Marcus Kühl - Senior APEX Software Developer, Oracle

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Berlin, Germany

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Experience

May 2025 - Present

1 year 5 months

Senior Software Developer (APEX)

Various

Further development and tuning of a medium-sized application for managing events and participants
Identification of bottlenecks
Adding missing foreign keys and indexes
Reprogramming views and SQL queries in APEX
Report development with Jasper Reports
Mentoring other APEX developers

Jan 2021 - Aug 2024

3 years 8 months

Lead Software Developer (APEX)

Digital Funding Platform

Development of a very large application for online applications for EU funding
Development and presentation of a prototype
Making application design decisions in cooperation with the REs
Development of supporting applications, e.g. for application configuration and management of application processes
Design of important parts of the application, e.g. user guidance, funding-application-specific dynamic menu, configurable uploads, generation of the funding application summary
Anpassung des CSS-Layouts der Anwendung, Einführung geeigneter Klassen zur globalen Formatierung
Development of complex views with the help of views
Mentoring APEX developers
Contact person for the REs and business department regarding questions about the feasibility of requirements in APEX

Sep 2020 - Oct 2020

2 months

Consultant

Development of a Pharmacovigilance Intelligence Tracking System

Development of a prototype for a pharmacovigilance application in APEX 20.1
Creation of the database and APEX application in the Oracle Cloud
Alert inbound screen with faceted search and file upload for document attachments
Simple impact assessment workflow with signature section
Email sending
Dashboard and calendar
Two-hour presentation of the prototype and the basic APEX architecture

Jan 2014 - Jan 2020

6 years 1 month

Senior Software Developer

Roche Basel

Documented DWH reports, including reports for health authorities
Implementation of medical use cases in DWH queries such as event search with MedDRA terms and classification (LLT, PT, HLT, HLGT, SOC), primary path / multipath
Unexpected events based on different labelings such as IB, CDS, EUSPC or country-specific labeling information
SUSAR cases for specific countries, medicines, events, studies
SMQs (Standard MedDRA Queries) and Algorithmic MedDRA Queries (ABC Terms)
SQL tuning and complex regex searches in case narratives
Application development with Oracle Application Express (APEX)
Validations, code reviews, tuning and documentation
GVP trainings (Good Pharmacovigilance Practices)
International project (project language English)

Jan 2012 - Dec 2013

2 years

Senior Software Developer, Tester

Siemens AG

Development of various test programs for the European Train Control System (ETCS)
Module, integration and validation tests
Code reviews and reviews of specifications
International project (English and German)

Jun 2010 - Mar 2012

1 year 10 months

Senior Software Developer

Roche Basel

Helped design and implement a new flat table datamart with SCD Type II
Validation documentation (UR, SDS)
Programming data load jobs
View layer generation
PL/SQL packages to support reporting
Migration of various reports and SQL tuning
Reports according to business requirements

Jan 2010 - Apr 2010

4 months

Senior Software Developer

Kassenärztliche Vereinigung Bayern

Developed an Oracle Application Express application for building test groups for practice comparisons in efficiency audits
Authentication via MS Active Directory (LDAP)
Proxy user, session state protection, and encryption
Generator for online help
SQL tuning
Set up database jobs to load the required data from the doctor directory
Input validation with Oracle regular expressions
Report development

Jul 2008 - Jun 2009

1 year

Senior Software Developer

T-Mobile

Technical design of data storage and data processing for SMS and email sending as well as DWH export
Data model extension
Implementation of web services in C++ and PL/SQL development
MFC GUI development
Technical documentation and operation manuals

Sep 2006 - Jul 2008

1 year 11 months

Software Developer

Boehringer Ingelheim

Created validation documentation such as requirements and software design specifications, installation plans, traceability matrix, etc.
Specified, developed, and documented a reporting application for legacy data using Oracle Application Express 3.0
Analyzed migration scripts from the software vendor and performed database-side analysis of migration errors
Developed distribution rules in PL/SQL (distribution rules)
Planned and carried out migration tests

Jun 2006 - Sep 2006

4 months

Software Developer

Imaging Solutions AG

Created UML class model
Implemented using in-house libraries, librsvg, and Cairo plugin
Developed a Gnome Virtual File System module
Ported existing libraries to Linux
Documentation with Doxygen

Apr 2005 - Jun 2006

1 year 3 months

Software Developer

Kassenärztliche Vereinigung Bayern

Development of the KVB doctor directory
Development and further improvement of various other applications
Report development

