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Arkadiy Omelchenko, Database Developer in Berlin, Germany
Arkadiy Omelchenko

Database Developer in Berlin, Germany

Member since September 26, 2022
Arkadiy has been a professional freelancer for almost 15 years with experience in data engineering, integration, warehousing, and modeling, particularly with the entity-relationship model (ER), multi-dimensional, and data vault modeling. He’s also keen on data vault, ETL, ELT, databases, agile application development, object-oriented programming (OOP), software development, and reporting. Arkadiy is a seasoned Java, SQL, Python, Linux, and Talend tools professional.
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Portfolio

Experience

Location

Berlin, Germany

Availability

Part-time

Preferred Environment

Linux, Python, Java, ETL, ELT, SQL

The most amazing...

...project I've done is the automation of data transformation steps for selected transactional data loads for an international Fortune 500 company.

Employment

  • IT Consultant

    2021 - 2022
    An International Fortune 500 Company
    • Supported the data migration for a global food and pharmaceutical client.
    • Automated the data transformation steps for selected transactional data loads, primarily SAP finance and inventory.
    • Created the reporting for the quality assurance of the migrated data.
    Technologies: Talend Cloud Integration, Java, JUnit, log4j, Visual Studio Code, Snowflake, SQL, Excel 365, Apache POI, SQLite, SAP, SFTP, Amazon S3 (AWS S3), SharePoint 365, Microsoft Power BI, Data Engineering

  • IT Consultant

    2019 - 2021
    DB Vertrieb
    • Analyzed the data for the internal VDV-KA standard (PKM).
    • Built the ETL processes for migrating the existing data from multiple data sources into one database.
    • Consulted the conception of the new ETL environment.
    • Exchanged with the developers on PKM standards and implemented the product modules.
    • Assured the quality of the data during the migration.
    Technologies: Talend Open Studio for Big Data, Java, JUnit, log4j, Ant, Eclipse, Eclipse Modeling Framework (EMF), Data Warehousing, SQLite, H2, Microsoft Access, PostgreSQL, PL/pgSQL, Excel 365, Jira, Git, GitLab CI/CD, Artifactory, OpenShift, Python, Pandas, NumPy, Matplotlib, Seaborn, Jupyter, Scrum, Data Vaults

  • IT Consultant

    2019 - 2019
    Unitymedia
    • Developed the new data transfers and optimized and unified the existing scripts and workflows.
    • Analyzed the customers' requirements, built the concepts, and wrote the specifications.
    • Automated the ETL processes for the internal system's communication.
    Technologies: Talend Open Studio for Big Data, Java, JUnit, log4j, Ant, Eclipse, Excel 2010, Jira, Git, GitLab CI/CD, Oracle, Oracle PL/SQL, RESTful Services, JSON, Python, Pandas, NumPy, Matplotlib, Seaborn, Jupyter, Scrum

  • IT Consultant

    2017 - 2019
    An Insurance Company
    • Specified, implemented, and deployed the existing and new ETL processes for data import and export.
    • Implemented database functions and stored procedures to automate the reporting.
    • Consulted the extension of the existing data platform.
    Technologies: Talend Open Studio, ETL, Java, JUnit, log4j, Apache Velocity, Python, Data Build Tool (dbt), Apache Airflow, PostgreSQL, Pandas, NumPy, Matplotlib, Seaborn, Jupyter, Apache POI, IBM Db2, SQL, Stored Procedure, System i Navigator, Subversion (SVN), Git, GitLab, Eclipse, Jira, Confluence, XML, XSD, Excel 2010, Microsoft Power BI, Linux, Bash, Crontab, Mutt, SFTP, Kanban

  • IT Consultant

    2016 - 2017
    Commerz Finanz GmbH
    • Implemented internal banking projects, including Smart, React, and Heaven.
    • Specified and developed the data pipelines for the bank's regulatory reporting.
    • Extracted the data from multiple data sources, including the SAP, CRM, and call center systems.
    • Provided production support, performance tuning, Talend ETL consulting, and ETL data modeling.
    Technologies: Information Systems, Talend Data Integration, ETL, Data Warehousing, Business Intelligence (BI), Java, Spring, RESTful Services, JSON, JUnit, Apache Velocity, XML, XSD, Oracle, Oracle PL/SQL, PostgreSQL, Subversion (SVN), Eclipse, Jira, Confluence, Pentaho Data Integration (Kettle), Scrum, Data Vaults

  • IT Consultant

    2014 - 2015
    An Insurance Company
    • Specified, implemented, and deployed the existing and new ETL processes for data import and export.
    • Implemented database functions and stored procedures to automate the reporting.
    • Consulted the extension of the existing data platform.
    Technologies: Talend Open Studio, ETL, Java, JUnit, log4j, Apache Velocity, Apache POI, IBM Db2, SQL, Stored Procedure, System i Navigator, Subversion (SVN), Git, Eclipse, Jira, Confluence, XML, XSD, Excel 2010, Linux, Bash, Crontab, Mutt, SFTP, Kanban

  • IT Consultant

    2013 - 2014
    VHV Gruppe
    • Implemented the data warehouse project called Ertragsorientierters Schadenmanagement (ESM).
    • Specified and developed data pipelines for the BI solution needed by the controlling.
    • Created the data analysis charts and dashboards with BIRT.
    Technologies: Talend Data Quality, ETL, Java, IBM Db2, SQL, Essbase, Subversion (SVN), Eclipse, HP Quality Center (QC), Data Warehousing, Business Intelligence (BI), BIRT

