Expert database design skill for architecting, modeling, and optimizing relational and non-relational databases. ALWAYS use this skill when the user mentions: designing a database, creating a schema, writing migrations, data modeling, ERD diagrams, normalization, choosing between SQL and NoSQL, database performance, indexing strategy, designing tables, entity relationships, foreign keys, constraints, multi-tenancy, audit logging, soft delete, or any task that involves structuring data at the database level. Also use when the user says things like "tôi cần thiết kế DB", "giúp tôi làm schema", "database cho hệ thống X", "nên dùng SQL hay NoSQL", or any Vietnamese/English phrasing about organizing data storage. Even if the user only describes a system or feature (e.g., "tôi muốn làm app đặt đồ ăn"), proactively apply this skill to propose a complete database design.