Mar 2002 - Sep 2002

7 months

Software Developer C++

Heidelberger Druckmaschinen AG

Design and implementation of a CORBA subscription server (Observer pattern)
Persistent storage management based on memory-mapped files
Development of several CORBA clients for testing and editing
Functional and load testing
Documentation

Jun 2001 - Jan 2002

8 months

Software Developer (Oracle)

Banken und Sparkassen

Takeover, adaptation, and migration of an Oracle 7.3 batch application
Analysis and documentation of job control in the PL/SQL code and database objects
Cleanup of the existing data model
Testing and adaptation of the new model, ensuring interface consistency
Setup of several Oracle instances for development, test, and production
Migration to Oracle 8.1.6
Support of the new production environment
Tuning measures (redo logs, indexes, RBO / CBO)
Support during the EURO conversion

Industry experience

See where this freelancer has spent most of their professional time.

Experienced in Pharmaceutical, Information Technology, Government and Administration, Manufacturing, Healthcare, and Telecommunication.

Pharmaceutical

Information Technology

Government and Administration

Manufacturing

Healthcare

Telecommunication

Business area experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Quality Assurance, Business Intelligence, and Product Development.

Information Technology

Quality Assurance

Business Intelligence

Product Development

Summary

Senior Oracle Developer, Senior APEX Developer

Skills

Oracle Database Oracle 7 – 23
Oracle Cloud Autonomous Database (Oci)
Oracle Application Express - Apex Version 3 To 24.2
Development Of Apex Applications
Tuning Of Apex Applications
Gui Design, If Needed In Coordination With The Customer'S Business Departments
Development Of Very Complex Pages (E.G. Hierarchical Views With Grouping On Different Levels, Reports With Special Formatting, Dynamic Application Menus)
Development Of Report Templates
Development Of Template Components
Restful Data Services
Rest Data Sources (Open Api Definitions, Postman)
User-Defined Authentication / Authorization
Single Sign-On (Ldap), Social Sign-In
Dynamic Actions
Javascript, Css, Html
File Upload / Download, Excel Import
Apex Universal Theme
Customization And Development Of Apex Templates
Mail Templates, Sending Emails
Sql - > 20 Years Of Oracle Sql Experience
Schema Setup
Database Links, External Tables, External Functions
Analytical Functions
Hierarchical Queries
Xml / Sql - Table Mapping
Tuning By Analyzing The Execution Plan
Rewriting Sql Queries
Sql Hints
Index Visibility
Functional Indexes
Pl/Sql - > 20 Years Of Pl/Sql Experience
Sql Generation (E.G. Migration Scripts, Views Or Programs)
Dynamic Functions With Cursor Variables
Autonomous Transactions
Exception Handling
Working With Pragmas
Encryption
Courses With Steven Feuerstein

Languages

German

Native

English

Advanced

Spanish

Intermediate

Education

Dipl. Geologist · Geology

Statistics

Experience

Total positions 13

Experience in Pharmaceutical 9.5 y

Avg length 1 y 7 m

Longest experience 6 y

Expertise

Recent roles Senior Software Developer (APEX), Lead Software Developer (APEX), Consultant

Main industries Pharmaceutical, Information Technology, Government and Administration

Main business areas Information Technology, Quality Assurance, Business Intelligence

Profile

Member since

August 2025

Last update

August 2026

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Frequently asked questions

Have questions? Find more information here.

Marcus is based in Berlin, Germany and can operate in on-site, hybrid, and remote work models.

Marcus speaks the following languages: German (Native), English (Advanced), Spanish (Intermediate).

Marcus has at least 20 years of experience. During this time, Marcus has worked in at least 8 different roles and for 11 different companies. The average length of individual experience is 2 years and 7 months. Note that Marcus may not have shared all experience and actually has more experience.

Based on recent experience, Marcus would be well-suited for roles such as: Senior Software Developer (APEX), Lead Software Developer (APEX), Consultant.

Marcus's most recent position is Senior Software Developer (APEX) at Various.

In recent years, Marcus has worked for Various and Digital Funding Platform.

Marcus is most experienced in industries like Pharmaceutical, Information Technology, and Government and Administration. Marcus also has some experience in Manufacturing, Healthcare, and Telecommunication.

Marcus is most experienced in business areas like Information Technology, Quality Assurance, and Business Intelligence. Marcus also has some experience in Product Development.

Marcus has recently worked in industries like Information Technology and Government and Administration.

Marcus has recently worked in business areas like Information Technology and Product Development.

Marcus attended education in Geology.

The availability of Marcus needs to be confirmed.

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Daily rate avg. 935 €

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Median rate 900 €

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Calculated based on our freelancers’ daily rates as of 7 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.