What is a schema?

• A. A formal definition of a dataset's structure.
• B. A list of attributes and their values.
• C. A workflow for manipulating data types.
• D. A tool for scanning for missing data.

Answer: (A)

A schema is a formal definition of a dataset's structure. It specifies what entities or tables exist, what attributes they have, the data types of those attributes, and any constraints or relationships between them. The actual data values live in the dataset, while the schema defines the skeleton and rules that describe how that data is organized. For example, a customer dataset might define fields like CustomerID (integer), Name (text), and Email (text), with CustomerID required to be unique. This distinction makes the schema the best choice because it focuses on the layout and constraints that govern the data, not on the record values themselves, a list of attributes and values, a transformation workflow, or a data-quality scan.