SingleStoreDB allows developers to create external functions that can interact with external services, such as OpenAI's vector embedding API. These external functions can be used to get vector embeddings for text data directly from SQL queries, simplifying programming and reducing the need to round-trip data through an application. An example of how this works is shown in the article, where a Flask-based web application hosts an external function that calls OpenAI's vector embedding API to generate embeddings for given text strings. The generated embeddings can then be used to update a vector column in a SQL table in a single UPDATE statement. This approach allows developers to easily incorporate vector data into their applications and take advantage of the power of SQL.