This study examines the extent to which structural constraints specified in conceptual schemas are represented after transformation to logical schemas. Focusing on the conceptual-to-logical mapping, an Entity-Relationship (ER) model containing binary relationship types is transformed into a Relational Database Schema (RDS). The analysis is conducted under the classical transformation framework in which the logical schema is defined solely by primary key (PK) and foreign key (FK) constraints. Using generalised ER models with variable structural constraint values, the resulting RDS structures are evaluated to determine whether minimum and maximum participation constraints are represented unambiguously. The findings show that, for one-to-one and one-to-many relationships, RDSs do not unambiguously capture minimum participation constraints and do not encode exact maximum participation beyond limited cases. For many-to-many relationships, the schema indicates only that maximum cardinalities exceed one, without preserving exact values. These results clarify the representational limits of standard ER-to-relational transformations and have implications for schema design and constraint enforcement.

翻译：本研究探讨概念模式中定义的结构约束在转换为逻辑模式后的表示程度。聚焦于概念至逻辑的映射过程，将包含二元关系类型的实体关系模型转换为关系数据库模式。分析在经典转换框架下进行，其中逻辑模式仅通过主键和外键约束定义。通过使用具有可变结构约束值的广义实体关系模型，评估生成的关系数据库模式结构，以确定最小与最大参与约束是否得到明确表示。研究结果表明：对于一对一和一对多关系，关系数据库模式无法明确表示最小参与约束，且除有限情况外无法编码精确的最大参与约束；对于多对多关系，模式仅能表明最大基数大于一，而无法保持精确数值。这些结果阐明了标准实体关系至关系型转换的表示局限性，对模式设计与约束实施具有重要启示。