: recommended domain-level default table for value checks.

Indexes:

Add indexes to speed up SELECT queries on frequently filtered fields.
Balance: more indexes = faster reads but slower writes and more space. Choose primary and secondary indexes wisely.

Open SQL vs Native SQL vs EXEC SQL

Open SQL: SAP’s portable subset of SQL. Database independent, recommended for ABAP programs.
Native SQL: Passes DB-specific SQL statements (e.g., Oracle syntax). Use only when DB-specific features are required.
EXEC SQL: Dynamic, embedded SQL using the database’s native syntax — breaks portability and should be used cautiously.

Reporting Tools: ABAP/4 Query, ALV and Interactive Reports

ABAP/4 Query

A no-code or low-code tool to build reports quickly using user groups, functional areas, and logical DBs.
Good for simple reporting needs and rapid prototyping; limited for complex logic.

ALV (ABAP List Viewer)

ALV enhances list output: column sorting, exporting, variants, layouts, and interactive features.
There are several flavors: REUSE_ALV_LIST_DISPLAY, CL_GUI_ALV_GRID, CL_SALV_TABLE (modern OO wrapper).
Use ALV for tabular reports that require dynamic UI features, column dialogs, totals and quick data analysis.

Interactive and Drill-Down Reports

Interactive reports allow the user to double-click rows to trigger secondary logic (AT LINE-SELECTION), creating drill-down navigation.
Use modularization and event-driven logic (selection screen → start-of-selection → top-of-page → end-of-selection → at line-selection) to structure interactive outputs.

BDC (Batch Data Communication) and Call Transaction

When migrating legacy data or automating UI-driven transactions, two common options are:

BDC (Batch Input Sessions)

BDC reads data and simulates user input to SAP screens, storing actions in sessions.
Typical functional modules used:
- BDC_OPEN_GROUP — open session group
- BDC_INSERT — insert records into session
- BDC_CLOSE_GROUP — close session
Sessions can be processed interactively or in background. Use session monitoring and error handling to retry or log failures.
Pros: Mimics exact transaction flow; good for complex screen sequences.
Cons: Sensitive to screen changes and slow compared to direct updates.

CALL TRANSACTION USING (Call Transaction)

CALL TRANSACTION runs the transaction in the same process and can be used for synchronous processing.
Use CALL TRANSACTION ... USING bdcdata MODE 'A' or with BATCH options.
It’s faster than session processing but runs in the same work process and may fail without session recovery.

Alternative to BDC: Use direct API or BAPI calls where available — they are more robust, DB-safe and less dependent on screen flows.

Uploading Data: CATT, LSMW, and Other Tools

CATT (Computer Aided Test Tool) — originally for automated testing and upload; can record transactions and upload data.
LSMW (Legacy System Migration Workbench) — the more modern, supported tool for uploading master data & transactions using recording, conversions, and BAPI/IDoc/Batch input methods.
BAPI and IDoc — recommended when available: standard programmatic interfaces for data exchange.

Steps for CATT/LSMW:

Record transaction or mapping.
Export template.
Prepare and modify source file.
Upload and execute; review logs & errors.

Smart Forms, SAPscript and Layouts

SAPscript

Older SAP printing solution. Components:
- Layout Sets — windows, pages, paragraph and character formats.
- Standard texts and forms assembled by ABAP programs via function modules.
SAPscript uses SAPGUI for design but is being phased out.

Smart Forms

Graphical tool to create forms (in place of SAPscript). Advantages:
- Better UI for designing forms
- Supports colors and improved formatting
- Easier maintenance and faster development
Smart Forms generate a function module which ABAP programs call to print or display documents.

Recommendation: Use Smart Forms (or Adobe Forms in newer landscapes) for print outputs. Migrate old SAPscript where possible.

Screen Programming: DynPro, Screen Painter, Menu Painter, Flow Logic (PBO/PAI)

DynPro (Dynamic Programming) represents SAP screens and their logic. Each screen (DynPro) contains layout and flow logic sections.

Screen Painter: Visual tool to design screen layout components.
Menu Painter: Design menus, GUI status, function keys, titles.
PBO (Process Before Output): Event block executed before screen is rendered — initialize screen fields, set attributes.
PAI (Process After Input): Event block executed after user action — validate input, perform actions, navigate.

Use modular coding, validations in PAI, and minimal code in PBO to keep screens responsive.

Transport Management: CTS (Change & Transport System)

CTS organizes development objects into change requests and transports them across system landscape (DEV → QA → PROD). Key points:

Transport tasks contain objects (programs, table entries, layout sets).
Choose transport strategy: branching, package assignment and authorizations.
Client-dependent objects vs client-independent: ensure correct objects are captured. Certain customizing may require separate transport of customizing requests.

Follow strict CTS policies in team projects: version control, transport locks, and documentation.

Logical Databases & Their Use

Logical databases provide a hierarchical view of related tables and offer built-in GET events and selection functionality. Advantages:

Centralized authorization checks
Reusable selection logic across reports
Improved read performance for hierarchical retrievals

Disadvantages:

Less flexible for complex logic
GET events require specific program structure
Limited to read-only access

ABAP Query can use logical DBs to speed up report creation; otherwise modern approaches rely on Open SQL or AMDP/HANA views.

IDocs and RFC — Integration Interfaces

IDoc (Intermediate Document):

SAP’s standard format for asynchronous data exchange.
Common for EDI, EAI and communication with third-party systems.
IDocs are processed by inbound/outbound ALE layers; map data segments to application logic.

RFC (Remote Function Call):

Synchronous or asynchronous function call mechanism between SAP systems or external programs.
Synchronous RFC (sRFC) — waits for response.
Transactional RFC (tRFC) and Queued RFC (qRFC) — provide guaranteed delivery and transactional integrity for asynchronous processing.

Use IDocs for decoupled, message-based integration and RFC/BAPI for direct, procedural integration.

Error Handling and Debugging in Batch Processes

When batch sessions or background jobs fail:

Check SM35 for session logs.
Review job logs in SM37.
Use ST22 for dump analysis and check short dumps.
For performance, analyze SQL statements with ST05 (SQL trace) and check expensive SELECTs.

For BDC sessions: log failed records, provide retry utilities, and build idempotent import routines to avoid duplicates.

Use ALV for rich interactive reports and ABAP Query for quick reports.Prefer Open SQL for portability; use native SQL sparingly.For data migration, prefer BAPI/IDoc/LSMW over raw screen simulation when possible.Use Smart Forms/Adobe for modern form output; move away from legacy SAPscript.Optimize internal tables and indexes; choose appropriate table type for use case.Organize transports with CTS and maintain strict change control.For integration, choose RFC for synchronous and IDoc for asynchronous scenarios.

SAP BW/BI (Business Warehouse / Business Intelligence) COMPLETE INTERVIEW GUIDE

SAP BW/BI is one of the most crucial parts of SAP’s analytics ecosystem. Companies rely on BW to extract, store, model, and analyze business data. This section covers every major BW concept used in interviews—from InfoCubes and ODS objects to ETL, metadata, and reporting through Business Explorer.

