Jim O'Hara - SQL Developer / Azure Data Engineer


Tel: 07969 412292                                                                                                                                       Email: jim@jimohara.com  

Profile / Summary

A Microsoft certified  Azure Data Engineer with over 15 years commercial experience using T-SQL and stored procedures to develop and deliver sustainable solutions. Looking for new opportunities to further develop skills in SQL Server, Snowflake and DataOps.


Key Skills

  • SQL / Data Warehouse Development
  • SQL Server Integration Services
  • Data Warehouse Administration
  • Requirements Gathering & Documentation
  • Solution Design and Development 
  • Agile, Scrum and Kanban Methodologies
  • Communication to Non-Technical Audiences
  • Troubleshooting and Critical Problem Solving 


Recent Career Highlights

  • giffgaff required a solution to managing the growing number of SMS abusers using giffgaff SIM cards to send spam texts to thousands of people on a daily basis. Worked closely with the Head of Fraud Detection to identify SMS spammers; defined technical requirements; designed and developed system to identify SMS abusers; implemented new solution which became a major tool for fraud detection. Succeeded in developing a robust system using test driven development to identify SMS spammers which significantly reduced the number of SMS abuser using Giffgaff to harass and spam people with unwanted text messages. 
  • Visa Group required a solution to investigate problems with the Visa transaction processing system. Engaged as Developer to develop SQL server and report configuration for a transaction reporting tool. Gathered business requirements with senior managers; liaised with Business Analysts to develop user stories and reports; supported deployment into test, QA and production phases; ensured transaction reporting tool was fit for purpose; and ensured stringent internal requirements were met. Succeeded in developing transaction reporting tool to promptly identify issues with Visa transactions and enable swift resolution. 

Career History / Assignments

July 2020 to Present: Rosslyn Data Technologies: Data Engineer

Permanent position as a Data Engineer / ETL Developer utilizing Azure SQL Server and SSIS to develop and maintain data pipelines for spend analytics. Created data ingestion and transformation pipelines for a variety of data sources including SAP, Oracle and Sage for clients such as Sony, NBCUniversal Media and Coca-Cola.

Nov 2006 to July 2020: Server Side Events Ltd: Director

I established Server Side Events Ltd to provide clients with a range of data warehouse and SQL development, data warehouse administration, systems migration, reporting solutions implementation and data warehouse consolidation. Over the past 13 years, I have supported leading clients across the telecoms, financial services, technology and local government sectors. Notable Assignments include:


  • giffgaff 06/2018 to 10/2019: Engaged as Data Warehouse Developer to administer/develop SQL Server data warehouse which held all call data records and financial information for the company including 130 data sources and 13m new records daily. Responsible for supporting planning and development for migration to Snowflake and Redshift, developing system to identify SMS abusers and to support fraud detection, and completing a POC of Data Transformation using DBT and Snowflake. Utilised Agile and Kanban development methodologies. Contract extended 4 times.
  • MarketAxess/TRAX 06/2015 to 04/2018: Engaged as SQL Developer to provide large datasets of trade data to major banks to facilitate FCA reporting. This involved creating SSIS packages to facilitate export in different formats, creating daily SSRS reports based on Oracle and SQL Server and writing complex queries against MiFID II trade data. 
  • RCI Financial Services 10/2014 to 05/2015: Engaged as SQL/Data Warehouse Developer to develop and support several data warehouses used by internal users and car dealerships throughout the UK, Slovenia and Morocco. Responsible for managing Click and Decide (v12) including user support, ad hoc query and database development for SQL Server and Sybase, managing complex proprietary ETL processes for multiple environments and delivering a business-critical month end reporting system. 
  • Visa Europe 05/2008 to 07/2014: Engaged as Developer to lead SQL development and report configuration for a major transaction reporting tool used by the operation support desk to investigate problems with the Visa transaction processing system. Worked closely with Business Analysts to create user stories ad support deployment to test, QA and production environment. In addition, managed the end to end development of authentication system for the main extranet using web services, ASP.Net, XML and XSLT. 
  • Siemens Internet Services 08/2007 to 11/2007: Engaged as Team Leader / Developer to oversee the BBC iPlayer development team with ownership for leading a team of 3 Developers, 3 Testers and a Business Analyst. Managed development within strict SLA measures to prevent financial penalties and led deployment of web service code and database updates across 4 networks and 34 servers.


Early Career / Assignments Summary

02/2007 to 06/2007 and 01/2008 to 03/2008: Hampshire County Council: ASP.Net Developer (Contract)

05/2006 to 02/2007: iBuyTV (Auction TV) ASP.Net Developer (Contract)

07/2004 to 05/2006: Music Choice Ltd (Music Broadcaster): Producer (contract)



  • Microsoft Certified Azure Fundamentals: Jan 2020
  • Microsoft Certified Azure Data Engineer Associate: Feb 20
    • DP-200 Implementing an Azure Data Solution (including Azure Synapse and Data Factory)
    • DP-201 Designing an Azure Data Solution
  • Hands On Snowflake - WebUI Essentials: May 2020

Technical Skills

SQL Server 2005, 2008-2012, 6.5-2016; SQL Server Data Tools for Visual Studio; T-SQL; Stored Procedures; SQL Server Integration Services; ETL; Sybase; Oracle; C#; Query Analysis & Optimisation; XML; XSLT; ASP.Net; Visual Studio; Agile; DataVault 2.0; SSIS; SSRS; Git; Snowflake; DBT; Redshift; Visual Cron

Published Articles

Professional Training and Education

  • Snowflake Essentials - Cloud Data Warehouse: Udemy: Oct 2019
  • SSIS Design Patterns for Data Warehousing: Pluralsight: 2015
  • Bachelor of Arts Major in Political Science (GPA 3.6/4.0): University of North Carolina, USA


Personal Information

Address: Twickenham / London / Thames Valley / South East 

Citizenship: US - Indefinite Leave to Remain as Spouse of EU National   

Basic DBS Certificate Issued 31 Jan 2020

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