Krzysztof Ł.

Data Engineer

Krzysztof is a seasoned Data Engineer with 16 years of expertise in ETL processes, database development, and system optimization. Skilled in PL/SQL, Snowflake, and Oracle, he has successfully led teams, optimized database performance, and managed complex system migrations within agile environments, including Scrum.

At Fiserv, he developed and maintained Oracle systems for card transactions, implemented ETL processes, and played a key role in leading Scrum meetings. At mBank, he supported the Impairment system, optimized critical procedures, and served as a Scrum Master. Additionally, he led a major migration project at QuadGraphics, transitioning systems from Sybase to Oracle.

With a strong technical foundation and leadership experience, Krzysztof excels in designing efficient, scalable data solutions that drive business success.

Main expertise

  • SQL
    SQL 16 years
  • Oracle
    Oracle 11 years
  • Sybase IQ
    Sybase IQ 7 years

Other skills

  • Team Leading 3 years
  • Jenkins
    Jenkins 2 years
  • Informatica
    Informatica 1 years
Krzysztof

Krzysztof Ł.

Poland

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Selected experience

Employment

  • Senior ETL / Database Developer

    Fiserv S.A. - 4 years

    Project description: Maintenance and development of Oracle database systems through ETL processes for debit and credit card transactions/authorizations. Managed multiple teams comprising over 20 people, following the Scrum methodology.

    Responsibilities:

    • Developing Oracle databases;

    • Implementing ETL processes in Oracle Data Integrator (ODI);

    • Performance tuning of SQL statements;

    • Preparing production deployments and implementation plans;

    • Assisting other team members and onboarding new employees;

    • Assisting the Scrum master and leading some Scrum meetings.

    Technologies used: Oracle 19, GIT, Gerrit, Jenkins Flyway, Oracle Data Integrator, Snowflake, JIRA, Confluence, Microsoft Teams.

    Technologies:

    • Technologies:
    • Oracle Oracle
    • PL/SQL PL/SQL
    • Unix Unix
  • Oracle PL/SQL Developer

    mBank S.A. - 1 year 1 month

    Project description: Provided support for the Impairment system as part of a scrum team of 9 people. Followed the Scrum methodology.

    Responsibilities:

    • Developing Oracle databases;

    • Acting as Scrum master from 2021-02-01;

    • Implementing ETL processes in Informatica Power Center based on SAS processes;

    • Collaborating with the business to fulfill task requirements;

    • Documenting system functionalities;

    • Conducting unit testing of database objects (packages, procedures);

    • Creating code reviews for applied changes;

    • Reviewing other developers' changes;

    • Managing and using Git repository;

    • Optimizing Oracle procedures.

    Technologies used: Oracle 12, GIT, Bitbucket, Informatica Power Center, JIRA, Wiki, Microsoft Teams.

    Technologies:

    • Technologies:
    • Oracle Oracle
    • Informatica Informatica
    • PL/SQL PL/SQL
  • Scrum Master/Senior Database Developer

    QuadGraphics US/Poland - 3 years 9 months

    Migration from Sybase to Oracle 12c. Led a database team in a project involving 30 people across 3 development teams. Applied the Scrum methodology.

    Responsibilities:

    • Acting as Scrum Master and Team Leader for the database team;

    • Providing technical leadership to all developers in the database area;

    • Supporting the Product Owner in Sprint planning and monitoring progress;

    • Analyzing differences between Sybase T-SQL and Oracle 12c PL/SQL and implementing necessary changes;

    • Converting triggers to compound triggers Conducting unit testing of database objects (views, triggers, procedures);

    • Creating code reviews for applied changes Reviewing other developers' changes;

    • Managing the SQL team;

    • Managing and using SVN repository.

    • Optimizing Oracle procedures;

    Technologies used: Oracle 12c, Sybase, SVN, Crucible, Unix, Agile Kanban, Azure Boards, Azure Queries and Charts, Microsoft Teams.

    Technologies:

    • Technologies:
    • Oracle Oracle
    • Sybase IQ Sybase IQ
    • PL/SQL PL/SQL
  • MS/SQL Developer

    Polkomtel S.A. - 5 months

    • Implemented new business logic in MS/SQL 2008 database as part of a fixed-price project.

    Responsibilities:

    • Analyzing project requirements and specifications Implementing database changes, including designing the database structure and developing tables and stored procedures;

    • Conducting unit testing of developed changes Using Git repository.

  • Oracle Database Consultant

    First Data Polska - 3 months

    • Responsible for the maintenance of debit and credit card systems in an Oracle 11 database.

    Responsibilities:

    • Analyzing business and fix change requests (Jira requests);

    • Implementing changes in Oracle views, packages, triggers, and database links Using SVN repository.

    Technologies:

    • Technologies:
    • Oracle Oracle
    • PL/SQL PL/SQL

Education

  • BSc.Computer Science

    Warsaw University of Technology (Politechnika Warszawska) · 2002 - 2007

Portfolio

  • porfolio-0

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