4.1 What Is SAP BW/BI?

SAP BW (Business Warehouse), later evolved into BI (Business Intelligence), is SAP’s enterprise data warehousing solution. It provides a central repository to collect data from multiple SAP and non-SAP systems, clean it, consolidate it, and make it available for reporting and analytics.

Key features:

Data Modeling
Data Extraction
Staging & Transformation
Storage in InfoCubes, DSOs, MultiProviders
Reporting using BEx tools
OLAP processing
Delta loading capabilities

BW is used for high-level analytics, management dashboards, KPIs, and business performance reporting.

4.2 What Is Business Content? (Fully Rewritten)

Business Content is a library of pre-delivered SAP BI objects designed to provide ready-to-use analytics. It includes:

InfoObjects
InfoCubes
DSO/ODS objects
Queries
Workbooks
Update Rules
Transfer Rules
Roles & authorizations
Extractors for SAP modules (FI, CO, HR, MM, SD etc.)

Benefits:

Speeds up implementation
Reduces development efforts
Provides SAP-standard best practices
Ensures compatibility with R/3 and ECC data structures

Companies use Business Content when they want standard analytics without building everything from scratch.

4.3 What Is an InfoCube?

An InfoCube is a multi-dimensional data model used for OLAP reporting. It consists of:

Fact Table → Stores key figures (measures)
Dimension Tables → Store foreign keys for characteristics
SID Tables → Master data reference
Master Data Tables → Attributes, texts, hierarchies

InfoCubes follow the Extended Star Schema, SAP’s optimized model for faster reporting.

4.4 What Is Extended Star Schema?

Extended Star Schema enhances the classical star schema by:

Storing master data (attributes, texts, hierarchies) in separate tables
Keeping dimension tables small
Improving performance of fact table joins
Reusing master data across multiple InfoCubes

Advantages:

Reduced redundancy
Smaller dimension tables → faster joins
Better scalability

4.5 What Is a DSO / ODS Object?

A DSO (Data Store Object) or ODS holds detailed, document-level data at an atomic level.

It consists of:

Active table – final, consolidated data
Change log – delta entries
New data table – staging layer

Use ODS when:

Detailed reports are needed
You need overwrite capability
Change history tracking required
Data acts as staging for InfoCubes

Difference from InfoCube:

Feature	ODS/DSO	InfoCube
Data Type	Transaction-level	Aggregated
Storage	Transparent tables	Multidimensional
Reporting	Detail reporting	Summary reporting
Delta	Overwrite / append	Only append

4.6 What Is AWB (Administrator Workbench)?

AWB is the central cockpit for BW administration.

You use AWB for:

Data modeling
ETL monitoring
Managing InfoObjects
Activating data targets
Checking load failures
Performance tuning
Creating transfer/update rules
Scheduling data loads

Think of AWB as the “control center” for BW operations.

4.7 What Are Transfer Rules & Update Rules?

Transfer Rules

Define how data maps from Source System → Communication Structure.
Used before 7.0 versions; replaced by Transformations later.

Update Rules

Define how data goes from Communication Structure → Data Target (Cube/ODS).

After SAP BI 7.0:

Transfer rules + update rules are replaced with Transformations
Mapping is done using Transformation & DTP (Data Transfer Process)

4.8 What Is an Extractor?

Extractors are mechanisms that retrieve data from SAP/non-SAP source systems into BW. They fill the extract structure for a DataSource.

Types of extractors:

Content extractors (FI, CO, MM, SD, HR etc.)
Logistics cockpit extractors
Generic extractors (table/view/function module)
Delta-capable extractors

Extraction methods:

Full load
Delta load
Init + delta

4.9 Types of Source Systems

BW supports:

SAP R/3 / ECC
SAP BW itself
Flat files (CSV, TXT)
External systems (Oracle, SQL Server, Apps)
Third-party ETL tools (Informatica, DataStage)
Web services / API

4.10 What Is Metadata, Master Data & Transaction Data in BI?

Meta Data

Describes structure of data
Definitions of tables, fields, relationships
Technical/semantic properties

Master Data

Long-term reference data
Example: Customer, Material, Vendor

Transaction Data

Day-to-day business values
Example: Sales quantity, billing records

4.11 What Is BEx? (Business Explorer)

SAP BEx is the BW reporting layer.

It includes:

BEx Analyzer – Excel-based reporting
BEx Query Designer – Build queries
BEx Browser – Launch queries
BEx Web – Web-based analytics
BEx Map – Geo analysis

BEx queries define:

Filters
Key figures
Structures
Variables
Navigational states

4.12 What Are Variables in BEx?

Variables allow dynamic input during query runtime.

Types:

Characteristic variables
Hierarchy variables
Text variables
Formula variables
Processing types (manual input, replacement path, authorization variable)

Used for:

Dynamic filtering
User-specific reports
Reusable query logic

4.13 What Are ODS/DSO Key Features?

Stores detailed transactional data
Supports overwrite capability
Allows delta propagation
Suitable for audit-level reporting
Flat table storage (transparent DB tables)
Acts as staging for InfoCubes

4.14 Explain Delta Loads in BW

Delta load ensures only changed records are loaded after the initial load.

Delta types:

After image
Before image
Additive delta
Delta queue-based
Delta initialization

Delta mechanisms help avoid reading full data sets repeatedly.

4.15 Why Not Use R/3 Directly for Reporting?

Reasons BW is superior:

1. Performance

Heavy OLAP queries slow down OLTP (ECC/R3) systems.

2. Data Consolidation

BW collects data from multiple systems.

3. Historical Storage

ECC stores limited history; BW stores years of data.

4. Predefined Models

SAP provides InfoCubes and extractors for quick analytics.

5. Faster Querying

OLAP engine optimized for analytical queries.

6. Scalability

BW handles massive data loads efficiently.

4.16 AWB Monitoring & Data Load Checks

BW administrators check:

Load failures
Short dumps
Error requests
PSA failures
Delta queue issues
DB locks
Aggregates / compression issues

Tools used:

RSA1 – Administration Workbench
RSMO – Monitor
ST22 – Dumps
SM37 – Background jobs

4.17 What Are InfoObjects?

Basic building blocks of BW.

Two types:

Characteristics → Customer, Material, Plant
Key Figures → Quantity, Sales, Amount

Characteristics have:

Texts
Attributes
Hierarchies

Key figures have:

Aggregation types
Units
Currency conversions

4.18 InfoSet & MultiProvider

InfoSet

Joins multiple ODS/DSO objects
Used for detail reporting
Does NOT support Cubes

MultiProvider

Logical union of multiple InfoProviders
Supports Cubes, DSOs, InfoSets
Used for combined reporting

4.19 What is Open Hub?

Used for exporting BW data to:

Flat files
External DB
3rd-party systems

It supports controlled, scheduled data extraction.

