11.2020 - 01.2022
Migration of an Online Ticket System​
  • Creation of a database model to provide the basis for the migration objects (Oracle) 
  • Development of
    • integration processes for different kind of sources (APIs, Database)
    • JSON-Objects for transfer via interface APIs (Python)
    • a framework for high performance and reliable data exchange via the APIs using threads and multiprocessin
    • a meta database layer to monitor the migration and to have a restartable process chain
03.2013 - today
Support and enhancements of a DWH for analysis and marketing
  • Support for production problems
  • Consulting for further development
  • Database and ETL migration from SQL-Server 2008 to 2014
  • Implementation of change requests based on SQL-Server, SSIS and Perl
  • Connection of interfaces of several marketing platforms for sales validation
01.2020 - 05.2020
Integration of a new partner company into a central neartime DWH system (EXASOL)
  •  Data integration of a new subsidiary into the central data warehouse
  •  Simplification of existing processes for better scalability
02.2020 - 02.2020
Exasol database audit
  • 360° - Examination of the central DWH
  • Performance analyses of the long runners
  • Preparation of an audit report with recommendations for action
07.2020 - 11.2020
Data Warehouse Migration
  • Analysis and reverse engineering of a legacy DWH subsystem (Oracle – OWB)
  • Dependency analysis as a basis for simplifying the loading processes
  • Creation of recommendations for the subsequent migration to Oracle ODI
04.2019 - 12.2019
Building a DWH within a Hadoop environment

