Matthias Guenther, Developer in Antalya, Turkey
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Matthias Guenther

Verified Expert  in Engineering

Database Developer

Location
Antalya, Turkey
Toptal Member Since
June 14, 2021

Matthias is a database developer, modeler, and analyst specializing in CRM development with in-depth knowledge of the retail, fundraising, and automotive industries. Matthias improved response rates archived by an intelligent deduplication process in PL/SQL handling various postal deliverers in the EU. He is an SQL-certified expert who excels with Python, process automation, data quality improvements, proprietary and data management systems, and migrations.

Portfolio

Varda - Main
ETL, Data Modeling, Data Engineering, Python, Apache Kafka, PostgreSQL...
Yara International - Main
ETL, Data Modeling, Data Engineering, Python, Apache Kafka, Redshift...
Freelance
Microsoft SQL Server, Oracle SQL Data Modeler, Oracle SQL Developer...

Experience

Availability

Part-time

Preferred Environment

Oracle SQL Developer, Oracle SQL Data Modeler, MySQL Workbench, Oracle Database, PyCharm, MySQL, Microsoft SQL Server, MariaDB, Amazon Web Services (AWS), PostgreSQL

The most amazing...

...CRM project I led was on an Oracle 12c DB/DWH for a multi-national retail company. The main focus was on data quality, data mining, campaigns, and analytics.

Work Experience

Data Engineer

2022 - 2024
Varda - Main
  • Designed and modeled data models for a global public agricultural field registry API based on a microservice architecture.
  • Ensured high performance of GIS process of the Postgres/PostGIS data lakes.
  • Ensured data integrity and developed data quality-ensuring processes in Python.
Technologies: ETL, Data Modeling, Data Engineering, Python, Apache Kafka, PostgreSQL, RESTful Microservices, Elastic, Geographic Information Systems, Docker, Kubernetes, Amazon RDS, Amazon S3 (AWS S3), Amazon OpenSearch, Amazon EC2, PostGIS, Jenkins, QGIS, GIS, Alembic, SQLAlchemy

Data Engineer

2021 - 2022
Yara International - Main
  • Designed and modeled data models for agricultural data exchange processes.
  • Built and implemented Apache Airflow dbt ETL pipeline processes into the Amazon Redshift database.
  • Ensured data governance for all data lakes and created a data catalog.
Technologies: ETL, Data Modeling, Data Engineering, Python, Apache Kafka, Redshift, Apache Airflow, PostGIS, PostgreSQL, Data Build Tool (dbt), Jenkins, Amazon RDS, Docker, Amazon OpenSearch, Geographic Information Systems, GIS, QGIS, Data Pipelines

Data Engineer

2016 - 2021
Freelance
  • Created a DevOps pipeline to release Java applications to the customer.
  • Built data modeling and database objects in MySQL and Microsoft SQL Server.
  • Delivered requirements engineering, customizing, testing, project management, and bug fixing in Java with various customers in the automotive sector.
Technologies: Microsoft SQL Server, Oracle SQL Data Modeler, Oracle SQL Developer, MySQL Workbench, PyCharm, SQL Server Management Studio (SSMS), MySQL, MariaDB, Python 3, Data Modeling, Jenkins, IntelliJ IDEA, Eclipse, SQL, Scrum, Excel VBA, Database Design, Data Processing Automation, Data Quality Analysis, Customer Relationship Management (CRM), Batch File Processing, NumPy, Pandas, Talend Data Integration, Seaborn, Git, Java 8, JSON, Jira, Confluence, Microsoft Teams, T-SQL (Transact-SQL), Windows PowerShell, Technical Requirements, JavaScript 6, Regular Expressions, Data Engineering, Python, VBScript, Data Wrangling, Data Cleaning, GitHub, Data Migration, Concepting, Architecture, Performance Analysis, Interface Design, Human Interface Design, ANSI SQL, SQL Performance, Performance Optimization, Partitioning, Data-driven Design, Unit Testing, Batch, Business Intelligence (BI), Data Analysis, Data Quality, Process Automation, Reporting, BI Reporting, Clustering, Cluster Analysis, Test Management, REST APIs, Docker, Data Masking, UML, GDPR, Data Protection, TestDirector

Senior IT Consultant (Database Development)

