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On this page I would like to present to a selection of my own projects which will give you a greater insight into what my work entails. This following list is incomplete. Moreover, to protect my customers, I have made them anonymous in most cases.

Project DescriptionCustomer's appraisal
Database Migration and Configuration Optimization (09/2020 - ??/????)
Company:Finanzial Service Provider
Software:Oracle 12c/19c & Tools, SQLDeveloper, ShellUtils
Operating Systems:Linux
  • Migration of multiple databases from Oracle 12.1 to Oracle 19c
  • Creation, establishment and support of the regular patch process (quarterly Oracle CPU/PSU patches via Golden Images)
  • Analysis and unification of structures (configuration, directories, etc)
  • Revision of the backup concept to meet demands
  • Staff training to take over future maintenance


Database Support, Conception, Structuring, Recreation (05/2019 - 08/2020)
Company:IT Service Provider
Software:Oracle 12c & Tools, SQLDeveloper, ShellUtils
Operating Systems:Linux, Solaris (Server); Windows (Desktop)
  • Maintenance incl. creating of scripts to simplify the same, automatisation
  • Analysis and Unification of structures (configuration, directories)
  • Identification of performance bottle-necks and working out possible solutions
  • Identification of general conceptual and structural weaknesses including proposals for their elimination (and, if desired, implementation of the same)
  • Setup Optimisation (restructuring of the databases according to the minimum principle: Removal of unused options, checking for „license traps“ and, if possible, removal of the same)
  • Establishment and Maintenance of regular patch processes (quarterly Oracle CPU/RU patches via Golden Images)
  • Security checks for databases according to CIS and consultance for best possible compliance
  • Formulation and establishment of backup concepts (RMAN)
  • Conceptual design and implementation of a new HA environment (Oracle Data Guard)
  • Migration of databases (transfer from the computer centre of another provider with best possibleretainment of configuration incl. DB Version)
  • Planning, establishing and adjustment of Oracle Resource Manager
  • Documentation (Operating manuals, Wiki, inside of scripts)
  • Staff training


Database Support (12/2018 - 04/2019)
Company:International Bank Institute
Software:Oracle 11g/12c and Tools, SQLDeveloper, ShellUtils
Operating Systems:Unix, Linux, Windows
  • Change Process support and implementation (Rollout)
  • Processing of Incidents
  • Database Maintenance
  • Error Analysis / Troubleshooting
  • Documentation


Database Support (12/2015 - 12/2018)
Software:Oracle 11g/12g and Tools (a.o. SQLPlus, Toad, ShellUtils)
Operating Systems:SunOS, Linux, Windows
  • Supporting and executing the Change-Process (roll-out of changes)
  • Create, manage, and edit PL/SQL packages for database maintenance
  • Adjustment, amendment and correction of PL/SQL code for applications
  • Data correction, Data matching (a.o. with external systems)
  • Database Maintenance
  • Planning, implementation and adjustment of Oracle Resource Manager
  • Analysis of problems and errors
  • Documentation

Not yet available

Database Support (04/2012 - 08/2015)
Software:Oracle 11g and Tools (a.o. SQLPlus, AWR Reports, Toad, ShellUtils
Operating Systems:SunOS, Linux, Windows
  • Audit and test of Database scripts
  • Supporting and executing the Change-Process (roll-out of changes)
  • Create and maintain scripts for the Change-Process
  • Create, manage, and edit PL/SQL packages for database maintenance
  • Create/manage database users
  • Database Maintenance
  • Analysis of problems and errors
  • Documentation

From April 2012 to August 2015, Mr. Rehberg worked as external consultant in the department GCC Credit Risk of the UniCredit Business Integrated Solutions. His tasks included supervising the database part of the Change and Incident Management, as well as the maintenance of database users on our Oracle 11g RAC and Exadata installations.

Mr. Rehberg always fulfilled his tasks faithfully and expedient. Whenever he deemed it necessary he independently created required shell and database scripts to simplify processes and thus increase efficiency – always well documented, to enable his team-mates their comfortable use. He also actively participated in optimizing existing processes with the result, that e.g. the roll-out of database scripts now runs mostly automated, and potential sources of errors have been eliminated or at least reduced.