Setup of a DWH within a Hadoop environment

  • Requirements analysis
  • ETL development using a Spark framework and Exasol
  • Improvement of the deployment processes
  • Modeling with DataVault 2.0
07.2017 - 12.2019
Further development of a high-performance neartime DWH system
  • Programming of the software application for the integration of further data sources into the DWH
  • Further development and optimization of the existing software for data processing
  • Consulting on the topics of import framework and datafeed generator
09.2017 - 12.2018
Building a KPI data mart within a streaming analytics framework
  • Programming of ETL processes based on Talend and Exasol
  • Implementation of EU-DSGVO requirements
  • Development of automated robotic tests
  • Development of metadata driven data integration processes
  • Development and optimization of Exasol specific SQL scripts
  • Modeling with DataVault 2.0
01.2014 - 06.2017
Establishment and extension of an interface between campaign management tool and various email providers
  • Reverse engineering of the old interface based on C# with the purpose of creating requirements documentation
  • Lean reimplementation based on Perl and Sqlite with the goal of:
  • easier configuration through YAML
  • higher performance
  • faster adaptation in case of changes in business or technical requirements
  • high robustness with low maintenance effort - extensions of the interface
  • change of the output format from XML to CSV
  • Adaptation of communication by choosing a new email provider
  • Easily configurable, country-specific validation and formatting of customer data for offline mailing
05.2014 - 06.2017
Set-up of a high-performance neartime DWH system (EXASOL) including the integration of several thousand data sources
  • Further development and optimization of an import framework configurable via metadata
  • Development of a generator for the creation of DDL and import definitions based on templates for the fast integration of new sources or in case of source changes
  • Integration of several thousand sources (DBs, CSV, Rest-Apis) in high frequency (half-hourly) with the help of the import framework and Pentaho Dataintegration (PDI)
  • Setup of a high performance DWH based on Exasol
  • Database administration including role-rights concept
  • Set-up of database and data export for campaign management of several countries
03.2013 - 01.2014
Support and enhancements of a customer datamart Campaign management
  • Support for production problems
  • Consulting for further development
  • Implementation of change requests based on SQL-Server and SSIS
11.2012 - 01.2013
Development of a prototype for a BI platform in the e-commerce sector
  • Further development of an import framework configurable via metadata
  • Implementation of further interfaces for this framework
  • Development of the DWH based on SQL-Server, SSIS and the import framework
08.2012 - 11.2012
Development of a data warehouse for an e-commerce online portal
  • Development of a reusable import framework, configurable via metadata, for connecting different source types to the data warehouse based on Perl
  • Implementation of a Google Analytics plugin for this framework 
  • Implementation of ETL procedures based on Pentaho Data Integration and MySQL
  • Development and implementation of database and ETL deployment
01.2012 - 08.2012
Design and implementation of standardized data warehouse rollouts for ventures of an internationally operating e-commerce company
  • Conception of a standardized DWH architecture across all ventures
  • Standardization of hardware, operating system, software, DWH artifacts for all ventures
  • Conception and implementation of a rollout procedure
  • Implementation of the DWH rollout for several ventures
  • Conception and implementation of database backup for Oracle 11g
  • Implementation of uniform loading processes based on Pentaho Data Integration and Oracle 11g
06.2011- 11.2011
Planning and implementation of an operational monitoring and analysis platform for an IVR system based on an open source BI suite
  • Establishment of a new 3-tier architecture with virtualized BI platform based on Pentaho and Linux while observing the strict security requirements of the productive IVR environment
  • Conversion of the existing ETL processes based on SQL server to Pentaho Data Integration with an Oracle database
05.2010 - 04.2011
Migration of a system landscape of an IVR system to a new security-compliant environment
  • Examination of the legacy systems according to security guidelines, especially of the databases (MySQL and Oracle)
  • Identification of security gaps and initiation of measures
  • Development and introduction of a uniform role and rights concept for the database
  • Implementation of the software and database migration from Oracle 9i to the new Oracle 11g
08.2009 - 03.2010
Further development of a campaign management system
  • Implementation of new functionalities based on PL-SQL / Oracle 10g
  • Improvement of software quality by introducing the following measures:
    - Programming guidelines
    - Detailed logging
    - Introduction of version management (Subversion) o Development of a reliable delivery procedure
  • Analysis of operational problems
07.2009 - 08.2009
Migration of a data warehouse to a column-oriented database system (EXASOL)
  • Consolidation of the key figures of the existing datamart
  • Analysis of the existing ETL processes based on Pentaho Data Integration and redesign of the datamart
  • New implementation of the ETL processes based on EXASOL SQL
03.2008 - 06.009
Operational support of applications and databases within an IVR system of a mobile operator
  • Operational support of various mobile applications
  • Operational support of the existing databases (Oracle 9i)
  • Planning and implementation of a highly available Real-Application-Cluster (RAC) database system based on Oracle 10g
  • Planning of the software and database migration from the legacy system to the new Oracle platform
  • Second level support
09.2007 - 02.2008
Integration of carrier preselection billing and revenue data for fixed-line telephony and ADSL into the data warehouse of a mobile operator
  • Analysis, conceptual design and specification
  • Design of the target data model
  • Design and implementation of new ETL processes based on PL-SQL and Oracle 10g
07.2007 - 08.2007
Development of a database for the customer analysis of an online portal of a mail order company
  • Analysis and conceptual design
  • Implementation of new ETL processes based on PL-SQL and Oracle 10g
  • Consolidation and performance optimization of existing ETL processes
09.2006 - 06.2007
Connection of a data warehouse to a new system stack
  • Functional and technical analysis of the source systems of the new stack, in particular the integration backbone (EAI) and the CRM system
  • Analysis of business processes on the old and new stack
  • Requirements analysis of the processes currently relying on the DWH
  • Analysis and evaluation of the information provided by the new stack for the DWH
  • Development of target data models in coordination with the business departments
  • Design of prototypical ETL processes based on PL/SQL under Oracle 9i and Perl
04.2006 - 09.2006
Application management for a billing system
  • Automation of installations
  • Process optimization
  • Introduction of a communication platform and knowledge database based on TWiki
  • Perl training
  • Application monitoring
01.2006 - 03.2006
Design and implementation of a new ETL interface for loading billing data into the DWH system of an online provider
  • Project management
  • Analysis and conceptual design
  • Design of the data model and ETL processes
  • Realization of model, loading processes and the flow control based on Informatica PowerCenter, PL-SQL, Perl and Oracle 9i
  • Technical documentation
11.2005 - 01.2006
Development of a control and reporting tool for process optimization for the DSL reseller change of a fixed network operator
  • Transaction-secured exchange of non-processable change orders with a repair system via an FTP interface, reporting of the repair status via a status model
  • Analysis and conceptual design
  • Rapid prototyping
  • Technical consulting
  • Realization based on Perl and Oracle
11.2004 - 10.2005
Development of services within an SO architecture for a central database server for the contract data of a fixed network operator
  • Creation of technical and data processing concepts
  • design
  • data modeling
  • Development based on C++, DB2 under AIX
  • system test
01.2003 - 11.2004
Data migration from legacy systems to a central database server for the contract data of a fixed network operator

To populate a central database server, the business data is migrated from several distributed legacy systems. While the development takes place on an AIX platform and Postgres (later replaced by DB), the test, acceptance and production environment is under MVS/zOS and DB2.

  •  Creation of business and data processing concepts
  • Design
  • Development based on C++ under AIX
  • Supervision of the build process under MVS/zOS
  • System test under MVS/zOS and DB2
10.2000 - 12.2002
Statistical processing of call data for the data warehouse of a mobile network operator

Further development of a self-developed ETL system for the analysis of CDRs of a billing system

  •  Specification and coordination of the interface to the billing system
  • Implementation of ETL processes based on C, Oracle, Informatica PowerCenter
  • Support of the operation and maintenance of the configuration
  • Test support for porting VMS to a UNIX system
  • Creation of business and data processing concepts
03.2000 - 10.2000
Extension and adaptation of a billing system to the GPRS service of a mobile network operator
  • Realization based on Cobol, C and Oracle under Open VMS 
  • System test