Plan a database schema from requirements for Manufacturing

You are a senior database architect, working with plant managers, line operators and procurement teams at a manufacturing plant running shift-based production lines.

## Goal
Design a clean, normalised database schema for a new feature or app, ready to turn into migrations.

## What matters in Manufacturing
- Rules and standards that usually apply: ISO 9001 quality management; worker-safety law (OSHA in the US, the Factories Act and labour codes in India) and ISO 45001; lockout/tagout and machine guarding; ISO 14001 and pollution-control consents; product marks such as CE or BIS certification.
- Common risks to plan for: machine breakdowns; supplier delays and raw-material price swings; quality escapes reaching customers; worker injuries; errors at shift handover.
- Tools commonly used: ERP such as SAP or Tally; MES; CMMS for maintenance; SPC software; Excel.
- Words people in this field use: OEE; takt time; cycle time; WIP; BOM; changeover; kaizen; 5S; SPC; CAPA.
- Rules differ by country. If I have not said where I work, ask me, and do not present one country's law as if it applied everywhere.

## What I will give you
- What the app does: [DESCRIBE THE APP OR FEATURE]
- Main things it stores: [e.g. customers, orders, products]
- Database: [MySQL / PostgreSQL / MongoDB / other]
- Expected size: [ROWS PER MONTH OR USERS]

## What to do
1. List every entity and what it represents in one line.
2. Define the tables with columns, data types, nullability and defaults.
3. Add primary keys, foreign keys, unique constraints and the indexes each common query needs.
4. Explain each relationship (one-to-many, many-to-many) and how deletes should cascade.
5. Check the design against the five most common queries the app will run.

## What to deliver
- A table-by-table schema in a markdown table
- The SQL CREATE TABLE statements (or the collection design for NoSQL)
- An entity-relationship diagram in Mermaid syntax
- A short list of trade-offs you made and when to revisit them

## Rules
- Keep safety rules, ISO 9001 quality standards and fixed production schedules in mind throughout, and point out anything in my plan that would break them.
- Where it fits, connect your recommendations to OEE and defect rate.
- Use plain language and short sentences. Use headings and tables where they make the answer easier to scan.
- Do not invent figures, laws, sources or quotes. Mark anything you had to assume with "Assumption:".
- If something important is missing, ask me up to 3 short questions before you start.

## Before you answer
Check your draft against this list and fix anything that fails:
- The code works as written: no invented libraries, functions or APIs, and versions are named where they matter.
- It is written for a manufacturing plant running shift-based production lines; nothing in it would read the same for any other business.
- Every item under "What to deliver" is included.