He provided helpful support to our developers' database questions, and also was available as our department's interface for the database administration team. His analysis and communication on database issues significantly helped identifying and solving of errors. Mr. Rehberg thoroughly and exemplarily documented his work and knowledge gained on project specific structures as well as approaches: they are an excellent source for future reference and initial training of new personnel.

We came to appreciate Mr. Rehberg as competent and reliable partner as well as a good team player. He showed initiative, and performed assigned tasks always successfully to our fullest satisfaction. Thus we regret his leaving, and would always like to work with him again.

DB Tuning, Optimizing (01/2011 - 04/2011)
Company:TV station
Software:Oracle 10g and Tools (a.o. AWR Reports, StatsPack, OSPRep), Toad, ShellUtils
Operating Systems:AIX, Windows
  • Identification of (Performance) bottlenecks
  • Offer possible solutions
  • Identify general weaknesses in conceptions and structures
  • Documentation and Forwarding to the responsible provider for test and implementation

Not available

DB Tuning, Optimization & Maintenance (01/2011 - 03/2012)
Company:Broadcast Company
Software:Oracle 10g and Tools, Grid Control, RMAN, Toad, SQLDeveloper, ShellUtils, Subversion, RPM
Operating Systems:RHEL 4/6, Windows
  • Find and fix database-side performance issues
  • Find application-based performance issues, fix in co-work with development
  • Dokumentation of structures and approaches with an Admin-Wiki
  • Installation of new database environments (Oracle 10g/11g), and automate that process as far as possible (RPMs, scripts, etc.)
  • Plan and realize uniform structures of database installations for best possible serviceability
  • Creation of PL/SQL Packages for (automated) database maintenance
  • Software-Packaging (RPM) for unified installations
  • ...

Not available (but you may see notes on my previous project for this customer, 2007-2009)

Database Development (10/2009 - 12/2010)
Software:Oracle 10g and Tools, SQLDeveloper, ShellUtils
Operating Systems:SLES 9/10, HP-UX, Windows
  • PL/SQL Programming: Adapt and enhance existing application code
  • Adapt Oracle Forms
  • Create and Maintain installation scripts (Unix Shell)
  • Documentation of existing codes


DB Administration and Monitoring (05/2009 - 09/2009)
Software:Oracle 9i..11g and Tools, Grid Control, Toad, SQLDeveloper, ShellUtils
Operating Systems:RHEL/HP-UX/Windows
  • Analysis and documentation of the existing (~50) databases
  • Creation of a FRA monitoring tool
  • DBAs daily work


DB Maintenance, Tuning & Optimization (05/2007 - 04/2009)
Company:Broadcast Company
Software:Oracle 9i/10g and Tools, Grid Control, Tora, SQLDeveloper, ShellUtils, Subversion, CVS, RPM, CFEngine
Operating Systems:RHEL 4/SunOS 5.9
  • Find and fix database-side performance issues
  • Find application-based performance issues, fix in co-work with development
  • Move SQL-Code from applications into the database (Stored Procedures/Packages), as far as possible
  • Dokumentation of structures and approaches with an Admin-Wiki
  • Installation of new database environments (Oracle 9i/10g), and automate that process as far as possible (installation images with Kickstart, RPMs, scripts)
  • Installation and customization of Oracle Enterprise Manager Grid Control
  • Plan and realize uniform structures of database installations for best possible serviceability
  • Creation of PL/SQL Packages for (automated) database maintenance
  • Software-Packaging (RPM) for unified installations
  • ...

Mr. Rehberg led the migration project of our Oracle databases from version 9i to 10g. Amongst his activities was requirements analysis, evaluation, prototyping, design, implementation, quality assurance, testing and live operation, operational optimization, operational automation, documentation.

