# Databases > Selected Engineer ApS work demonstrating Databases — the achievements that prove it. - [Engineered hourly electricity consumption aggregation pipeline in Python / SQL / Bash + Jq, achieving 180ms for 30‑day datasets across heterogeneous JSONL sources.](https://engineer.company/portfolio/engineered-hourly-electricity-consumption-aggregation-pipeline-in-python-4/) - [Accelerated geographical data pipeline performance by 50x by improving SQL programming and data modeling across PostgreSQL, MS SQL, and Google Cloud BigQuery.](https://engineer.company/portfolio/accelerated-geographical-data-pipeline-performance-by-50x-by-5/) - [Improved geographical map application performance by 10x through strategic database transition from MSSQL to PostgreSQL, optimizing processing and data security.](https://engineer.company/portfolio/improved-geographical-map-application-performance-by-10x-through-6/) - [Resolved 1,000 issues in geographical data and time‑series data, using GDAL, ArcGIS, PostGIS, Mapbox, QGIS, SQL (PL/pgSQL, Transact‑SQL), Bash, ensuring high‑quality big data processing.](https://engineer.company/portfolio/resolved-1-000-issues-in-geographical-data-and-7/) - [Designed, implemented, and administered 6 ETL/ELT pipelines, utilizing Google BigQuery, MSSQL, PostgreSQL, Shell scripting, PL/pgSQL, and Transact‑SQL, integrating data for efficient Python API processing.](https://engineer.company/portfolio/designed-implemented-and-administered-6-etl-elt-pipelines-8/) - [Released 500 electricity and GIS data analysis reports, utilizing deep research and troubleshooting to ensure accurate geographic and time series big data insights.](https://engineer.company/portfolio/released-500-electricity-and-gis-data-analysis-reports-11/) - [Architected, created, and managed 100 PostgreSQL, MS SQL, and Google BigQuery data warehouse databases with primarily GIS and time‑series data, optimizing performance and scalability.](https://engineer.company/portfolio/architected-created-and-managed-100-postgresql-ms-sql-12/) - [Designed, deployed, and maintained 10 PostgreSQL and MS SQL servers on Ubuntu Linux VPS, ensuring optimal server performance and reliability.](https://engineer.company/portfolio/designed-deployed-and-maintained-10-postgresql-and-ms-13/) - [Enhanced data security by implementing 1,000 RBAC rules for developers, application instances, PostgreSQL, MS SQL, and other Linux servers, preventing unauthorized access; documented with Ansible automation.](https://engineer.company/portfolio/enhanced-data-security-by-implementing-1-000-rbac-14/) - [Accelerated PostgreSQL performance by 10x via strategic indexing, partitioning, and query optimization, enhancing database efficiency for user, tenant, geospatial, and time‑series electrical data.](https://engineer.company/portfolio/accelerated-postgresql-performance-by-10x-via-strategic-indexing-15/) - [Automated 100 critical data backups using Barman, Google Cloud, Bash, and Python, ensuring data integrity across databases.](https://engineer.company/portfolio/automated-100-critical-data-backups-using-barman-google-18/) - [Directed full‑stack GIS map development, overseeing PostgreSQL, Mapbox, ReactJS, and NodeJS to deliver an integrated solution.](https://engineer.company/portfolio/directed-full-stack-gis-map-development-overseeing-postgresql-25/) - [Led the development, deployment, and support of over 30 GIS projects, demonstrating expertise in PostgreSQL, Bash, Python, JavaScript, GDAL, ArcGIS, PostGIS, and Mapbox technologies.](https://engineer.company/portfolio/led-the-development-deployment-and-support-of-over-35/) - [Automated data processing tasks using Shell scripting, PL/pgSQL, Python, and Transact‑SQL, increasing productivity and efficiency.](https://engineer.company/portfolio/automated-data-processing-tasks-using-shell-scripting-pl-45/) - [Engineered 600 PL/pgSQL‑based ETL/ELT pipelines to streamline complex data processing workflows across multiple PostgreSQL development and production environments.](https://engineer.company/portfolio/engineered-600-pl-pgsql-based-etl-elt-pipelines-54/) - [Architected a layered maritime platform separating a Next.js PWA frontend, a Go (Huma/Fiber) API, and a PostgreSQL function layer, keeping all business logic in the database.](https://engineer.company/portfolio/architected-a-layered-maritime-platform-separating-a-next-57/) - [Designed a JSON passthrough architecture where PostgreSQL functions return complete JSON forwarded verbatim by the Go API, eliminating intermediate unmarshalling and decoupling the frontend from schema changes.](https://engineer.company/portfolio/designed-a-json-passthrough-architecture-where-postgresql-functions-58/) - [Designed a PostgreSQL function‑first data layer — 1,275 stored functions across 34 schemas — so every read and write goes through a function the database can grant, rather than through a table.](https://engineer.company/portfolio/designed-a-postgresql-function-first-data-layer-across-63/) - [Adopted UUID v7 time‑ordered identifiers (PostgreSQL 18) as entity keys