Database schema design

Navrhni database schema pro [APPLICATION TYPE]. Requirements:\n\n**Entities:**\n[SEZNAM ENTIT - např. Users, Products, Orders]\n\n**Relationships:**\n[VZTAHY - např. User has many Orders, Order belongs to User]\n\n**Business Rules:**\n[PRAVIDLA - např. Order cannot be deleted, User email must be unique]\n\n**Design Requirements:**\n1. Normalization: [1NF/2NF/3NF/BCNF]\n2. Indexing strategy\n3. Foreign key constraints\n4. Check constraints\n5. Default values\n6. Timestamps (created_at, updated_at)\n\n**Performance:**\n- Expected scale: [POČET RECORDS]\n- Critical queries: [QUERIES]\n\n**Output:**\n- SQL schema (CREATE TABLE statements)\n- ER diagram description\n- Index recommendations\n- Migration script\n\nDatabase: [POSTGRESQL/MYSQL/MONGODB].