Theresa K Bell, Developer in San Jose, CA, United States
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Theresa K Bell

Verified Expert  in Engineering

Database Engineer and Developer

San Jose, CA, United States
Toptal Member Since
May 23, 2024

Theresa is a highly motivated senior data engineer with 20+ years of experience architecting and delivering data-driven solutions across various industries. She is an expert SQL writer and optimizer with a proven ability to leverage SQL, ETL/ELT pipelines, and data warehousing expertise to transform raw data into actionable insights for key stakeholders. With exceptional skills in writing codes in C, C#, VB.NET, VBScript, ASP.NET, and Python, Theresa will be a great addition to any team.



Preferred Environment

SQL Server Integration Services (SSIS), Python 3, Microsoft SQL Server, Oracle, PostgreSQL, MySQL, Visual Studio

The most amazing...

...thing I've done is improve VeriFone's call center service level performance by architecting the call center data warehouse and KPI dashboards.

Work Experience

Staff Software Engineer

2018 - 2023
  • Architected call center raw data warehouse and KPI dashboards in Tableau, increasing a call center service level by 10%. Designed and developed ELT pipelines. Used complex SQL queries to transform data into actionable insights.
  • Spearheaded a team that automated the purchase order commitment and forecast process for contract manufacturers, enhancing workflow efficacy and data precision, reducing manual processes, and streamlining communication.
  • Enhanced accuracy and performance of the legacy repair global operations dashboard, overhauled the data repository for better scalability, constructed ELT pipelines, and wrote optimized SQL queries to ensure data reliability.
  • Led the automation of components demand forecasting, reducing manual effort and improving forecast accuracy. Identified data sources, designed the warehouse, and worked with stakeholders to derive forecasting algorithms.
  • Established a standardized repair quality data warehouse for consistent and reliable data collection from 3rd-party repair centers. Collaborated with repair center teams to define data requirements and ensure data integrity.
  • Contributed to creating a global direct-to-merchant (DTM) KPI dashboard, analyzing market data, and developing ETL processes in SQL Server Integration Services (SSIS) to extract KPIs for data-driven decision-making.
Technologies: SQL, Pipelines, ELT, ETL, Data Warehousing, Tableau

VeriFone Call Center KPI Dashboard and Executive Summary Reports

Collaborated with executives and stakeholders to identify KPI metrics. I designed and architected the data warehouse and ELT pipelines to extract data from multiple sources. I also wrote optimized SQL queries to transform data and upload it to a reporting repository. Finally, I generated the KPI scorecard dashboard and executive summary reports using Tableau.
1980 - 1986

Bachelor's Degree in Engineering

Feati University - Manila, Philippines


Azure for Data Engineering



Visual Studio, Tableau


SQL, VB.NET, Python 3, C#




SQL Server Integration Services (SSIS), Microsoft SQL Server, PostgreSQL, MySQL, Azure SQL




Programming, Pipelines, Data Warehousing, ELT

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