Due to his sound policies, he designed a completely new database environment, which has since managed growing capacity requirements and complexity as patient as robust. Thus, even the unforeseen doubling of traffic and the sometimes tenfold increase in the peak load on the live site in the following year was without objection dealt with by the systems. The tripling of the production volumes of multimedia content on the Intranet side was processed without any problems. The high-availability of the Oracle database, the necessary integrity of data and systems, and successfully implemented policies for data security have been target-oriented and proven in live operation. On our request, the system was recently operationally optimized in a way, that error handling is done largely automated and can be accurately maintained in an emergency even by a non-DBA.

In addition, he supported our developers including not only the resolution of performance bottlenecks, but also pro-actively design of new and revising existing object structures, as well as optimization of existing SQL code.

All his work was documented by Mr. Rehberg exemplary, so even after the termination of his assignment, it is easy for us to understand and reproduce at any time. His developed and implemented uniform structures, including but not restricted to the RPM packages he created, now enormously ease our maintenance.

A general license verification done by independent testing institutes proved the Oracle systems designed, developed and maintained by Mr. Rehberg consistently corresponded to the commercially procured license and therefore was no need for additional regulations concerning licenses and maintenance.

Thanks to his broad interest and excellent education Mr. Rehberg was also able to contribute to larger project and working groups with journalists and media designers to quickly implement a work order handed down, and accelerate projects effective. General praise was always friendly dealings with his colleagues, his openness to journalistic and technical challenges, as well as the deliberate, systematic approach. His always high level of personal motivation and commitment was a role model for the whole team.

Thus Mr. Rehberg, both in the team and the management was appreciated due to his reliability, teamwork, and being very comfortable. We have learned to appreciate him as a competent contact person, harmonizing perfectly with our team. As an expert in the Oracle environment, he was also available for advice to other departments of our house.

We regret his departure, and would always like to work with him again.

DB CleanUp & UTF-8 Migration (10/2006 - 04/2007)
Software:Oracle 9i and Tools, ShellUtils, Subversion, Sharepoint
Operating Systems:HP-UX/Windows XP
  • Detect and CleanUp orphaned data
  • Backup and CleanUp historical data
  • Database Migration from Latin-1 to UTF-8
  • Dokumentation of planning and realisation
  • Splitting of address and phone data

Supported by our development team concerning our database structures, he promptly presented a strategy and process of identifying and archiving orphaned data and unused database objects, and as well making suggestions for additional constraints to prevent future data inconsistencies. For backup and data cleaning of historical data, he wrote and provided all necessary scripts, and ran the cleaning program successfully within a set timeframe, meeting existing deadlines. Mr. Rehberg also defined a strategy and created scripts to split names in our large pan-European customer database from a single database field into a standard gender, title, last name and first name fields. As well, he did the same sort of data splitting for our phone number fields. Although the schedule was very short for these tasks, he again delivered satisfying results before the deadline date.

Regarding our UTF-8 migration process, his consideration and provision of alternative strategies saved our company approximately three quarters of the estimated database downtime which would have been required by more conservative migration processes. Since we provide 24 hour online availability, uptime is critical to our organization, and Mr. Rehberg's solutions gained us very significant time. He automated most of the migration steps by creating shell and SQL scripts, as well as a database migration package in PL/SQL, which allowed our internal DBA full control of the migration workflow. His concerns have always been "safety first", while continuing to provide the most performance-oriented and schedule-based plans that matched our project goals.

In conclusion I can say that we appreciated having Mr. Rehberg in our team. Based on the work that he provided for our UTF-8 migration project, we have extended his contract for an additional three months to provide similar database related support and activities for an internal data model migration. Without any reservation I can recommend him to other companies, as we would be happy to recruit him again for possible future projects of our own.

