Part A — Purpose and Intent | Why this exists | What we are building | Design principles | Part B — Business-Level Description | B.1 How it is used | B.2 What is checked | B.3 What is compared to the previous delivery | B.4 What is produced | Part C — Technical Specification | C.1 Package structure | C.2 Configuration | C.3 File version detection | C.4 Ingestion and whitespace trimming | C.5 Type inference | C.6 Quality checks | C.7 Custom checks | C.8 SQLite schema | C.9 Main entry points | C.10 Error handling | C.11 Dependencies | Part D — Unresolved and Deferred Issues | D.1 Needs design before implementation | D.2 Backlog — agreed | D.3 Known limitations

How it works | Installation | Configuration | Global config — dqcheckr.yml | Per-dataset config — .yml | What is required vs optional | Fixed-width files | CSV files with an unusable header row | The quality checks | Single-snapshot checks (QC series) | Schema contract checks (SC series) | Version comparison checks (CP series) | Type inference | Running a check | Calling individual checks | Custom checks | The snapshot database | Worked example — Star Wars dataset | Error handling | Design principles

Prerequisites | Launching the app | Pointing the app at your project | Windows and OneDrive | First-run setup | Example configuration files | The interface | Status badges | Dataset panel | Setting up a dataset — the 8-step wizard | Step 1 — Dataset identity | Step 2 — File location | Step 3 — Format and structure | CSV files | Fixed-width (FWF) files | Step 4 — Column classification | Step 5 — Column rules | Step 6 — Rule overrides | Step 7 — Custom checks (optional) | Step 8 — Review and save | Running a quality check | Browsing history | Global configuration | Team use via a shared network drive | Learn more

FLOSS | Standards

Introduction to busdater | Examples and explanations | get_fy function | get_boundary function