2012 - 2016
IT-P GmbH
  • Developed a proprietary CRM system (operational and analytical) on Oracle 11g DWH. Completed data modeling, planning, requirements analysis, conception, implementation, data migration, process automation, testing, documentation, and second level support.
  • Created and executed campaigns, reports, and their automation and exploitation of potential customers via data mining, analysis, and visualization in the analytical CRM.
  • Delivered PL/SQL processes to improve the data quality of the contact data (addresses, communication data, telephone, and email). Completed with regular expressions via offline address references and the web interface (Google Maps API/addressdoctor API).
  • Improved response rates archived by an intelligent deduplication (batch) process in PL/SQL with post returns handling (various postal deliverers of the EU).
  • Exchanged and integrated various outer sources with PL/SQL to improve the quality of the data and gain more details.
Technologies: Batch File Processing, Oracle SQL Developer, Oracle SQL Data Modeler, Oracle Database, Oracle 11g, Data Modeling, Eclipse, SQL, PL/SQL, Oracle Database Tuning, Scrum, Excel VBA, Microsoft Access, Database Design, Oracle Performance Tuning, Data Processing Automation, Oracle Forms & Reports, Data Quality Analysis, Customer Relationship Management (CRM), Subversion (SVN), JSON, Windows PowerShell, Technical Requirements, ETL, Regular Expressions, XML, Python, Visual Basic for Applications (VBA), VBScript, Data Cleaning, Data Migration, Concepting, Architecture, Oracle PL/SQL, PL/SQL Tuning, Performance Analysis, Interface Design, Human Interface Design, ANSI SQL, SQL Performance, Performance Optimization, Partitioning, Parallel Programming, Software Design Patterns, Designing for Data, Data-driven Design, Object-relational Data Model, Pipelined Table Functions, Bulk Processing, User-defined Data Types (UDT), Unit Testing, OpenWeatherMap, Google Maps API, Batch, Business Intelligence (BI), Data Analysis, Data Quality, Ad Campaigns, Oracle 12c, Oracle Reports, Process Automation, Business Process Automation, BI Reporting, Reporting, Customer Lifecycle, Customer Lifetime Value (CLV), Clustering, Cluster Analysis, K-nearest Neighbors (KNN), Test Management, Market Segmentation, User Intent Scoring, REST APIs, Oracle, Data Warehouse Design, Data Mining, Text Mining, A/B Testing, Classification, In-memory Databases, Data Masking, UML, Data Protection, Data Warehousing, Geofencing & Geotargeting, Geospatial Analytics, Geospatial Data

Project Manager Database Management

2008 - 2012
SAZ GmbH
  • Managed, planned, controlled, and developed operational tasks in PL/SQL for direct marketing campaigns in fundraising marketing. With the help of a six-person project team, we automated the process.
  • Created an RFM donor segmentation process for direct marketing campaigns. Conceived, planned, and controlled the team, and built the SQL scripts and PL/SQL methods. Delivered visualizations in Excel with VBA, set up batch processes, and saw performance improvements in large databases with over three million customers.
  • Delivered donor scoring for direct marketing campaigns using Scrum. Planned and controlled the team. Built the SQL scripts and PL/SQL functions and batch processing. Created performance optimization of large data sets that visualized the donors.
  • Created a campaign management tool, oversaw the project management and conceptual design of the application that was built on an existing data model. Served as product owner using Scrum to organize the project. Implemented SQL and PL/SQL queries and views.
  • Captured requirements and created the conceptual design of an automatic reaction process. Oversaw the database design in 3NF, and delivered SQL and PL/SQL development. Created Excel documents via SQL by XML, migrated the existing legacy data, and performed unit testing.
Technologies: A/B Testing, Oracle Database, Oracle 11g, Data Modeling, SQL, PL/SQL, IT Project Management, Oracle Database Tuning, Excel VBA, Microsoft Access, Database Design, Oracle Performance Tuning, Data Processing Automation, Customer Relationship Management (CRM), Batch File Processing, Subversion (SVN), Technical Requirements, Regular Expressions, XML, Data Migration, Concepting, Agile Software Testing, Product Owner, Architecture, Oracle PL/SQL, MediaWiki, PL/SQL Tuning, Performance Analysis, Interface Design, Human Interface Design, ANSI SQL, SQL Performance, Performance Optimization, Batch, Data Analysis, Process Automation, BI Reporting, Reporting, Customer Lifecycle, Customer Lifetime Value (CLV), Market Segmentation, User Intent Scoring, Oracle, UML, Data Protection

DevOps and Data Back-end Modeling for Automotive Science

Customized a Java-based proprietary application to better fit customer needs. The environments used were up to MySQL 8.0 and MS SQL Server 2019 with Java. The DevOps process is based on Jenkins and batch scripts.

aCRM - Retention Analysis

Delivered cohort analysis of customer data with visualization in Python. Conducted data wrangling and cleaning, retrieved the insides from the data, visualized and grouped customers (cohorts), and analyzed retention.

oCRM - Data Modeling for Address Data Management

Created and validated a data model for German address data management. Tasks included database design and verification of requirements, integration of different data sources, and storage of the data origin.

oCRM - Data Migration File-based Data Management for MariaDB

Acquisition and storage of file-based data storage in a MariaDB database. Regular import via Talent ID, address data, and transactions. Tasks included conceptual design of the import process, administration, and import process creation.

