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Aldo Zelen, BI Reports Developer in Zagreb, Croatia
Aldo Zelen

BI Reports Developer in Zagreb, Croatia

Member since December 20, 2016
Aldo is a DWH/BI expert who works mostly with financial institutions—he has worked at every stage of a DWH/BI project as an ETL developer/architect, BI developer, team lead, and project manager. The primary database that he uses for his DWH/BI work is Oracle. Along with his primary expertise, Aldo is also a proficient Python developer technical writer and has some big data experience.
Aldo is now available for hire



  • SQL, 8 years
  • BI Reports, 8 years
  • Data Warehouse Design, 8 years
  • PL/SQL, 8 years
  • Oracle Warehouse Builder (OWB), 8 years
  • ETL, 8 years
  • Oracle, 8 years
Zagreb, Croatia



Preferred Environment

Oracle, PostgreSQL, Toad, Redshift, Node.js

The most amazing...

...thing I've worked on was a large data warehousing project for the Erste Group. The data warehouse was sourced from multiple local banks.


  • Technical Writer

    2016 - PRESENT
    • Produced several articles regarding data modeling and SQL.
    • Recommended and implemented online SQL academy development.
    Technologies: Vertableo Modeling Tool
  • Senior DWH/BI Architect

    2015 - PRESENT
    Erste Bank
    • Led a team of DWH/BI architects working mostly within the banking sector.
    • Implemented various tax reporting systems (FATCA, CRS).
    • Implemented various ETL automation projects and frameworks.
    • Worked on a high level BI strategy for data governance compliance in banking.
    • Worked on various performance metrics for developers.
    • Supported the business analyses of banking businesses.
    • Worked on a group DWH project (Erste Group in Austria).
    • Acted in a PM role in various small projects.
    Technologies: Oracle, CA PPM, ETL, BI Tools, UML, Power Designer 16.5, PMI
  • Senior Developer

    2014 - 2015
    Erste Bank Croatia
    • Implemented an analytical CRM system in Oracle as a part of the data architecture.
    • Led a small development team.
    • Worked on various automation projects using the ETL tool.
    • Supported controllng and risk business in banking.
    • Created an automated framework for ETL execution.
    Technologies: Oracle, ETL, BI, TCL
  • Senior Consultant

    2011 - 2014
    • Led a small team working with various PL/SQL tasks.
    • Implemented various financial data marts.
    • Worked on Base II implementation in Oracle (risk related).
    • Worked with Cognos as a reporting platform.
    • Developed several pure SQL algorithms for batch executioin.
    Technologies: Oracle, ETL Tools, BI Tools
  • BI Consultant

    2008 - 2011
    • Supported the CDC implementation in Oracle 10g.
    • Supported the Core DWH implementation in Oracle.
    • Implemented various batch scripts in Bash.
    • Performed a score card implementation in Oracle PL/SQL.
    • Implemented various banking DWH data marts.
    Technologies: Oracle, ETL Tool, BI Tools


  • Technical Blog Article (Other amazing things)

    • Technical blog tied to data modeling.
    • This example has advance SQL algorithms for ETL transformation of temporal data.
    • Recommended various improvements on an online SQL academy.

  • PBZ Bank DWH Project (Development)

    • Worked on a large in-house banking DWH project for a major bank in Croatia.
    • Implemented it in Oracle 11g.
    • Participated in every part of the DWH life cycle project from data staging to data presentation.
    • Worked on various data-marts based on Kimball and Inmon methodologies.
    • Actively communicated with business owners of the various processes in the banking industry for a data-mart implementation.

  • Erste Bank DWH Project (Development)

    • Worked on a large banking DWH project implemented in an Oracle 11g database.
    • Participated in every stage of the DWH project from data staging to BI presentation.
    • Worked on software estimation techniques on various large projects in the banking industry.
    • Implemented complex ETL systems.
    • Worked on ETL modeling automation.
    • Led a designer/architecture team for a DWH/BI system.

  • Insite Analytical CRM System Implementation (Development)

    • Implemented an analytical CRM system for a corporate client's banking acquisition.
    • Worked as a PM and technical lead on this project.
    • Orchestrated the implementation of the system.
    • Led a small implementation team.

  • Erste Group Bank Data Warehouse (Development)

    • Worked as an ISA (information systems architect) for a group DWH project on the side of three countries of the Erste banking group.
    • Participated in development of various SDLC processes.
    • Participated in ETL tool selection.


  • Languages

    SQL, Python, PL/pgSQL, JavaScript, C
  • Tools

    Oracle Warehouse Builder (OWB), PowerDesigner, Tableau, AWS SDK, Pentaho Data Integration (Kettle), Microsoft Excel, Abinitio
  • Paradigms

    ETL, ETL Implementation & Design, Serverless Architecture, ITIL, Oracle ODI
  • Platforms

    Oracle, KNIME, Linux, Windows
  • Storage

    PL/SQL, Redshift, PostgreSQL, NoSQL
  • Other

    Project Estimation, Data Warehouse Design, Data Modeling, ITIL V3 Foundation Certified, Data Vaults, BI Reports, PMI, MicroStrategy Visual Insight, Writing, Software Design, Machine Learning, Project Planning, SAS Visual Analytics
  • Frameworks

    Hadoop, The Open Group Architecture Framework (TOGAF), Apache Spark
  • Libraries/APIs



  • Master's degree in Computer Engineering
    2002 - 2008
    Faculty of Electrical Engineering and Computing (FER), University of Zagreb - Zagreb, Croatia
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