What is a characteristic of a non-relational database?

Non-relational databases are characterized by their flexible schema, often referred to as "schema-on-read." Data is frequently stored in formats like JSON, where each entity or document is self-contained and includes its own structure (i.e., the field names and the data). This makes the entities "self-describing," as the structure is embedded with the data itself rather than being enforced by a separate, predefined table schema. This flexibility allows for storing data with varying structures within the same collection.

A. A fixed schema (schema-on-write) is a defining characteristic of relational databases, where the table structure must be defined before data can be inserted.

C. Full support for Transact-SQL is specific to Microsoft's relational database systems, like SQL Server and Azure SQL Database, not a general characteristic of non-relational databases.

1. Microsoft Learn, DP-900T00: Microsoft Azure Data Fundamentals, Module 2: Describe concepts of non-relational data, Unit 2: Describe non-relational data. This document states, "In a document database, each document is a self-contained unit of data. The fields in the document are self-describing." It contrasts this with relational databases that use a "schema-on-write" approach.

2. Microsoft Learn, DP-900T00: Microsoft Azure Data Fundamentals, Module 2: Describe concepts of non-relational data, Unit 1: Introduction. This unit introduces the concept of schema flexibility, stating, "Non-relational databases are often a better fit for data that doesn't have a rigid schema." This supports the idea that a fixed schema (Option A) is incorrect.

3. Microsoft Learn, DP-900T00: Microsoft Azure Data Fundamentals, Module 1: Describe core data concepts, Unit 4: Describe relational data. This source clarifies that relational databases use Structured Query Language (SQL), and Transact-SQL is a specific dialect for Microsoft products, confirming that T-SQL (Option C) is a feature of relational, not non-relational, systems.