4.20 Administrator Responsibilities (BI Consultant Role)

SAP BI consultants must handle:

Data modeling
Creating Transformations & DTPs
BW queries design
Monitoring data loads
Fixing extractor issues
Performance tuning
Managing master data
Enhancing BI content

✔ ABAP Technical Interview 100+ Questions (FULL REWRITTEN)

including:

BDC
Batch Jobs
LDB
IDocs
RFCs
SAP Scripts
SmartForms
Data Dictionary
Selection Screens
Background Jobs
Table Maintenance
Performance Optimization
5.1 What Is the Typical Structure of an ABAP Program?

ABAP program runs based on events, not sequential execution like normal languages.

Standard structure includes:
- REPORT / PROGRAM statement
- TYPE-POOLS, TYPES, CONSTANTS
- DATA declarations
- SELECTION-SCREEN (optional)
- START-OF-SELECTION (main logic)
- TOP-OF-PAGE, END-OF-PAGE (for reports)
- FORM routines or METHODS
- END-OF-SELECTION
- LIST EVENTS (AT LINE-SELECTION for interactive reports)
ABAP event blocks control program flow, making the structure predictable and modular.

5.2 What Are Field Symbols & Field Groups?

Field Symbols (like pointers in ABAP)

Used for dynamic field access without copying data.
Syntax:
```
FIELD-SYMBOLS <fs> TYPE ANY.
ASSIGN itab-field TO <fs>.
```
Benefits:
- Faster processing
- No memory duplication
- Ideal for loops & dynamic assignments
Field Groups

Used in extract datasets (rare in new projects).
Help structure extract data for sorting/summarizing.

5.3 Best Approach for Writing a BDC Program
1. Record transaction (SHDB).
2. Convert legacy file → internal table.
3. Populate BDC structure (BDCDATA).
4. Use BDC session or CALL TRANSACTION to update SAP.
5. Log errors for reprocessing.
5.4 What Is a Batch Input Session?

A batch input session stores:
- Screens
- Fields
- Values
- Transaction codes
- Sequence of user actions
Sessions are processed later using SM35.

5.5 Alternative to Batch Input Session
- CALL TRANSACTION USING
- BAPI
- IDoc
- LSMW
- Direct Input Programs (DIP)
- BODS (in some landscapes)
5.6 How to Run Program + Batch Session in Background?

Use:
```
SUBMIT <program> VIA JOB <jobname> NUMBER <number>.
```
Process batch session using SM35 with background run.

5.7 Difference Between Pool Table & Transparent Table

Transparent Table
- 1:1 mapping with DB table
- Holds application data
Pooled Table
- Many SAP tables → stored inside one DB table
- Used for small tables like TSTC, TVARV
5.8 Problems While Processing Batch Input Sessions
- Screen changes cause failure
- Missing mandatory fields
- Incorrect field sequence
- Authorizations issues
- Data format mismatches
- Locks on tables
Batch input = slow + screen dependent → better use BAPIs whenever available.

5.9 What Do You Define in Domain & Data Element?

Domain

Technical attributes:
- Type (CHAR, NUMC, DEC, INT etc.)
- Length
- Value range
Data Element

Semantic attributes:
- Field description
- Labels
- Search helps
5.10 Types of Data Dictionary Objects
- Tables (Transparent, Pooled, Cluster)
- Views (Database, Projection, Maintenance, Help)
- Search Helps
- Lock Objects
- Data Elements
- Domains
- Structures
- Table Types
5.11 Types of Tables
1. Transparent
2. Pooled
3. Cluster
5.12 Steps to Create a Table in DDIC
1. Create table → set delivery class
2. Assign fields with elements
3. Define key fields
4. Create technical settings
5. Create indexes
6. Maintain foreign keys
7. Activate table
5.13 Can Transparent Table Exist Without Physical DB Table?

Yes — before activation.
After activation: both dictionary + database are synchronized.

5.14 Can You Create Table Fields Without Data Elements?

Yes, using direct type.
But not recommended because:
- No reusability
- No F4 help
- No description
- Hard to maintain
5.15 Advantages of Structures
- Reusable for internal tables
- Use in global structures
- Simplify modular programming
- Helpful for interface design
5.16 What Does EXTRACT Statement Do?

Used in extract datasets (old reporting).
It collects records for sorting/summarizing before writing output.

5.17 Difference Between COLLECT & APPEND

APPEND

Adds new line.

COLLECT

Aggregates existing line based on key → sums numeric fields.

5.18 Open SQL vs Native SQL

Already covered above.
Open SQL = DB independent
Native SQL = DB-specific

5.19 What Does EXEC SQL Do?

Executes DB-specific SQL code.

Disadvantages:
- Not portable
- No syntax check
- Dangerous if not careful
5.20 ABAP Editor Integrated With DDIC

Means:
- F4 help from dictionary
- Field labels auto picked
- Type checking
- Automatic formatting
5.21 ABAP Events
- INITIALIZATION
- AT SELECTION-SCREEN
- START-OF-SELECTION
- END-OF-SELECTION
- TOP-OF-PAGE
- END-OF-PAGE
- AT LINE-SELECTION
- AT USER-COMMAND
5.22 What Is an Interactive Report?

Classic report with “drill down”.

After user clicks on line:
- AT LINE-SELECTION triggers
- Second list displayed
5.23 Drill Down Report

Multi-level reporting where user navigates to detailed data.
Used in FI/CO/MM/SD analytics.

5.24 How to Write a Function Module

Steps:
1. Go to SE37
2. Create F.M
3. Define import/export parameters
4. Add tables/changing
5. Write logic
6. Activate
7. Assign to Function Group
5.25 Exceptions in FMs

Used for error handling:
```
RAISE no_data.
```
or
Exception numbers.

5.26 What Is a Function Group?

Collection of function modules sharing:
- Global data
- Memory area
5.27 How SAP Stores Date & Time
- DATE → YYYYMMDD
- TIME → HHMMSS
Stored as character type internally.

5.28 Fields in BDC_Tab Table
- Program
- Dynpro
- Dynprostart
- FNAM
- FVAL
5.29 Few Data Dictionary Objects
- Domains
- Data elements
- Tables
- Views
- Search helps
- Lock objects
5.30 What Happens When Table Is Activated?
- Dictionary → DB table created
- Indexes created
- Buffers invalidated
- Metadata updated
5.31 What Is Check Table vs Value Table?

Already covered above.

5.32 What Are Matchcodes?

Old search help mechanism superseded by modern search help.

5.33 Transactions Used for Data Analysis
- SE16 / SE16N
- SQ01 / SQ02 / SQ03
- RSA3 (extract preview)
- RSRT
- LISTCUBE
5.34 Table Maintenance Generator

Used to generate:
- Maintenance dialog
- Insert/update/delete screens
Transaction → SE54 / SM30

5.35 What Are Ranges & Number Ranges?

Ranges

RANGE TYPE: LOW, HIGH, EQ/BT/GE/CP

Number Ranges

Used for generating unique document numbers (FI, MM, SD).