Environment support, Common Administration (04/2006 - 08/2006)
Company:O2 Germany
Software:Oracle 8i/9i and Tools, ShellUtils, Remedy CMS
Operating Systems:Solaris/HP-UX/Windows 2000
  • Installation and configuration of Oracle instances on Solaris and HP-UX servers
  • Export/Import of data from/to databases
  • Preparation of workorders for creation, deletion, moving and switching of cluster packages using Remedy CMS, as well as the verification of the accomplished tasks
  • Documentation of environments and workflows (Wiki)
Reorganization of selected datenbases, Common Administration (05/2005 - 03/2006)
Company:O2 Germany
Software:Oracle 8i/9i and Tools, ShellUtils, Remedy ARS/CMS
Operating Systems:Solaris/Citrix/Windows 2000
  • Administration and Maintenance of multiple Oracle 8i/9i instances on Solaris servers, including application support and user account management
  • Installation of Oracle StatsPack as well as
  • Creation of scripts for Reports (PL/SQL, HTML: Statistics and Tuning-Hints)
  • Move datenbases to new hardware
  • Planning, conception, implementation and test of the new instances
  • Analyzis and Tuning including applikation tuning
  • Applying (Oracle-) patches to bugfix binaries

In the period between May 2005 and March 2006, Mr. Rehberg was active in our enterprise as consultant in close cooperation. His duties covered the administration and servicing of several Oracle instances of the versions and in production and test environments, running on several Solaris 8 servers. In this context, Mr. Rehberg independently provided the required scripts for the Unix Shell as well as SQL and PL/SQL database layers. Together with the respective development teams he optimised databases and database access, server- and application-sided. Moreover, he attended the relocation of several databases to new hardware as well as the planning and installation of additionally required instances.

His works and thereby obtained knowledge on enterprise-specific structures and workflows have been documented and made available in a knowledge-base. With this knowledge-base a respectable source base could be also provided for the training of new colleagues.

We recommend the services of Mr. Rehberg. He significantly contributed to the success of the projects. Within the scope of the collaboration we got to know Mr. Rehberg as a reliable, targeted, and competent partner. The projects transferred to him were always carried out successfully to our utter satisfaction.

Administration of Oracle 8i/9i Databases, Development (10/2003 - 12/2004)
Software:Oracle 8i/9i and Tools, ShellUtils, CVS
OS:Linux/Solaris/Windows 2000
  • Administration and Monitoring of multiple Instances of Oracle 8i/9i on different machines
  • Establishment of Oracle StatsPack as well as
  • Creation of scripts for reports (PL/SQL, HTML: Statistics and tuning hints)
  • Development of complex queries for DataWareHousing plus appropriate FrontEnds (HTML,Perl)

The Consultant was active from October, 2003 to November, 2004 as a freelance Oracle database administrator in our house.

His area of responsibility enclosed, on this occasion, the administration of several 8.1.7, 9.0.1 as well as 9.2 Oracle databases under RedHat Linux AS 2/3 and Sun Solaris 8, the development of complex queries for the Datawarehousing incl. accompanying Frontends by means of PL/SQL, HTML and Perl as well as the detailed documentation of the existing systems and processes in the database peripherie.

The employee always showed big interest and used any time all possibilities to make himself close with the works in the project team and the operational context. He recognized problem formulations independently and was open minded with new tasks. His expertises contributed substantially to the solution of difficult and complicated problems - by his work the Consultant has performed a determining contribution to the optimization of the system and the system processes. He overlooked difficult connections, recognized essentials and were able to quickly find right the solutions. On account of his application, his abilities and his good view gift he got used to the work any time with big success in new fields of application. He always showed initiative and persuaded by his achievement readiness. Even in difficult situations he was able of an independent and appropriate judgment. Especially is to be emphasized also his ability to document engineering contents in technically understandable drafts. The Consultant distinguished himself by high independence and flexibility. In addition, he worked always reliably, exactly and efficiently. He did justice to the requirements put to him any time.

The personal behavior of the Consultant towards superiors and colleagues was always flawless and distinguished itself by a good collaboration. Both were informed always on time, entirely and properly. In addition, he acquired to himself the trust and the esteem of his superiors and colleague, and counted as an approved interlocutor. The Consultant is a very good team player. For project suppliers we can recommend him at all costs.

