Self-tuning is a feature of autonomic databases that includes the problem of automatic schema design. It aims at providing an optimized schema that increases the overall database performance. While in relational databases automatic schema design focuses on the automated design of the physical schema, in NoSQL databases all levels of representation are considered: conceptual, logical, and physical. This is mainly because the latter are mostly schema-less and lack a standard schema design procedure as is the case for SQL databases. In this work, we carry out a systematic literature survey on automatic schema design in both SQL and NoSQL databases. We identify the levels of representation and the methods that are used for the schema design problem, and we present a novel taxonomy to classify and compare different schema design solutions. Our comprehensive analysis demonstrates that, despite substantial progress that has been made, schema design is still a developing field and considerable challenges need to be addressed, notably for NoSQL databases. We highlight the most important findings from the results of our analysis and identify areas for future research work.

自调整是自主数据库的一项功能，其中包括自动模式设计问题。它的目的是提供一个优化的模式来提高数据库的整体性能。在关系数据库中，自动模式设计侧重于物理模式的自动化设计，而在 NoSQL 数据库中，会考虑所有级别的表示：概念、逻辑和物理。这主要是因为后者大多是无模式的，并且缺乏 SQL 数据库的标准模式设计过程。在这项工作中，我们对 SQL 和 NoSQL 数据库中的自动模式设计进行了系统的文献调查。我们确定了用于模式设计问题的表示级别和方法，并提出了一种新颖的分类法来对不同的模式设计解决方案进行分类和比较。我们的综合分析表明，尽管已经取得了实质性进展，模式设计仍然是一个发展中的领域，需要解决相当大的挑战，特别是对于 NoSQL 数据库。我们强调分析结果中最重要的发现，并确定未来研究工作的领域。