In database design, Composite Keys are used to uniquely identify records and prevent data duplication. However, they require more memory and storage space than single keys, and can make queries more CPU-intensive. Surrogate Keys are an alternative that can overcome some of these limitations, but they can also introduce new disadvantages. To address these challenges, a new type of key called a Reversible Numeric Composite Key (RNCK) has been developed. RNCK is a single number that encodes multiple data attributes, and can be decoded back to the original values. This makes it possible to achieve the benefits of both Composite Keys and Surrogate Keys, while overcoming some of their limitations. RNCK has been shown to improve query performance and reduce memory and storage requirements. It can be used in relational databases, large static datasets, and key-value caching systems. RNCK has been successfully used in production systems for several years.

翻译：在数据库设计中，复合键用于唯一标识记录并防止数据重复。然而，相较于单键，复合键需要更多的内存和存储空间，且可能增加查询的CPU开销。代理键作为一种替代方案，虽能克服部分上述限制，但也会引入新的弊端。为应对这些挑战，一种名为可逆数值复合键（RNCK）的新型键被研发出来。RNCK是单一数值，可编码多个数据属性，并能够解码还原为原始值。这使其在兼得复合键与代理键优势的同时，克服了二者的部分局限性。实践证明，RNCK能提升查询性能，并减少内存与存储需求。该键可应用于关系型数据库、大规模静态数据集以及键值缓存系统。目前，RNCK已在生产系统中成功应用多年。