Data Quality Framework (Library)

Created a cross-library in MySQL and Python with functions for data quality (DQ) improvements and analysis of potential improvements. Tasks included the conception, database design, modeling and implementation of methods, data analysis, and test management.

Governmental Administration Software

Migration of the existing software system to improve the data model.
Tasks included the adaptation of the data model and PL/SQL application logic and the creation and maintenance of database tables, views, and triggers. Updated and extended various interfaces with Oracle XML technology, implemented the application and integration tests, and conducted test analysis and data transfers from the previous system (MS Access).

Image Recognition for Product Quality

Image processing to recognize gaps in material for scientific quality checkups. Tasks included developing an Open Document Format (ODF) Python script that recognizes and visualizes thermical changes in the surfaces of different materials based on Imagemagick and the PIL library.

Proprietary CRM System

I implemented a proprietary customer-oriented CRM system for an automotive supplier for European customers, fleet, and franchise businesses. I provided project planning, requirements analysis, concept development, architecture, implementation, data migration, process automation, test management, documentation, and 2nd-level support. I created and executed campaigns and reports about automation, uncovering potential customers via data mining, analysis, and visualization. Improved the data quality of the contact data and intelligent deduplication process. Determined customers' creditworthiness with profitability data, validation, and various customer scoring and segmentation processes. Developed efficient ETL processes, automated existing processes, and implemented process and integration tests. Analyzed test results, set new marketing strategies, created new direct marketing campaigns and implemented these in the automated data management processes. Designed and maintained CRM data in an Oracle data warehouse and built and implemented all CRM-relevant business processes as frameworks in PL/SQL. Delivered analytical models for customer identification.

Medical NGO Administration Software

Migration and improvement of an existing software system in Oracle 11g database. Module wise development and parallel operation of the old system. Adaptation of the data model and the PL/SQL application logic,
creation and maintenance of database tables, views, and all DB objects. Updating and extending various interfaces with Oracle XML technology. Implementation of application, including integration tests, test analyzing, and data transfer from the previous system (MS Access).

oCRM - Response Management

Autonomous reaction management on customer transactions for direct
marketing campaigns in fundraising. Captured requirements and conceptual design of an automatic reaction process. Delivered relational data modeling and database design in compliance with the common forms. Created the business logic and programmed application logic with SQL and PL/SQL. Created and maintained tables, indexes, views, sequences, and triggers. Optimized performance and delivered Excel documents via SQL by generating the XML syntax from an Oracle 11g database. Migrated the data of the existing legacy data and executed integration tests.

oCRM - Campaign Management Tool

Management tool for operational marketing campaigns for fundraising.
Spearheaded the project management and conceptual design of the application, building on an existing data model. Planned and controlled the project using Scrum as product owner (requirement analysis, target concept development, user story development, product backlog determination, monitoring of product development). Implemented SQL and PL/SQL queries and views. Inspected sprints through execution and application tests.

aCRM - Customer Segmentation Process

Increased ROI by creating donor segmentation according to RFM for direct marketing campaigns. Developed the concept for the project, planned, and led the team in the implementation of SQL scripts and PL/SQL methods. Created and maintained tables, views, indexes, sequences, and triggers. Implemented visualization of donors as a matrix in Excel with VBA used for the evaluation and selection of segments. Implemented and integrated scripts in a batch processing system. Spearheaded performance improvements in large databases (more than three million customers and 100 million transactions).

Analytical CRM – Donor Scoring

• Increased ROI by creating donor scoring for direct marketing campaigns.
• Integrated the scoring function in the operational campaign process and delivered the concept development for integration.
• Set project implementation according to Scrum.
• Architectured and mediated the development team.
• Created SQL scripts and PL/SQL functions.
• Integrated functions into a proprietary batch processing system.
• Created tables, views, indexes, sequences, and triggers.
• Oversaw performance optimization over the entire process due to handling large data sets (more than 3 million customers and 110 million transactions).
• Developed a multi-level PL/SQL process for data management and performance optimization.
• Created the visualization of the donors (in Excel with VBA and XML) to evaluate customers.
• Implemented unit tests.