5.36 Select Options vs Parameters

PARAMETERS SELECT-OPTIONS
Single value Multiple values
No intervals Supports ranges
Easy More powerful

5.37 How to Validate Selection Screen?

Use:
```
AT SELECTION-SCREEN.
```
To display default values:
```
INITIALIZATION.
```
5.38 What Are Selection Texts?

Labels used for fields in selection screen (maintained via Goto → Texts).

5.39 CTS (Change Transport System)

Explained in previous section.

5.40 Are Programs Client Dependent?

Standard ABAP programs → client independent
Some SAPscript, variants, TMG → client dependent

5.41 System Global Variables
- SY-DATUM
- SY-UZEIT
- SY-UNAME
- SY-SUBRC
- SY-MANDT
- SY-REPID
5.42 How to Count Internal Table Lines?
```
LINES( itab ).
```
Or:
```
DESCRIBE TABLE itab LINES lv_count.
```
5.43 Performance Techniques
- Use SELECT with WHERE
- Avoid SELECT *
- Use proper indexes
- Use hashed tables for lookups
- Run ST05 SQL trace
- Use parallel cursor technique
5.44 What Are Datasets?

File handling on application server.

5.45 How to Get Return Code of SQL?

Check:
```
SY-SUBRC
```
5.46 Interface / Conversion Programs

Used for:
- Migrating master data
- Migrating transactional data
Tools:
- BDC
- BAPI
- IDoc
- LSMW
5.47 Using SAP Supplied Programs to Load Data

SAP provides:
- RFBIBL00
- RFBIDE00
- RMDATIND
- RM06IBI0
Better use LSMW & BAPI for modern systems.

PARAMETERS	SELECT-OPTIONS
Single value	Multiple values
No intervals	Supports ranges
Easy	More powerful

ADVANCED SAP TECHNICAL (IDocs, RFCs, BAPIs, SAPscripts, Smart Forms, Batch Jobs, Debugging, Screens, Transactions)

This section covers advanced SAP topics that interviewers ALWAYS focus on for experienced ABAP developers. These concepts define your real-time project knowledge, integration understanding, and problem-solving skills.

6.1 What Are IDocs? (Fully Rewritten)

IDoc (Intermediate Document) is a standard SAP data exchange format used for asynchronous communication between systems.

Used in:

EDI interfaces (Orders, Invoices)
Integration with external systems
ALE scenarios (Distributed SAP systems)
Master data transfers
Third-party communication

Key components:

Control Record → Sender, receiver, message type
Data Records → Segments containing actual data
Status Records → Logs (success/failure)

IDoc Types:

Basic Type – SAP-delivered structure
Extension Type – Customized fields
Message Type – Business meaning (ORDERS05, MATMAS etc.)

Processing:

Inbound → External → SAP
Outbound → SAP → External

Transactions:

WE02/WE05 (monitor)
WE19 (test tool)
BD87 (reprocess)

6.2 What Are RFCs (Remote Function Calls)?

RFCs allow two systems to communicate and execute function modules remotely.

Types:

sRFC – Synchronous RFC (waits for response)
tRFC – Transactional RFC (queued + guaranteed delivery)
qRFC – Queued RFC (ensures sequence)
bgRFC – Background RFC (advanced reliable delivery)

Advantages:

Reliable
Fast
Standard SAP communication
Used for BAPI calls across systems

Used in:

SAP integration
Third-party connection
Middleware integration (PI/PO, CPI)

6.3 What Are BAPIs?

BAPI = Business Application Programming Interface.
These are standardized APIs to access SAP business functionality.

Features:

SAP standard
Used for CRUD operations
Stable interfaces
Preferred instead of BDC
Used in integrations, migration, mobile apps

Examples:

BAPI_MATERIAL_SAVE_DATA
BAPI_SALESORDER_CREATEFROMDAT2
BAPI_PO_CREATE1

Advantage over BDC:

Faster
Screen independent
Upgrade safe
Error handling available

6.4 SAP Script & Smart Form Differences

SAPscript	Smart Forms
Older technology	Modern & graphical
Complex maintenance	Easy drag-drop UI
No color/image support	Supports advanced formatting
Multiple windows limited	Rich layout options
Requires driver program	Generates FM automatically

Smartforms recommended for new developments.

6.5 What Is Output Determination?

SAP determines what document prints, how it prints, to whom, and when.

Used in:

Sales order output
Billing document
Purchase order print
Delivery note
Invoice print

Controlled by:

Condition tables
Access sequences
Output types
Procedures

Transactions:

NACE → Configuration
VF31 → Reprint billing

6.6 What Are Screen Painter, Menu Painter & Flow Logic?

Screen Painter

Used for designing DynPro screens:

Input fields
Texts
Tables
Buttons
Subscreens

Menu Painter

Designs GUI elements:

Menu bar
Toolbar buttons
PF keys
Function codes

Flow Logic

Controls screen behavior:

PBO (Process Before Output)

Prepare screen
Set defaults
Manipulate field attributes

PAI (Process After Input)

Validate user input
Trigger function codes
Write back data

6.7 What Are Step Loops?

Step loops are repeated screen blocks used to display multiple records on screen.

Used in:

Table controls
Multi-line data entry screens

Paging (Page up/down) coded in:

LOOP AT statements
Scroll logic

6.8 How Do You Write Transaction Programs in SAP?

Steps:

Build DynPro screens
Assign PBO/PAI events
Write business logic in modules
Create a transaction code in SE93
Link to program
Test navigation, authorization checks

6.9 What Files Are Generated in Transaction Programs?

TOP include
O01 include (PBO)
I01 include (PAI)
C01 include (subroutines)

XXXXXTOP is a default include containing:

Global variables
Data declarations
Type definitions

6.10 Include Programs

Reusable pieces of code:

TOP include
FORM routines
DYNPRO logic
Submodules

Used for modular programming and team development.

6.11 Can You Call Subroutines Across Programs?

Yes.

Using:


PERFORM form_name IN PROGRAM prog_name.

Note:

Must be PUBLIC
Calling program must have access

6.12 What Are User Exits?

User exits allow customer enhancements without modifying SAP standard code.

Types:

Function module exits
Screen exits
Menu exits
Field exits

Tools:

SMOD (exit info)
CMOD (project to implement exit)

Requirement:

Create extra logic inside SAP-approved extension points

6.13 Background Jobs – How to Create?

Used to run programs automatically.

Steps:

Go to SM36
Create job
Assign ABAP program
Set variant
Set schedule (time/event)
Save

Monitor via SM37.

Event-driven jobs trigger when an event occurs:

Finance closing
Data load finish
IDoc arrival

6.14 Host Commands from SAP

Use:


CALL 'SYSTEM' ID 'COMMAND' FIELD lv_cmd.

Or SXPG_COMMAND_EXECUTE.

