László Dezső-Masztera, Developer in Budapest, Hungary
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László Dezső-Masztera

Verified Expert  in Engineering

Software Developer

Budapest, Hungary
Toptal Member Since
September 18, 2020

László is a software engineer with two decades of experience. His primary areas of expertise are relational database and data-warehouse design, development and performance optimization with Oracle Database, Microsoft SQL Server, MySQL, PostgreSQL as well as distributed RDBMS as Greenplum. László's secondary areas of interest are back-end development using PHP, C++, .NET.


Generali Group
Oracle PL/SQL, Sybase PowerDesigner, Oracle, SQL, Database Administration (DBA)...
Agilab Ltd.
PL/pgSQL, PostgreSQL, Python 3, FastAPI, Architecture
SQL, One Identity, T-SQL (Transact-SQL), Microsoft SQL Server...




Preferred Environment

PL/pgSQL, T-SQL (Transact-SQL), PL/SQL, MySQL, PostgreSQL, Microsoft SQL Server, Oracle, Linux

The most amazing...

...project I've led was the merchant module of an electronic payment system for a leading Hungarian bank; it was implemented in PL/SQL.

Work Experience

Data Warehouse Consultant

2020 - PRESENT
Generali Group
  • Developed ETL procedures for the corporate data warehouse.
  • Consulted business owners and created business requirement specifications.
  • Analyzed performance issues and provided recommendations on performance improvements.
Technologies: Oracle PL/SQL, Sybase PowerDesigner, Oracle, SQL, Database Administration (DBA), Architecture

REST API/PostgreSQL Developer

2020 - PRESENT
Agilab Ltd.
  • Developed and designed a back-end REST API for an Agile sprint reporting tool built for scrum masters.
  • Consulted customer and aligned specifications to REST API standards.
  • Designed and implemented a back-end PostgreSQL database.
  • Implemented a back-end data exchange from Jira that fetched sprint summary lists.
  • Implemented OAuth2 authentication with Google and Facebook.
Technologies: PL/pgSQL, PostgreSQL, Python 3, FastAPI, Architecture

IAM .NET Consultant

2019 - 2020
  • Supported the company's IAM solution using the OneIdentity IM.
  • Implemented new procedures and adjusted existing ones to meet new expectations.
  • Designed and implemented automated tests using the Intragen Test Accelerator.
Technologies: SQL, One Identity, T-SQL (Transact-SQL), Microsoft SQL Server, Windows PowerShell, Visual Basic .NET (VB.NET)

Database Consultant

2019 - 2019
Self-employment | Freelance Work
  • Analyzed and optimized the performance of an existing ETL solution by migrating data from several Oracle databases to a MySQL front-end database.
  • Implemented query optimization on the Oracle database side to improve ETL performance.
  • Established new ETL procedures using PL/SQL pipeline functions.
Technologies: SQL, Data Warehouse Design, Data Warehousing, Python 3, MySQL, PL/SQL, Oracle SQL, Database Administration (DBA), Architecture

BI Developer

2018 - 2019
Starschema Ltd.
  • Developed custom data warehouse processes using PL/SQL, PL/pgSQL, and ETL tools such as Talend.
  • Migrated an existing 3-tier application to a big data environment using Greenplum.
  • Provided SQL Bootcamp internal training to business analysts.
Technologies: SQL, Amazon Web Services (AWS), Distributed Systems, Data Warehouse Design, Data Warehousing, Greenplum, Talend ETL, Node.js, PostgreSQL, Oracle, PL/pgSQL, PL/SQL

Middleware Architect

2017 - 2018
International Federation of Red Cross and Red Crescent Societes
  • Analyzed inter-application data exchange processes implemented as Microsoft, BizTalk Server applications, and other technologies.
  • Advised on improvements and optimization of ETL processes.
  • Designed new BizTalk applications and implemented interfaces for new solutions.
Technologies: SQL, Data Warehouse Design, Data Warehousing, ETL, Windows PowerShell, REST APIs, Microsoft SQL Server, BizTalk 2013, BizTalk 2010, VB.NET, C#, Architecture

Lead Developer

2010 - 2016
Agilab Courses
  • Designed and developed custom solutions for a G-Technology desktop application using C#.
  • Developed a data migration tool for importing predefined data packages to a utility GIS system using C# and PL/SQL.
  • Built an ETL solution for populating a front-end database for an international publishing company.
Technologies: SQL, PostgreSQL, Technology, PL/SQL Tuning, Oracle PL/SQL, Oracle, PL/SQL, C#, Database Administration (DBA)

