> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/mariadb-quickstart-guides/database-applications/introduction-and-background.md). # Introduction & Background ## Introduction When designing database-based applications, one aspect that might always be considered at first is how you are supposed to maintain these applications; here, we mean maintenance in the sense of application code and database schemas being upgraded and how this can be done with minimum downtime and effort. This document aims to look at some important aspects of this, from database schema design to application code. Most of these are not strict rules, but rather aspects to consider when working with applications. The document does not cover general application code aspects, only the aspects that deal with the database part of applications. ## Background to Relational Database Applications Relational database systems, more or less all of them using the SQL query language, have been around since the early 1980s, and things have changed a lot over that time. One aspect that applications using relational databases introduced was the separation of the application, dealing with logic, presentation, user interaction and similar aspects on one hand and the database structure and design on the other. With relational databases came the relational database modelling and eventually the different normal forms of database design. Much of this has relaxed these days, but there are still things to consider here. The introduction of logic in the database layer, such as stored procedures, triggers and other aspects, is somewhat blurring the line between code and data, but the general rules still hold. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## 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, and the optional `goal` query parameter: ``` GET https://mariadb.com/docs/server/mariadb-quickstart-guides/database-applications/introduction-and-background.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.