6.15 Financial Period Tables

Table: T009 (Fiscal year variant)
Controls:

Periods
Special periods
Year shifts

6.16 Does SAP Support Multiple Currencies & Languages?

YES.
SAP is globally enabled.

Supports:

40+ languages
Multi-currency
Unicode
Country-specific configurations

6.17 Currency Factoring Technique

Used for currency conversion (e.g., JPY doesn’t use decimals).
SAP uses factor (100 or 1) to normalize currency calculations.

6.18 How Do You Document ABAP Programs?

Options:

SE38 → Documentation
Program comments
SAPscript texts
Functional/Technical specs
Transport documentation

6.19 SAP Script Commands That Link to Layout Set

WRITE_FORM
OPEN_FORM
CLOSE_FORM
START_FORM
END_FORM

6.20 What Are IDOCs?

Already explained above — asynchronous communication tool.

6.21 What Is Screen Flow Logic?

Two major blocks:

PBO → Before rendering
PAI → After user input

Additional:

MODULE … END MODULE
FIELD statements
CHAIN/ENDCHAIN

6.22 Logical Database Related Questions

Already explained — used in ABAP Query, hierarchical data selection.

6.23 Finding Table Names Behind Transactions

Methods:

Technical help (F1 → F9)
System → Status → Program → Table
Debugger (watch variables)
ST05 SQL trace
SE84 repository search

6.24 IMG – Implementation Guide

IMG is SAP’s configuration tool (SPRO).
Used for:

Customizing
Business processes setup
Functional configuration

6.25 SAP Help & ABAP Editors

Editors:

SE38
SE80
ADT (Eclipse) – Modern and recommended

6.26 Layout Set Elements

Windows
Pages
Paragraph formats
Character formats
Graphic areas

6.27 SAPScript Variables for Output

&VAR& → value
&SY-DATUM& → system date
&VBDKR-VBELN& → table-field variables

6.28 Page Numbering in SAPScript

Use system symbol:


&PAGE& of &SAPSCRIPT-TOTALPAGES&

6.29 Backup SAP Scripts

Use:

RSTXSCRP program for import/export
SE71 → Upload/Download

6.30 Presentation vs Application Server

Presentation server: local PC (GUI)
Application server: runs code & logic

6.31 Accessing Data from Presentation vs Application Server

Presentation → GUI_UPLOAD
Application → DATASET statements

6.32 Data Types in ABAP

Elementary types (C, N, D, T, I, P, F)
Complex types (structures, tables)
Reference types

6.33 BDC vs Call Transaction

BDC Session	Call Transaction
Offline processing	Synchronous
Logs stored	Logs optional
Slower	Faster
Good for large loads	Best for real-time

6.34 Packed Fields for BDC

Packed numbers must be converted to CHAR using:


WRITE var TO charvar.SAP is one of the most powerful and widely adopted ERP platforms in the world, and mastering its concepts—whether technical (ABAP, BW/BI, BDC, IDocs, RFCs) or functional—plays a crucial role in clearing job interviews and excelling in real-time projects. This complete, rewritten guide covered everything from ERP basics and SAP architecture to advanced ABAP programming, data dictionary objects, BI/ BW modeling, extractors, InfoCubes, ODS/DSO, BEx reporting, integration techniques, performance tuning, and real project challenges.
By understanding these questions in depth, a candidate gains clarity on how SAP systems work end-to-end:

✔ how business processes integrate,

✔ how data flows between modules,

✔ how programs interact with tables and transactions,

✔ how interfaces like IDocs/BAPIs connect systems,

✔ and how developers build stable, scalable enterprise solutions.
Whether you are a fresher preparing for your first SAP interview or an experienced professional looking to sharpen your foundational knowledge, this comprehensive article provides a solid, practical, and updated reference. Continue practicing concepts, writing small programs, exploring functional flows, and experimenting in IDES/SAP sandbox systems to build real confidence.
SAP is huge — but with consistent learning and hands-on practice, anyone can master it and build a strong career in the SAP ecosystem.

Tuesday, December 01, 2015

DATA COMMUNICATION AND NETWORKS

DATA COMMUNICATION AND NETWORKS

DATA COMMUNICATION AND NETWORKS

1. Define the term Computer Networks.
A Computer network is a number if computers interconnected by one or more transmission paths. The transmission path often is the telephone line, due to its convenience and universal preserve.
2. Define Data Communication.
Data Communication is the exchange of data (in the form of Os and 1s) between two devices via some form of transmission medium (such as a wire cable).
3. What is the fundamental purpose behind data Communication?
The purpose of data communication is to exchange information between two agents.
4. List out the types of data Communication.
Data Communication is considered
Local – if the communicating device are in the same building.
Remote – if the device are farther apart.
5. Define the terms data and information.
Data: is a representation of facts, concepts and instructions presented in a formalized manner suitable for communication, interpretation or processing by human beings or by automatic means.
Information: is currently assigned to data by means by the conventions applied to those data.
6. What are the fundamental characteristics on which the effectiveness of data communication depends on?
The effectiveness of a data communication system depends on three characteristics.
1. Delivery: The system must deliver data to the correct destination.
2. Accuracy: The system must deliver data accurately.
3. Timeliness: The system must deliver data in a timely manner.
7. Give components of data communication.
1. Message – the message is the information to be communicated.
2. Sender – the sender is the device that sends the data message.
3. Receiver – the receiver is the device that receive the message.
4. Medium – the transmission medium is the physical path by which a message travels from sender to receiver.
5. Protocol – A protocol is a set of rules that govern data communication.
8. Define Network.
A Network is a set of devices (nodes) connected by media links. A node can be a computer, printer, or any other device capable of sending and / or receiving data generated by other nodes on the network.
9. What are the advantage of distributed processing?
1. Security / Encapsulation
2. Distributed database
3. Faster problem solving
4. Security through redundancy
5. Collaborative processing
10. What are the three criteria necessary for an effective and efficient network?
1. Performance
2. Reliability
3. Security
11. Name the factors that affect the performance of a network
-performance of a network depends on a number of factors,
1. Number of users
2. Type of transmission medium
3. Capabilities of the connected hardware
4. Efficiency of software.
12. Name of the factors that affect the performance of a network.
1. Frequency of failure
2. Recovery time of a network after a failure.
3. Catastrophe.
13. Name the factors that affect the security of a network.
Network security issues include protecting data from unauthorized access and viruses.
14. Define PROTOCOL
A protocol is a set of rules (conventions) that govern all aspects of data communication.
15. Give the key elements of protocol.
• Syntax: refers to the structure or format of the data, meaning the order in which they are presented.
• Semantics: refers to the meaning of each section of bits.
1. Timing: refers to two characteristics.
2. When data should be sent and
3. How fast they can be sent.
16. Define line configuration and give its types.
- Line configuration refers to the way two or more
communication devices attach to a link.
- There are two possible line configurations:
i. Point to point and
ii. Multipoint.
17. Define topology and mention the types of topologies.
Topology defines the physical or logical arrangement of links in a network
Types of topology :
- Mesh
- Star
- Tree
- Bus
- Ring
18. Define Hub.
In a star topology, each device has a dedicated point to point link only to a central controller usually called a hub.
19. Give an advantage for each type of network topology.
1. Mesh topology:
* Use of dedicated links guarantees that each connection can carry its own data load, thus eliminating traffic problems.
* Robust and privacy / security.
2. Star topology:
* Less expensive than mesh.
* Needs only one link and one input and output port to connect it any number of others.
* Robustness.
3. Tree topology:
* same as those of a star.
4. Bus topology:
* Ease of installation.
* Uses less cabling than mesh, star or tree topologies.
5. Ring topology:
* A ring is relatively easy to install and reconfigure.
* Each device is linked only to its immediate neighbors.
• Fault isolation is simplified.
20. Define transmission mode and its types.
Transmission mode defines the direction of signal flow between two linked devices.
Transmission modes are of three types.
- Simplex
- Half duplex
- Full duplex.
21. What is LAN?
Local Area Network (LAN) is a network that uses technology designed to span a small geographical area. For e.g. an Ethernet is a LAN technology suitable for use in a single building.
22. What is WAN?
Wide Area Network (WAN) is a network that uses technology designed to span a large geographical area. For e.g. a satellite network is a WAN because a satellite can relay communication across an entire continent. WANs have higher propagation delay than LANs.