to reduce B‑tree index fragmentation and speed up queries.](https://engineer.company/portfolio/adopted-uuid-v7-time-ordered-identifiers-postgresql-18-64/) - [Implemented a catalogue‑driven deep‑merge for stored JSON preferences, preventing missing‑key crashes as the schema evolves.](https://engineer.company/portfolio/implemented-a-catalogue-driven-deep-merge-for-stored-65/) - [Built the Python vessel‑data scrapers (MarineTraffic, Maritime‑Database) and a repeatable import that seeds the platform's reference data — 184,197 rows, including 698 companies and 56,149 vessels.](https://engineer.company/portfolio/built-a-python-vessel-data-scraper-marinetraffic-maritime-66/) - [Modeled the maritime domain into 348 normalized tables across 34 PostgreSQL schemas — professionals, companies, ships, jobs, reviews and the rest — with SMALLINT lookups and UUID v7 keys.](https://engineer.company/portfolio/modeled-the-maritime-domain-professionals-companies-ships-jobs-67/) - [Configured database backup retention as infrastructure‑as‑code, then audited the recovery position and documented the restore procedure — naming the remaining gaps rather than leaving them to be found during an incident.](https://engineer.company/portfolio/configured-database-backup-retention-as-infrastructure-as-code-72/) - [Hardened the application with nonce‑based CSP, HSTS, SameSite cookies, least‑privilege database roles and server‑side entitlement re‑checks.](https://engineer.company/portfolio/hardened-the-application-with-nonce-based-csp-hsts-77/) - [Set the platform's founding decisions in the weeks after the repository opened in November 2025 — the layering, database‑first data access and the zero‑warnings bar — and they still hold nine months on.](https://engineer.company/portfolio/set-the-platform-s-founding-decisions-in-november-2025-80/) - [Built the payments and entitlements layer — Stripe alongside Apple and Google in‑app purchase — gating the directory, search and export through an 11‑table access model checked on the server.](https://engineer.company/portfolio/built-the-payments-and-entitlements-layer-96/) - [Moved slow work off the request path onto a River job queue — 15 worker modules, 8 scheduled tasks and 20 pg_cron jobs — so a request returns while the work behind it carries on.](https://engineer.company/portfolio/moved-slow-work-onto-a-river-job-queue-97/) - [Kept the schema honest across 1,022 migrations with a CI gate that builds the database both ways — a fresh install, and an install plus every migration — and fails when the two disagree.](https://engineer.company/portfolio/kept-the-schema-honest-across-1022-migrations-99/) - [Built first‑party product analytics in PostgreSQL — 47 functions over partitioned event tables that prune themselves — pseudonymised behind a rotating salt and gated on the visitor's consent.](https://engineer.company/portfolio/built-first-party-product-analytics-in-postgresql-101/) - [Built the loyalty and reputation system — 67 functions over a 31‑table ledger, with leagues, badges and a redemption shop — taking a row lock on the balance to close the double‑spend window.](https://engineer.company/portfolio/built-the-loyalty-and-reputation-system-105/) - [Built the platform's social layer — posts, feed, groups, mentions, a follower graph and an occasions digest — on the same function‑first data layer as the rest of the product.](https://engineer.company/portfolio/built-the-platform-s-social-layer-106/) - [Built the hiring marketplace and the seafarer career workspace — 151 stored functions across 48 tables — covering vacancies, applications, certificates, rank progression and verified sea time.](https://engineer.company/portfolio/built-the-hiring-marketplace-and-career-workspace-107/) - [Generated 495 achievement pages across three languages from a read‑only SQLite export, with the page address authored as data so that correcting a sentence no longer moved the page and broke the link.](https://engineer.company/portfolio/generated-321-achievement-pages-from-a-sqlite-export-132/) - [Built a database‑driven CV, references, portfolio and cover‑letter generator in Python — 41 modules, 10,580 lines — rendering six output formats from one 23‑table SQLite source assembled by a 19‑step idempotent pipeline.](https://engineer.company/portfolio/built-a-database-driven-cv-and-portfolio-generator-144/) - [Held the generator to 981 test cases at a 92% branch‑coverage floor with warnings treated as failures, and asserted idempotence by running the whole build pipeline twice from an empty file and requiring the second pass to change nothing.](https://engineer.company/portfolio/held-the-generator-to-964-tests-and-a-coverage-floor-145/) - [Wrote tests for the checkers themselves after establishing that a checker fed only clean input will one day report clean because it read nothing — planting a misspelling to confirm the spell‑check finds it, and taking an id range from the database rather than from a number in the test.](https://engineer.company/portfolio/wrote-tests-for-the-checkers-themselves-149/)