Bartłomiej Osak

Bartłomiej Osak

Joined on: 2019-05-26
Wola Kopcowa, Poland
SKILLS: bootstrapcsshtmlhtml5javajava eelaravellinuxMongoDBMSSQLmysqloraclephpRESTsqlSQLite

I'm an IT engineer by profession. Currently I study daily at the second degree of IT studies. My main skills are:

  • Designing relational and non-relational databases (Oracle, Microsoft SQL Server, MySQL, SQLite, H2, MongoDB, Microsoft Azure, etc.)
  • Designing the Business Intelligence layer:
    • Designing the integration layer (ETL processes) based on Microsoft SQL Integration Services
    • Designing the analysis layer based on Microsoft SQL Analysis Services (multidimensional cubes or a tabular model)
    • Designing the reporting layer based on Microsoft Power BI (dynamic reports) and Microsoft SQL Reporting Services
  • Create any SQL queries for each relational database
  • Creating procedures, functions, triggers and dynamic SQL in T-SQL and PL / SQL
  • Creating websites (HTML, CSS, Bootstrap)
  • Creating CMS class systems (PHP5 / 7, Laravel framework, frontend: HTML, CSS, Bootstrap) I also offer coding in Java using JSP, Servlets (EE), Spring MVC (beginner level).

System do analiz działalności przedsiębiorstwa budowlanego

General description:

The work presents a project with the implementation of a data warehouse and individual layers of a multidimensional model, ie data integration, analysis, and reporting and visualization. The presented solution is intended for analyzes for a construction company. Generated analyzes and reports can be the basis for supporting decisions on current and future sales and purchasing processes. To implement the data warehouse with the business analytics layers, the Microsoft SQL Server 2017 database in the Developer version and the data warehouse and data warehouse mechanisms included in it were used. The data used in the work has been imported from the company's accounting files and reflects the actual sales and purchase data.

Technologies and services used:

  • Microsoft SQL Server 2017 Developer
  • Microsoft SQL Server Integration Services (SSIS)
  • Microsoft SQL Server Analysis Services (SSAS - Multidimensional Model & Tabular Model)
  • Microsoft Power BI
  • T-SQL
  • DAX
  • MDX
  • Microsoft Excel PowerPivot

Implemented solutions:

  • ERD project for data warehouse - constellation diagram
  • ETL process using SSIS
  • OLAP multidimensional model using SSAS
  • a tabular model using SSAS
  • reporting and visualization using Power BI
  • data mining using SSAS algorithms (Microsoft Association Rules, Microsoft Naive Bayes, Microsoft Clustering)
  • testing of implemented solutions
  • Technical Documentation

The work contains implementations in the fields of:

  • Business Intelligence
  • Data Analysis
  • ERP
  • Data warehouse download:

System wspomagający zarządzanie dyspozytornią przedsiębiorstwa komunikacji miejskiej

A system design streamlining the work of the dispatch office and all organizational units associated with it.

Used technologies:

  • Laravel 5.6
  • PHP 7.2.5
  • MySQL 5.7.21
  • AJAX
  • JavaScript
  • JQuerry
  • Bootstrap 4 download:


The project includes an example data warehouse built on the basis of a snowflake scheme. The theme is "Shoe and leathercraft workshop".

The following analytical queries were written in the project:

  • 2 ROLLUP queries
  • 2 CUBE queries
  • 2 GROUPING SETS inquiries
  • 2 calculation partitions (PARTITION BY)
  • 3 movable windows (application: LEAD, LAG, FIRST_VALUE, LAST_VALUE, etc.)
  • 3 rankings (application: RANK () and DENSE_RANK ()) All queries were written to provide in-depth analyzes for market analysts or economists.

The project was written based on the Oracle Database 11g Express Edition.

Used technologies:

  • HTML 5.0
  • CSS 3.0
  • jQuery
  • JavaScript In addition, an own intelligent data generator has been written for correct analyzes in Java SE in accordance with the object paradigm.

In order to easily create data warehouse tables and delete them, a special client application was written in the recursive version using SQL * Plus. download:

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