DATA COMMUNICATION AND NETWORKS

23. What is MAN?
* A Metropolitan Area Network (MAN) is a network that uses technology designed to extend over an entire city.
* For e.g. a company can use a MAN to connect the LANs in all its offices throughout a city.
24. Define Peer to peer processes.
The processes on each machine that communicate at a given layer are called peer to peer processes.
25. What is half duplex mode?
A transmission mode in which each station can both transmit and receive, but not at the same time.
26. What is full duplex mode?
A transmission mode in which both stations can transmit and receive simultaneously.
27. What is internet?
• When two or more networks are connected they become an internetwork or internet.
• The most notable internet is called the Internet.
28. What is Internet ?
The Internet is a communication system that has brought a wealth of information to out fingertips and organized it for our use.
Internet – Worldwide network.
29. List the layers of OSI model.
- Physical
- Data Link
- Network
- Transport
- Session
- Presentation
- Application.
30. Define OSI model.
The open system Interconnection model is a layered framework for the design of network system that allows for communication across all types of computer systems.
31. Which OSI layers are the network support layers?
- Physical
- Data link
- Network layers.
32. Which OSI layers are the user support layers?
- Session
- Presentation
- Application.
33. What are the responsibilities of physical layer, data link layer, network layer, transport layer, session layer, presentation layer, application layer.
a. Physical layer – Responsible for transmitting individual bits from one node to the next.
b. Data link layer – Responsible for transmitting frames from one node to the next.
c. Network layer – Responsible for the delivery of packets from the original source to the final destination.
d. Transport layer – Responsible for delivery of a message from one process to another.
e. Session layer – To establish, manage and terminate sessions.
f. Presentation layer – Responsible to translate, encrypt and compress data.
g. Application layer – Responsible for providing services to the user. To allow access to network resources.
34. What is the purpose of dialog controller?
The session layer is the network dialog controller. It establishes, maintains and synchronizes the interaction between communicating systems.
35. Name some services provided by the application layer.
Specific services provided by the application layer include the following.
- Network virtual terminal.
- File transfer, access and management (FTAM).
- Mail services.
- Directory services.
36. Define Network Virtual Terminal.
Network Virtual Terminal – OSI remote login protocol. It is an imaginary terminal with a set of standard characteristics that every host understands.
37. Define the term transmission medium.
The transmission medium is the physical path between transmitter and receiver in a data transmission system. The characteristics and quality of data transmission are determined both the nature of signal and nature of the medium.
38. What are the types of transmission media?
Transmission media are divided into two categories. They are as follows:
I. Guided transmission media
II. Unguided transmission media
39. How do guided media differ from unguided media?
A guided media is contained within physical boundaries, while an unguided medium is boundless.
40. What are the three major classes of guided media?
Categories of guided media.
a. Twisted – pair cable.
b. Coaxial cable.
c. Fiber – optic cable.
41. What is a coaxial cable?
A type of cable used for computer network as well as cable television. The name arises from the structure in which a metal shield surrounds a center wire. The shield protects the signal on the inner wire from electrical interference.
42. A light beam travels to a less dense medium. What happens to the beam in each of the following cases:
1. The incident angle is less than the critical angle.
2. The incident angle is equal to the critical angle.
3. The incident angle is greater than the critical angle.
1. The incident angle is less than the critical angle.
the ray refracts and moves closer to the surface.
2. The incident angle is equal to the critical angle.
the light bends along the interface.
3. The incident angle is greater than the critical angle.
the ray reflects and travels again in the denser substance.
43. What is reflection?
When the angle of incident becomes greater than the critical angel, a new phenomenon occurs called reflection.
DATA COMMUNICATION AND NETWORKS
44. Discuss the modes for propagation light along optical channels.
There are two modes for propagating light along optical channels.
Single mode and multimode.
Multimode can be implemented in two forms: step index or graded index.
45. What is the purpose of cladding in an optical fiber? Discuss its density relative to the core.
A glass or plastic is surrounded by a cladding of less dense glass or plastic.
The difference in density of the two materials must be such that a beam of light moving through the core is reflected off the cladding instead of being refracted into it.
46. Name the advantage of optical fiber over twisted pair and coaxial cable.
Higher bandwidth.
Less signal attenuation.
Immunity to electromagnetic interference.
Resistance to corrosive materials.
More immune to tapping.
Light weight.
47. What is the disadvantage of optical fiber as a transmission medium?
Installation / Maintenance.
Unidirectional.
Cost – More expensive than those of other guided media.
48. What does the term modem stands for ?
Modem stands for modulator / demodulator.
49. What is the function of a modulator?
A modulator converts a digital signal into an analog signal using ASK, FSK, PSK or QAM.
50. What is the function of a demodulator?
A de modulator converts an analog signal into a digital signal.
51. What is an Intelligent modems?
Intelligent modems contain software to support a number of additional functions such as automatic answering and dialing.
52. What are the factor that affect the data rate of a link?
The data rate of a link depends on the type of encoding used and the bandwidth of the medium.
53. Define Line coding.
Line coding is the process of converting binary data, a sequence of bits, to a digital signal.
54. For n devices in a network, what is the number of cable links necessary for mesh, ring, bus and star networks.
Number of links for mesh topology : n (n – 1) / 2.
Number of links for ring topology : n – 1.
Number of links for bus topology : one backbone and n drop lines.
Number of links for star topology : n.
55. Write the design issues of datalink layer?
1) Services provided to network layer.
2) Framing
3) Error control
4) Flow control
56. What is datalink?
When a datalink control protocol is used the transmission medium between systems is referred to as a datalink.
57. What is the main function of datalink layer?
The datalink layer transforms the physical layer, a raw transmission facility to a reliable link and is responsible for node to node delivery.
58. What is a datalink protocol?
Datalink protocol is a layer of control present in each communicating device that provides functions such as flow control, error detection and error control.
59. What is meant by flow control?
Flow control is a set of procedures used to restrict the amount of data that the sender can send before waiting for an acknowledgement.
60. How is error controlled in datalink controlled protocol?
In a datalink control protocol, error control is activated by retransmission of damaged frame that have not been acknowledged by other side which requests a retransmission.
61. Discuss the concept of redundancy in error detection.
Error detection uses the concept of redundancy, which means adding extra bits for detecting errors at the destination.
62. What are the three types of redundancy checks used in data communications?
- Vertical Redundancy Check (VRC)
- Longitudinal Redundancy Check (LRC)
- Cyclic Redundancy Check (CRC)
63. How can the parity bit detect a damaged data unit?
In parity check, (a redundant bit) a parity bit is added to every data unit so that the total number of 1s is even for even parity checking function (or odd for odd parity).
64. How can we use the Hamming code to correct a burst error?
By rearranging the order of bit transmission of the data units, the Hamming code can correct burst errors.
DATA COMMUNICATION AND NETWORKS
65. Briefly discuss Stop and Wait method of flow control?
In Stop and Wait of flow control, the sender sends one frame and waits for an acknowledgement before sending the next frame.
66. In the Hamming code for a data unit of m bits how do you compute the number of redundant bits ‘r’ needed?
In the Hamming code, for a data unit of m bits, use the formula 2r > = m + r + 1 to determine r, the number of redundant bits needed.
67. What are three popular ARQ mechanisms?
- Stop and wait ARQ,
- Go – Back – N ARQ and
- Selective Report ARQ.
68. How does ARQ correct an error?
Anytime an error is detected in an exchange, a negative acknowledgment (NAK) is returned and the specified frames are retransmitted.
69. What is the purpose of the timer at the sender site in systems using ARQ?
The sender starts a timer when it sends a frame. If an acknowledgment is not received within an allotted time period, the sender assumes that the frame was lost or damaged and resends it.
70. What is damaged frame?
A damaged frame is recognizable frame that does arrive, but some of the bits are in error (have been altered during transmission)
71. What is HDLC?
HDLC is a bit oriented datalink protocol designed to support both half-duplex and full duplex communication over point to point and multiport link.
72. Give data transfer modes of HDLC?
1. NRM – Normal Response Mode
2. ARM – Asynchronous Response Mode
