Definition
User-Defined Functions, or UDFs, are custom code snippets that extend the capabilities of a database or programming environment. They allow developers to encapsulate complex logic into reusable units, simplifying queries and data processing. UDFs are invoked like built-in functions, taking specific inputs and returning a calculated output. This capability is crucial for automating repetitive tasks, performing specialized calculations, and improving the efficiency of data analysis. For instance, a UDF could be created to standardize address formats across a customer database. Unlike stored procedures which can perform multiple operations and modify data, UDFs are primarily designed for computation and returning a single value. This concept is relevant in database administration and data engineering domains, often appearing in discussions related to data warehousing and big data platforms.