design-azure-sql-schema

Designs tables for Azure SQL Database so the first index or long value does not force a rebuild. Covers index key limits in bytes, why Unicode sizing makes NVARCHAR(850) and NVARCHAR(450) the real ceilings, collation decided once at CREATE DATABASE, the implicit conversion that turns a lookup into a scan, identity gaps of a thousand after a restart, unique columns that accept exactly one NULL. Use when creating or reviewing tables, porting a PostgreSQL or MySQL schema to Azure SQL Database, choosing a key, a string length or a collation, or reports a warning about maximum key length, an insert failing long after its migration, a lookup that suddenly scans, identity values that jumped, or a duplicate key on NULL. The engine rule under the mappers: ef-core-azure-sql and sqlalchemy-azure-sql own how each expresses it, t-sql-correctness syntax, vector-search-azure-sql vector columns.