3. ABM - Asynchronous Balanced Mode
73. How many types of frames HDLC uses?
1. U-Frames
2. I-Frames
3. S-Frame
74. State phases involved in the operation of HDLC?
1. Initialization
2. Data transfer
3. Disconnect
75. What is the meaning of ACK frame?
ACK frame is an indication that a station has received something from another.
76. What is CSMA?
Carrier Sense Multiple Access is a protocol used to sense whether a medium is busy before attempting to transmit.
77. Explain CSMA/CD
Carrier Sense Multiple Access with collision detection is a protocol used to sense whether a medium is busy before transmission but is has the ability to detect whether a transmission has collided with another.
78. State advantage of Ethernet?
1. Inexpensive
2. Easy to install
3. Supports various wiring technologies
79. What is fast Ethernet?
It is the high speed version of Ethernet that supports data transfer rates of 100 Mbps.
80. What is bit stuffing and why it is needed in HDLC?
Bit stuffing is the process of adding one extra 0 whenever there are five consecutive 1s in the data so that the receiver does not mistake the data for a flag. Bit stuffing is needed to handle data transparency.
81. What is a bridge?
Bridge is a hardware networking device used to connect two LANs. A bridge operates at data link layer of the OSI reference model.
82. What is a repeater?
Repeater is a hardware device used to strengthen signals being transmitted on a networks.
83. Define router?
A network layer device that connects networks with different physical media and translates between network architectures.
84. State the functions of bridge?
1. Frame filtering and forwarding
2. Learning the address
3. Routing
85. List any two functions which a bridge cannot perform?
- Bridge cannot determine most efficient path.
- Traffic management function.
86. What is hub?
Networks require a central location to bring media segment together. These central locations are called hubs.
87. State important types of hubs.
1. Passive hub
2. Active hub
3. Intelligent hub
88. Mention the function of hub.
1. Facilitate adding/deleting or moving work stations
2. Extend the length of network
3. It provides centralize management services
4. Provides multiple interfaces.
89. What is the main function of gateway.
A gateway is a protocol converter
90. A gateway operates at which layer.
Gateway operates at all seven layers of OSI model.
91. Which factors a gateway handles?
Data rate, data size, data format
DATA COMMUNICATION AND NETWORKS
92. What is meant by active hub?
A central hub in a network that retransmits the data it receives.
93. What is the function of ACK timer?
ACK timer is used in flow control protocols to determine when to send a separate acknowledgment in the absence of outgoing frame.
94. What are the types of bridges?
1. Transparent bridge
2. Source Routing bridge
Transparent bridge - Transparent bridge keep a suitable of addresses in memory to determine where to send data
Source Routing bridge - Source Routing bridge requires the entire routing table to be included in the transmission and do not route packet intelligently.
95. What are transreceivers?
Transreceivers are combination of transmitter and receiver. Transreceivers are also called as medium attachment unit (MAU)
96. What is the function of NIC?
NIC is used to allow the computer to communicate on the network. It supports transmitting, receiving and controlling traffic with other computers on network.
97. Mention different random access techniques?
1. ALOHA
2. CSMA
3. CSMA/CD
98. What is the function of router?
Routers relay packets among multiple interconnected networks. They route packets from one network to any number of potential destination networks on an internet.
99. How does a router differ from a bridge?
Routers provide links between two separate but same type LANs and are most active at the network layer. Whereas bridges utilize addressing protocols and can affect the flow control of a single LAN; most active at the data link layer.
100. Identify the class and default subnet mask of the IP address 217.65.10.7.
It belongs to class C.
Default subnet mask – 255.255.255.192
101. What are the fields present in IP address?
Netid and Hostid.
Netid – portion of the ip address that identifies the network.
Hostid – portion of the ip address that identifies the host or router on the networks.
102. What is flow control?
How to keep a fast sender from swamping a slow receiver with data is called flow control.
103. What are the functions of transport layers?
The transport layer is responsible for reliable data delivery. Functions of transport layer
i. Transport layer breaks messages into packets
ii. It performs error recovery if the lower layers are not adequately error free.
iii.Function of flow control if not done adequately at the network layer.
iv.Function of multiplexing and demultiplexing sessions together.
v. This layer can be responsible for setting up and releasing connections across the
network.
104. What is segmentation?
When the size of the data unit received from the upper layer is too long for the network layer datagrams or datalink frame to handle, the transport protocol divides it in to smaller, usuable blocks. The dividing process is called segmentation.
105. What is Transport Control Protocol (TCP)?
The TCP/IP protocol that provides application programs with access to a connection oriented communication service. TCP offers reliable flow controlled delivery. More important TCP accommodates changing conditions in the Internet by adapting its retransmission scheme.
106. Define the term (i) Host (ii) IP
a. Host : An end user’s computer connection to a network. In an internet each computer is classified as a host or a router.
b. IP: Internet Protocol that defines both the format of packet used on a TCP/IP internet and the mechanism for routing a packet to its destination.
107. What is UDP?
User Datagram Protocol is the TCP/IP protocol that provides application program with connectionless communication service.
108. What is the segment?
The unit of data transfer between two devices using TCP is a segment.
109. What is a port?
Applications running on different hosts communicate with TCP with the help of a concept called as ports. A port is a 16 bit unique number allocated to a particular application.
110. What is Socket?
The communication structure needed for socket programming is called socket.
A port identifies a single application on a single computer.
Socket = IP address + Port number
DATA COMMUNICATION AND NETWORKS
111. How TCP differ from the sliding window protocols.
TCP differs from the sliding window protocols in the following ways:
1. When using TCP, applications treat the data sent and received as an arbitrary byte stream. The sending
- TCP module divides the byte stream into a set of packets called segments, and sends individual segments within an IP datagram.
- TCP decides where segment boundaries start and end.
2. The TCP sliding window operates at the byte level rather than the packet (or segment) level. The left and right window edges are byte pointers.
3. Segment boundaries may change at any time. TCP is free to retransmit two adjacent segments each containing 200 bytes of data as a single segment of 400 byte.
4. The size of the send and receive window change dynamically.
112. Explain how the TCP provides the reliability?
A number of mechanisms provide the reliability.
1. Checksum
2. Duplicate data detection
3. Retransmission
4. Sequencing
5. Timers
113. What is a datagram socket?
A structure designed to be used with connectionless protocols such as UDP.
114. What is congestion?
When load on network is greater than its capacity, there is congestion of data packets. Congestion occurs because routers and switches have queues or buffers.
115. Define the term Jitter.
Jitter is the variation in delay for packets belonging to the same flow.
116. What is Configuration management?
Configuration management (CM) is a field of management that focuses on establishing and maintaining consistency of a system or product's performance and its functional and physical attributes with its requirements, design, and operational information throughout its life.
117. What is Fault management?
Fault management is the set of functions that detect, isolate, and correct malfunctions in a telecommunications network, compensate for environmental changes, and include maintaining and examining error logs, accepting and acting on error detection notifications, tracing and identifying faults, carrying out sequences of diagnostics tests, correcting faults, reporting error conditions, and localizing and tracing faults by examining and manipulating database information.
118. What is Performance management?
Performance management includes activities that ensure that goals are consistently being met in an effective and efficient manner. Performance management can focus on the performance of an organization, a department, employee, or even the processes to build a product or service, as well as many other areas.
119. What is Security management?
Security Management is a broad field of management related to asset management, physical security and human resource safety functions. It entails the identification of an organization's information assets and the development, documentation and implementation of policies, standards, procedures and guidelines.
120. What is Accounting management?
Accounting Management is the practical application of management techniques to control and report on the financial health of the organization. This involves the analysis, planning, implementation, and control of programs designed to provide financial data reporting for managerial decision making. This includes the maintenance of bank accounts, developing financial statements, cash flow and financial performance analysis.
DATA COMMUNICATION AND NETWORKS

