SQLAlchemy 2.0 Cheatsheets (DB-Agnostic)

Cheatsheets for SQLAlchemy 2.0 (DB-agnostic). Pair with the textbook . For Postgres-specific, see the Postgres cheatsheets .

SQLAlchemy Cheatsheet 11 — Events and Hooks

Cheatsheet: engine events (connect/checkout/before_cursor_execute), session events (before_commit), mapper hooks (before_insert/update/delete), attribute events.

SQLAlchemy Cheatsheet 12 — Repository and Unit-of-Work Pattern

Cheatsheet: repository classes, unit-of-work, generic base repo, service-layer separation.

SQLAlchemy Cheatsheet 13 — Soft Delete, Audit, and Timestamps

Cheatsheet: SoftDeleteMixin, auto-timestamps via events, audit log table, with_loader_criteria for transparent filtering.

SQLAlchemy Cheatsheet 14 — Multi-Tenancy Patterns

Cheatsheet: shared DB + tenant_id, schema-per-tenant, DB-per-tenant, query filters, context propagation.

SQLAlchemy Cheatsheet 15 — Common Pitfalls and Fixes

Cheatsheet: N+1, IntegrityError, DetachedInstanceError, MissingGreenlet, lazy-load in async, pool exhaustion.

SQLAlchemy Cheatsheet 16 — Type Annotations and Mapped Style

Cheatsheet: Mapped types, mapped_column with types, type_annotation_map, Annotated types, generic mapping.

SQLAlchemy Cheatsheet 17 — Inheritance and Polymorphism

Cheatsheet: single-table inheritance, joined-table inheritance, concrete inheritance, polymorphic loading, with_polymorphic.

SQLAlchemy Cheatsheet 18 — Hybrid Properties, Computed Columns, and Aggregates

Cheatsheet: when to use hybrid_property vs column_property vs Computed, with FastAPI integration.

SQLAlchemy Cheatsheet 19 — Change Feeds, Outbox, and Logical Replication

Cheatsheet: outbox emit on commit, CDC via Debezium, logical replication, SKIP LOCKED worker pattern.

SQLAlchemy Cheatsheet 20 — Recipes (Pagination, Filtering, Sorting, Bulk)

Cheatsheet: cursor pagination, filter from Pydantic, sort safelist, bulk upsert, COPY-fast loads.