
Marek Rozenbajger
ETL Development Developer
Marek has spent his professional life with databases. He boarded the big data ship three years ago. Marek now focuses on modeling and designing data lakehouses on Microsoft Cloud platforms: Azure Databricks, ADLS, and ADF. Throughout his 16-year career, he has worked as a data architect, senior consultant, and programmer. He has worked for UBS, Nordea, BP, Honda, and Motorola, among others. Marek has over a decade of experience working in distributed teams.
Portfolio
Experience
SQL - 17 yearsDatabase Modeling - 17 yearsT-SQL (Transact-SQL) - 16 yearsData Modeling - 13 yearsData Warehousing - 13 yearsETL Development - 13 yearsData Warehouse Design - 9 yearsData Lake Design - 3 yearsAvailability
Preferred Environment
Git, Visual Studio, Windows Server, Microsoft SQL Server
The most amazing...
...thing I've designed was a data lakehouse with 30 bitemporal, slow-changing dimensions and late-arriving facts of different granularity with M2M relationships.
Work Experience
Data Engineer
Fincent Inc
- Designed a complete data platform, including the dimensional model, data lake, orchestration, and ELT pipelines. Used Postgres, Apache Airflow, S3, and Python for the tech stack.
- Provided architectural documentation of the solution with guidelines for usage and future extensions.
- Performed the MVP implementation of the data platform. Used MWAA for orchestrating ELT, RDS for metadata database, and S3 for storage.
Senior BI Consultant | Data Architect
UBS
- Designed serverless architecture for Azure data lakehouse with Power BI, Azure Databricks, Azure Functions, ADLS Gen2, and Azure Data Factory. Used Spark SQL, Python, and PowerShell programming.
- Provided data modeling and profiling activities for projects and created visual models of data flows and interactions with UML, DFD, and ERD.
- Designed and implemented state machine-based orchestration for the data lake.
- Supported and extended Microsoft SQL Server data warehouses.
- Created end-to-end CI/CD automation for Microsoft SQL server data warehouse.
Database Consultant
Honda
- Reverse engineered a legacy Microsoft Access-based ERP system; no source code was available.
- Designed a new solution that improved on the original. The application consisted of Windows Forms UI, relational database, and reports' components.
- Went through complete SDLC cycle: implemented the design, tested, and released it. The client was pleased and requested several new features to be added as a separate project.
Database Consultant
The Dominion Group
- Created a custom add-in for Excel 2010 and above. The add-in provides a set of functions that pull data from remote PostgreSQL instances over the Internet.
- Tested the product with different Microsoft Office versions: 2010, 2016, 2019, 365.
- Prepared documentation: PDF and user training videos.
- Answered users' queries and provided support for the application.
Software Developer
Motorola Solutions
- Worked with the key stakeholder on clarifying and documenting the requirements.
- Designed the solution for a sophisticated near-real-time directory change monitoring service.
- Prepared the documentation and provided support for service rollout.
Database Consultant
Nordea Group
- Carried out an audit of a bespoke database system.
- Implemented a feasibility study of new requirements and risk analysis.
- Provided a review of the system to the management of the project.
Data Architect | Solution Architect
BP p.l.c.
- Designed and had a key role in the implementation of a data warehouse. Its purpose was to improve financial efficiency by providing reports and data for analysis.
- Created and implemented the system architecture, database back-end, and ETL and WCF API design.
- Developed the modeling process which concentrated on UML (use case, class, sequence diagrams) as well as data flow, and entity-relationship diagrams.
- Built a database component that involved advanced programming features of Microsoft SQL Server such as CLR integration, distributed transactions, and XML processing.
- Designed and managed the implementation of a self-service intranet site for managing IT services (such as mailboxes, user accounts, distribution lists, and VPN tokens) for 80,000 employees. The purpose of the site was to support the ITIL processes.
- Designed and implemented the system architecture, database design, integration with external systems (LDAP, SOAP web services, REST web services, ODBC), WCF API of the back-end component, and long-running workflows.
- Built a system using Windows Server 2008 R2 Standard, WCF SOAP web services, and an active directory with Kerberos authentication, IIS AppFabric 1.1, and C#.NET 4.0.
- Prepared implementation documentation for the client.
- Liaised with the client's technical authorities and infrastructure managers.
Database Administratior | SQL Developer
BP p.l.c.
- Migrated a reporting platform from the Microsoft SQL Server 2000 to the 2005 version and later to 2008 R2.
- Designed and implemented new data feeds into the reporting system.
- Designed new reports for mid-level managers and enriched the existing ones with additional data.
- Maintained and adapted the system to new requirements and a changing environment.
Microsoft Access Database Developer
Ideal Shopping Direct
- Developed applications for stock control, EDI, work time and performance monitoring with Microsoft Access (VBA) and Microsoft SQL Server (backend).
- Created reports from the collected data with Microsoft Access and Excel (automatic generation of spreadsheets from VBA code).
- Improved several manual processes with the help of self-developed applications.
Experience
Sample Data Warehouse Snowflake Schema ERD
Sample 3NF Entity Relationship Diagram
Sample Data Dictionary
Skills
Languages
T-SQL (Transact-SQL), SQL, UML, C#, Python 3, MDX, Visual Basic for Applications (VBA), Visual Basic .NET (VB.NET), Python, Visual Basic, Excel VBA
Tools
Microsoft Access, Microsoft Excel, SSAS, Spark SQL, Apache Airflow, Microsoft Visual Studio, GitHub, Git, Microsoft Power BI, SQL Server BI
Paradigms
Database Design, Object-oriented Design (OOD), Object-relational Mapping (ORM), ETL, Business Intelligence (BI), Kimball Methodology, Continuous Integration (CI), OLAP
Storage
Microsoft SQL Server, Database Modeling, Relational Databases, SQL Server Data Tools (SSDT), SQL Server 2008, SQL Server Reporting Services (SSRS), Data Pipelines, Database Architecture, RDBMS, Databases, SQL Server 2016, SQL Stored Procedures, Database Structure, Database Transactions, SQLite, PostgreSQL, Database Administration (DBA), Azure Active Directory, SQL Server 2012, SQL CLR, JSON, Data Lake Design, SQL Server Integration Services (SSIS), Data Lakes, SQL Server DBA
Other
Data Engineering, Data Warehousing, Data Modeling, ETL Development, ETL Tools, Data Reporting, Data Architecture, Data Wrangling, Normalization, Transactional Data, Kerberos, LDAP, OData, Azure Data Factory, Data Analysis, BI Reporting, Reports, Data Warehouse Design, Sparx Enterprise Architecture, SOAP, Big Data Architecture, Azure Databricks, Bitemporality, ELT, Azure Data Lake, Big Data, Amazon RDS, System Administration, Consulting, Data Management, Data Visualization, Database Optimization
Frameworks
Windows PowerShell, .NET, Spark
Libraries/APIs
ODBC, SQLite.NET, PySpark, Windows Forms (WinForms), REST APIs, Pandas
Platforms
Windows Server, Windows Server 2008, Windows Server 2012, Databricks, Azure, Azure Functions, Amazon Web Services (AWS), Oracle
Education
Bachelor's Degree in Computer Science
The School of Banking and Management in Kraków - Kraków, Poland
Certifications
MCP: Windows Server
Microsoft
MCTS: SQL Server 2008
Microsoft
ITIL Foundation
Asseco Data Systems