Explain JSON Column mapping in EF Core 7+.

EF Core 7+ natively supports mapping complex C# objects to JSON columns in the database, allowing NoSQL-like querying in relational DBs.

You map a property to JSON using OwnsOne(...).ToJson(). EF Core automatically serializes the object to JSON on save and deserializes it on retrieval. Crucially, it translates LINQ queries against the object's properties into native database JSON querying functions (like JSON_VALUE in SQL Server).