Finding unambiguous diagrammatic representations for first-order logical formulas and relational queries with arbitrarily nested disjunctions has been a surprisingly long-standing unsolved problem. We refer to this problem as the disjunction problem (of diagrammatic query representations). This work solves the disjunction problem. Our solution unifies, generalizes, and overcomes the shortcomings of prior approaches for disjunctions. It extends the recently proposed Relational Diagrams and is identical for disjunction-free queries. However, it can preserve the relational patterns and the safety for all well-formed Tuple Relational Calculus (TRC) queries, even with arbitrary disjunctions. Additionally, its size is proportional to the original TRC query and can thus be exponentially more succinct than Relational Diagrams.

翻译：为包含任意嵌套析取的一阶逻辑公式和关系查询寻找无歧义的图解表示，长期以来一直是一个令人惊讶的悬而未决的问题。我们将此问题称为（图解查询表示的）析取问题。本研究解决了该析取问题。我们的解决方案统一、概括并克服了先前处理析取方法的缺点。它扩展了最近提出的关系图，并且对于无析取查询是相同的。然而，即使存在任意析取，它也能为所有良构的元组关系演算查询保持关系模式和安全特性。此外，其大小与原始TRC查询成正比，因此可以比关系图指数级地更简洁。