Software Development Consultant

2010 - 2010
Capital Systems Ltd.
  • Provided technical expertise on bank operative back-end applications.
  • Implemented a performance analysis of Oracle database and PL/SQL applications and advised on improvements.
  • Designed and developed a Java Swing UI desktop test suite.
Technologies: SQL, Swing, Java, PL/SQL Tuning, Oracle PL/SQL, PL/SQL, Oracle, Database Administration (DBA)

Lead Developer

2003 - 2009
SmartX Ltd.
  • Managed the development of bank operative back-end applications.
  • Analyzed an existing voice (phone) based electronic payment solution and advised on improvements.
  • Designed and implemented the extension of an electronic payment system with POS and VPOS abilities.
Technologies: PL/SQL Tuning, Oracle PL/SQL, PL/SQL, Database Administration (DBA), Architecture

Internet Software Developer

2000 - 2001
Keekaboo Zoftware Ltd.
  • Redesigned Keekaboo’s real postcard sending system over the internet.
  • Designed and implemented the distributed architecture for web servers, database servers, and middleware.
  • Designed and implemented a data exchange microservice over the internet (kind of the ancestor of a REST API).
Technologies: PHP, MySQLi, MySQL, Apache, Linux, LAMP, Architecture

Lead Developer

1999 - 2000
AltuSoft Ltd.
  • Developed an intranet application for a Hungarian oil company using Visual Basic, ActiveX, Internet Explorer, and PL/SQL.
  • Designed and developed an intranet application for the Hungarian department of an international software corporation using Microsoft SQL Server and VB.NET.
  • Created the application design of a process management system for a leading international laboratories company.
Technologies: UML Diagrams, UML, Internet Explorer, ActiveX, Active Server Pages (ASP), PL/SQL, Oracle, T-SQL (Transact-SQL), Microsoft SQL Server, VB.NET, ASP.NET

Merchant Module for a Leading Hungarian Bank

I designed and implemented the merchant module of electronic payment system for a leading Hungarian bank (PL/SQL). The system received POS, VPOS, and voice (phone) authorizations and routed them accordingly to the internal authorization system or payment card company. It charged merchant clients with authorization fees, provided electronic bank statements to merchants, and processed nightly settlement documents from payment card companies.

Data Migration Tool for a Utility GIS System for a Leading Energy Provider in Germany and Europe

For a leading energy provider in Germany and Europe, I designed and implemented a data migration tool for a utility GIS system using PL/SQL and C#. The tool received technical and GIS data about their field objects like conductors, transformators, stations, and substations in predefined format from the customer's contracted data providers. The tool analysed these data ind imported to the utility GIS system based on G-Technology.

ATM Monitoring System Business Logic for a Leading European and Indian ATM Operator

I designed and implemented the business logic of an ATM monitoring system for a leading European and Indian ATM operator using PL/SQL. The system received ATM and other devices status information from the AS/400 system via a file interface, monitored status changes, and alerted ATM operator staff based on customizable rules when necessary.
1990 - 1993

Bachelor's Degree in Information System Programming

Institute of Informatics, College of Finance and Accountancy of Budapest - Budapest, Hungary


Node.js, REST APIs


Toad, Apache, Turbo Pascal, Talend ETL, Sybase PowerDesigner


T-SQL (Transact-SQL), PHP, SQL, PL/pgSQL, C++, Visual Basic .NET (VB.NET), C#, VB.NET, Python, Python 3, Java, Active Server Pages (ASP), UML


PostgreSQL, MySQL, PL/SQL, Oracle SQL, Oracle PL/SQL, DB, Microsoft SQL Server, MySQLi, Database Administration (DBA), Greenplum


Oracle, Linux, Windows, Windows Server, Apache2, LAMP, Internet Explorer, Amazon Web Services (AWS)




Windows PowerShell, Swing, ASP.NET, ActiveX


Data Warehousing, Technology, PL/SQL Tuning, IIS, Data Warehouse Design, Architecture, Data Analysis, One Identity, Apache FOP, BizTalk 2010, BizTalk 2013, UML Diagrams, FastAPI, Distributed Systems

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