  • IT Consultant

    2012 - 2013
    Commerz Finanz GmbH
    • Implemented internal banking projects, including Smart, React, Heaven, SEPA, and Dialer.
    • Consulted by the introduction of the new data integration platform.
    • Specified and developed the data pipelines for the bank's regulatory reporting.
    • Extracted the data from multiple data sources, including the SAP, CRM, and call center systems.
    • Provided production support, performance tuning, Talend ETL consulting, and ETL data modeling.
    Technologies: Information Systems, Talend Data Integration, ETL, Java, Spring, RESTful Services, JSON, JUnit, Apache Velocity, XML, XSD, Oracle, Oracle PL/SQL, PostgreSQL, Subversion (SVN), Eclipse, Jira, Confluence, Pentaho Data Integration (Kettle), Scrum

  • IT Consultant

    2010 - 2012
    Landesbank Berlin
    • Developed and deployed the data pipelines for the data migration of the banking system software.
    • Monitored the success of the data delivery at the migration phase.
    • Tracked and fixed bugs in the ETL jobs using HP Quality Center (QC) as a reporting tool.
    Technologies: Talend Data Integration, Talend ESB, Sopera, ETL, SOAP, SoapUI, Web Services, RESTful Services, JSON, Java, JUnit, SQL, Subversion (SVN), Eclipse, HP Quality Center (QC), XML, XSD, Frameworks, OSPlus, DynS

  • IT Consultant

    2007 - 2011
    excentos Software
    • Implemented, coordinated, and deployed the automated load ETL processes for a web application in the context of online product recommendation solutions.
    • Programmed the web application for the online product recommendation.
    • Tracked and fixed bugs in ETL jobs and web applications using Track as a reporting tool.
    Technologies: Java, JavaScript, JSP, JSF, HTML, CSS, SQL, Ant, Maven, JUnit, CruiseControl, Hibernate, Apache Tomcat, log4j, Spring, ETL, Talend Open Studio, Grails, PostgreSQL, Oracle, Oracle PL/SQL, SQLite, Microsoft SQL Server, Transact-SQL, Microsoft Access

Experience

  • Complex ETL Jobs for SAP Migration

    I created complex ETL jobs with Talend Data Fabric and Java, supporting the migration of a global food and pharmaceutical client.

    The data was stored in the cloud with Amazon S3 (AWS S3) and Snowflake data warehouse. The quality of the migrated information was assured with Microsoft Power BI charts and dashboards, automatically updated by the additional logic in the ETL jobs.

Skills

  • Languages

    Python, Java, SQL, Java SE 8, JavaScript, HTML, CSS, Transact-SQL, XML, XSD, Stored Procedure, Bash, PL/pgSQL, Snowflake, Java 8

  • Paradigms

    ETL, Object-oriented Programming (OOP), Scrum, Business Intelligence (BI), Kanban, App Development

  • Platforms

    Linux, Oracle, Eclipse, BIRT, OpenShift, Visual Studio Code, SharePoint 365, Unix, Desktop

  • Storage

    Databases, PostgreSQL, Oracle PL/SQL, SQLite, Microsoft SQL Server, JSON, IBM Db2, Essbase, H2, Amazon S3 (AWS S3), Linux File Systems

  • Other

    ELT, Algorithms, Data Vaults, Data Engineering, GUI Development, Network Programming, Python Enhancement Proposals, Computer Programming, Lambda Functions, GNU, File Systems, Linux Capacity Planning, Linux Kernel, Linux System Maintenance, Domain Name System (DNS), Web Services, File Sharing, Client Management, Email, Shell Scripting, Linux Administration, Linux Network Stack, Ant, CruiseControl, log4j, Talend Open Studio, Talend ESB, Sopera, SOAP, RESTful Services, Frameworks, OSPlus, DynS, Information Systems, Talend Data Integration, Talend Data Quality, Data Warehousing, Crontab, Mutt, SFTP, Data Build Tool (dbt), Talend Open Studio for Big Data, Excel 365, Talend Cloud Integration, SAP, Meltano, SDKs, Singer ETL, PIP, Pipx, Poetry, Cryptography, Systems, APIs, Linux Applications, Network Configuration, System Architecture, Vulnerability Assessment, Linux Device Driver

  • Frameworks

    JSP, JSF, JUnit, Hibernate, Spring, Grails, Apache Velocity, Eclipse Modeling Framework (EMF)

  • Libraries/APIs

    Apache POI, Pandas, NumPy, Matplotlib

  • Tools

    JDK 8, Maven, Apache Tomcat, Microsoft Access, SoapUI, Subversion (SVN), HP Quality Center (QC), Jira, Confluence, Pentaho Data Integration (Kettle), System i Navigator, Git, Excel 2010, Apache Airflow, Seaborn, Jupyter, GitLab, Microsoft Power BI, GitLab CI/CD, Artifactory, GitHub

  • Industry Expertise

    IT Security, Network Security, Security

Education

  • Graduate Degree in Computer Science
    2000 - 2007
    Free University of Berlin - Berlin, Germany

Certifications

  • Certified Professional in Python Programming 1 (PCPP1)
    SEPTEMBER 2022 - PRESENT
    Python Institute
  • Certified Data Vault 2.0 Practitioner (CDVP2)
    MAY 2022 - PRESENT
    DataVaultAlliance
  • Enterprise Professional Security (LPIC-3)
    OCTOBER 2020 - OCTOBER 2025
    LPI
  • Certified Associate in Python Programming (PCAP)
    JUNE 2020 - PRESENT
    Python Institute
  • Linux Engineer (LPIC-2)
    JUNE 2018 - OCTOBER 2025
    LPI
  • Linux Administrator (LPIC-1)
    NOVEMBER 2017 - OCTOBER 2025
    LPI
  • Oracle Certified Associate (OCA) | Java SE 8 Programmer
    APRIL 2017 - PRESENT
    Oracle

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