# Introduction to SQL SQL is a data definition language that allows the specification of not only a set of relations but also information about each relation, including: * The schema for each relation * The domain of values associated with each attribute * Integrity constraints * The set of indices to be maintained for each relation * Security and authorization information for each relation * The physical storage structure of each relation on disk --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://vikram-bajaj.gitbook.io/cs-gy-6083-principles-of-database-systems/main-1/sql/introduction-to-sql.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.