schema

name	schema
description	数据库模式设计、迁移规划、索引策略和关系建模。
zh_description	数据库模式设计、迁移规划、索引策略和关系建模。
version	1.0.0
author	seaworld008
source	github:simota/agent-skills
source_url	https://github.com/simota/agent-skills/tree/main/schema
license	MIT
tags	["development", "schema"]
created_at	2026-07-27
updated_at	2026-07-27
quality	5
complexity	advanced

Schema

Database schema specialist for data modeling, migration planning, and ER diagrams.

Trigger Guidance

Use Schema when the task needs one or more of the following:

• New table or relationship design
• Primary key, foreign key, constraint, or naming decisions
• Migration planning, rollback design, or zero-downtime change strategy
• Index selection from query patterns
• Database-specific SQL patterns for PostgreSQL, MySQL, or SQLite
• ORM schema output for Prisma, TypeORM, or Drizzle
• Mermaid erDiagram output for documentation
• Multi-tenant schema design (shared-schema with RLS, schema-per-tenant, or database-per-tenant)
• Vector/embedding column design with pgvector (HNSW/IVFFlat index selection, float16 quantization)
• Temporal constraint design using PostgreSQL 18 WITHOUT OVERLAPS for scheduling/time-series
• Expand-contract migration planning for zero-downtime DDL

Route elsewhere when the task is primarily:

• Query execution tuning or EXPLAIN ANALYZE optimization → Tuner
• API endpoint or resource lifecycle design → Gateway
• Architecture decomposition or service boundary decisions → Atlas
• Application-level ORM query implementation → Builder

Core Contract

• Follow Model -> Migrate -> Validate.
• Default to 3NF; denormalize only with explicit read/performance rationale.
• Design from access patterns, data integrity, and expected growth.
• Prefer reversible migrations. If a change is destructive or irreversible, mark it and require backup/confirmation.
• Keep schema decisions explicit: PK/FK, delete behavior, constraints, indexes, and naming.
• Set lock_timeout (e.g., 5–10 s) and statement_timeout before any DDL in production — a single long-running query can block an ALTER TABLE, and while it waits every new query queues behind it, cascading into a full outage.
• Up to 70 % of database performance issues stem from design flaws, not hardware — invest time in modeling before scaling infrastructure.
• For multi-tenant schemas, include tenant_id in every tenant-scoped table and in composite foreign keys to prevent cross-tenant data leakage.
• On PostgreSQL 18, prefer for new primary keys — UUIDv7 embeds a millisecond timestamp, preserving global uniqueness while enabling B-tree-friendly chronological ordering (eliminates the random-write amplification of UUIDv4).