Conception and Creation of the company's representation on the Internet (06/2003 - 07/2003)
Company:Medium-sized trade company
Software:PHP 4.x, MySQL, Apache
  • Creating the Concept (Look & Feel/ Design)
  • Developing structures based on the information to represent
  • Reworking graphics, creating interactivity using JavaScript
  • Creating a "News-Page" for latest informations to be fed by the customer without any knowledge in PHP/HTML (retrieving information using forms, storing them into the database and present them template-controlled)

Straight and competent the consultant helped us through the project. Based on the information to represent, he created a clear structure and pleasing relization of a comfortable to navigate Website that represents our company data in an optimal way. His ability to explain even complicated technical details in an easy and also for laymen comprehensible way was not only an advantage for the project as such, but moreover gave positive impulses to new conceptions of internal processes.
Overall, we found the cooperation with the freelancer very convenient and successful and like to take him again for future projects. Of course he has our commendations.

Conception, creation and maintenance of a website for business partners (02/2003 - 07/2003)
Software:PHP 4.x, PostgreSQL 7.3, Perl, Apache
OS:Linux, BSD
  • First step: adaption of Perl scripts and updating single pages
  • Compilation of a new conception
  • Modularization to create code elements for use on multiple locations plus for re-usability in other projects
  • Database connection to manage customer/partner data (incl. registrations and logins)
  • Website protection based on Apache (.htaccess) and PHP (database based session/user management)

The consultant convinces by having innovative ideas and well thought-out concepts of all tasks involved in the project. With preciseness, diligence and efficiency in conducting an operation, the consultant significantly adds to the success of the project. Moreover, an excellently documented source code allows immediate use for other team members as well as being a model for their own programming. By streaming through the client's original site, the consultant quickly recognizes certain patterns and relates its strengths and weaknesses. He then discusses with the client ways to enhance the strengths and illiminate the weaknesses. Based on his established knowlege and experience, the freelancer can present a constructive solution in a short amount of time and consequently implement it in a reliable way. We love working with him and would like to take him on for future projects.

Re-Initiation of several databases (12/2002 - 01/2003)
Software:Oracle 8i and Tools, ShellUtils
OS:IBM AIX 4.3.3 on server side, Windows NT/2000 clients
  • Planning, conception, implementation and test of the instances
  • Set-up of Oracle Names Services for central management of Net8
  • Set-up and configuration of OEM (Oracle Enterprise Manager) for monitoring purposes
  • Creation of scripts for reports (PL/SQL, HTML: statistics and tuning hints)
  • Instruction of employees concerning CVS plus the created structures
Internet/Intranet programming, Oracle 8i administration (09/2000 - 09/2002)
Company:broker agency with 50+ employees
Software:Oracle 8i and Tools, ShellUtils, Apache, PHP 3.x/4.x, MySQL 3.2x
OS:Server: Linux, Solaris; Clients: misc. Windows
  • Oracle Database Administration:
    • Installation/Maintenance of StandAlone and Primary/StandBy environments
    • Performance Tuning and Monitoring
    • Determining, planning and monitoring of ressource usage
    • Planning, conception and realization of Backup/Recovery processes
    • System documentation, also FAQs and HowTos for fast troubleshooting
    • Export/Import/transfers between instances
  • Internet/Intranet Programming:
    • Conception and realization of comparision programs for the customers web portal (Internet brand comparision)
    • Development and maintenance of IntraNet applications for internal data management
    • Installation of runtime environments on the servers

The IT specialist was a hard-working employee. We always were pleased by the quality of his work. He fulfilled his tasks diligently, reliably and efficiently. Moreover, he distinguished himself by his concepts, toughness, versatility and initiative. He showed interest in all business procedures and acted independantly. All together he fullfilled all of the given tasks to our utter satisfaction.

Does anybody completely trust the "appraisal of the appraised"? Since I do not assume such, all appraisals are approved by an external service provider. So if you seek some confirmation, please have a look at Gulp.DE. Unfortunately, you will find the resumes just in the language they were originally penned, which in most case is German.