Wednesday, December 02, 2015

SAP ABAP INTERVIEW QUESTIONS

SECTION 1: BASIC ERP & SAP FUNDAMENTALS

1. What is ERP?

2. What are the different ERP products?

3. What is SAP?

4. What is Business Content in SAP BW?

5. Why do companies prefer SAP?

6. Can SAP BW run without SAP R/3?

7. What is IDES?

8. What is SAP Workflow (WF)?

9. What is SAP R/3?

10. What are presentation, application, and database servers?

SECTION 2: ABAP, DATA DICTIONARY & TECHNICAL CONCEPTS

11. What is the approach to writing a BDC program?

12. Open SQL vs Native SQL

13. What are datasets?

14. Internal table, check table, value table, transparent table

15. Benefits of BW reporting over R/3

16. How does ERP help business understanding?

17. Difference between OLAP & Data Mining

18. Extended Star Schema

19. Meta Data, Master Data, Transaction Data

20. Drawbacks of SAP

ABAP TECHNICAL DEEP DIVE (BDCs, TABLES, DDIC, REPORTING, UI)

Internal Tables, Field Symbols, and Performance

Data Dictionary (DDIC): Domains, Data Elements, Tables & Indexes

Open SQL vs Native SQL vs EXEC SQL

Reporting Tools: ABAP/4 Query, ALV and Interactive Reports

ABAP/4 Query

ALV (ABAP List Viewer)

Interactive and Drill-Down Reports

BDC (Batch Data Communication) and Call Transaction

BDC (Batch Input Sessions)

CALL TRANSACTION USING (Call Transaction)

Uploading Data: CATT, LSMW, and Other Tools

Smart Forms, SAPscript and Layouts

SAPscript

Smart Forms

Screen Programming: DynPro, Screen Painter, Menu Painter, Flow Logic (PBO/PAI)

Transport Management: CTS (Change & Transport System)

Logical Databases & Their Use

IDocs and RFC — Integration Interfaces

Error Handling and Debugging in Batch Processes

SAP BW/BI (Business Warehouse / Business Intelligence) COMPLETE INTERVIEW GUIDE

4.1 What Is SAP BW/BI?

4.2 What Is Business Content? (Fully Rewritten)

4.3 What Is an InfoCube?

4.4 What Is Extended Star Schema?

4.5 What Is a DSO / ODS Object?

4.6 What Is AWB (Administrator Workbench)?

4.7 What Are Transfer Rules & Update Rules?

Transfer Rules

Update Rules

4.8 What Is an Extractor?

4.9 Types of Source Systems

4.10 What Is Metadata, Master Data & Transaction Data in BI?

4.11 What Is BEx? (Business Explorer)

4.12 What Are Variables in BEx?

4.13 What Are ODS/DSO Key Features?

4.14 Explain Delta Loads in BW

4.15 Why Not Use R/3 Directly for Reporting?

1. Performance

2. Data Consolidation

3. Historical Storage

4. Predefined Models

5. Faster Querying

6. Scalability

4.16 AWB Monitoring & Data Load Checks

4.17 What Are InfoObjects?

4.18 InfoSet & MultiProvider

4.19 What is Open Hub?

4.20 Administrator Responsibilities (BI Consultant Role)

✔ ABAP Technical Interview 100+ Questions (FULL REWRITTEN)

5.1 What Is the Typical Structure of an ABAP Program?

5.2 What Are Field Symbols & Field Groups?

Field Symbols (like pointers in ABAP)

Field Groups

5.3 Best Approach for Writing a BDC Program

5.4 What Is a Batch Input Session?