Implemented Drug Approval Process Standard in DMS (Practical Work for Thesis)

Created workflows in the open-source DMS Alfresco to the requirements of the eCTD standard for drug approval. Performed scientific work on eCTD, geriatric care, and the implementation of these in open-source DMS systems. Diploma thesis: "Mapping of complex standards for electronic administration in the areas of drug approval as well as elderly care and nursing in document management systems."
2000 - 2007

Diploma in Business Informatics

University of Rostock - Rostock, Germany

MAY 2021 - PRESENT

Become a Scrum Guru

Udemy

MAY 2021 - PRESENT

Jenkins from Zero to Hero

Udemy

APRIL 2021 - PRESENT

Docker Deep Dive

LinuxAcademy

MARCH 2021 - PRESENT

Machine Learning by Andrew Ng (Stanford University)

Coursera

SEPTEMBER 2020 - PRESENT

AWS Certified Solutions Architect Associate (SAA-C02)

LinuxAcademy

AUGUST 2020 - PRESENT

AWS Certified Cloud Practitioner 2020 (CLF-C01)

LinuxAcademy

JULY 2020 - PRESENT

Python Programmer

DataCamp

JANUARY 2019 - PRESENT

Microsoft: DAT251x – Data Modeling

edX

JULY 2018 - PRESENT

Data Scientist with Python

DataCamp

APRIL 2018 - PRESENT

Intro to Statistics + Descriptive Statistics

Udacity

SEPTEMBER 2014 - PRESENT

Certified Professional Requirements Engineer (CPRE)

IREB

MAY 2014 - PRESENT

ITIL V3 Foundation Examination

Axelos

NOVEMBER 2013 - PRESENT

Oracle Database: SQL Certified Expert

Oracle

Libraries/APIs

NumPy, Pandas, PiLLoW, ImageMagick, OpenWeatherMap, Google Maps API, TensorFlow, PySpark, Scikit-learn, REST APIs, SQLAlchemy

Tools

Oracle SQL Data Modeler, MySQL Workbench, Subversion (SVN), PyCharm, Git, Apache Airflow, GIS, Jenkins, IntelliJ IDEA, Microsoft Access, Seaborn, Jira, Confluence, Microsoft Teams, GitHub, MediaWiki, Oracle Reports, Scikit-image, Erwin, Elastic, Amazon OpenSearch, TestDirector

Languages

SQL, Batch, Python 3, T-SQL (Transact-SQL), XML, Python, VBScript, UML, Excel VBA, Java 8, JavaScript 6, Visual Basic for Applications (VBA)

Platforms

Oracle Database, Oracle, Docker, Eclipse, Software Design Patterns, Amazon Web Services (AWS), Kubernetes, Apache Kafka, Amazon EC2

Paradigms

Database Design, Data-driven Design, Scrum, Business Intelligence (BI), ETL, Interface Design, Human Interface Design, Parallel Programming, Unit Testing

Storage

Oracle SQL Developer, MySQL, Oracle 11g, PL/SQL, Oracle Database Tuning, Oracle PL/SQL, ANSI SQL, SQL Performance, Database Modeling, Oracle 12c, SQL Server Management Studio (SSMS), Microsoft SQL Server, MariaDB, JSON, PostgreSQL, PostGIS, DBeaver, In-memory Databases, ER/Studio Data Architecture, Amazon S3 (AWS S3), Redshift, Data Pipelines

Frameworks

Windows PowerShell, Spark, Alembic

Other

Data Modeling, Oracle Performance Tuning, Data Processing Automation, Data Quality Analysis, Customer Relationship Management (CRM), Batch File Processing, Regular Expressions, Data Wrangling, Data Cleaning, PL/SQL Tuning, Performance Analysis, Performance Optimization, Customer Segmentation, Partitioning, Designing for Data, Pipelined Table Functions, Bulk Processing, User-defined Data Types (UDT), Data Quality, Business Process Automation, Process Automation, Customer Lifecycle, Customer Lifetime Value (CLV), Market Segmentation, Data Engineering, Data Visualization, Data Migration, Concepting, Architecture, Object-relational Data Model, Data Analysis, Ad Campaigns, BI Reporting, Reporting, Clustering, Cluster Analysis, User Intent Scoring, Oracle Database 18c, Amazon RDS, Data Warehouse Design, A/B Testing, Data Masking, Data Protection, Data Warehousing, Geofencing & Geotargeting, Geospatial Data, ITIL V3 Foundation Certified, IT Project Management, Oracle Forms & Reports, Talend Data Integration, Technical Requirements, Product Owner, Agile Software Testing, Scrum Master, K-nearest Neighbors (KNN), Test Management, Data Mining, Text Mining, Classification, Deep Neural Networks, Natural Language Processing (NLP), Machine Learning, Churn Analysis, Image Processing, Statistics, Time Series Analysis, GDPR, Geospatial Analytics, Generative Pre-trained Transformers (GPT), RESTful Microservices, Geographic Information Systems, QGIS, Data Build Tool (dbt), Key Performance Indicators (KPIs)

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