构建含相对属性/关系的对象数据库：Neo4j与MongoDB选型咨询

Great question! Let's break down which database fits your needs better based on your specific use case of storing objects with interdependent attributes and complex relationships.

• Native graph structure for object relationships: Your core need revolves around interdependent objects (like A's height relying on B, and B's height relying on A). Neo4j treats objects as nodes and their connections as edges—this native graph model makes querying and managing these reciprocal dependencies far more intuitive and performant than document-based alternatives.
• Straightforward handling of attribute expressions: For logic like "A's weight = B's weight + 2", Neo4j's Cypher query language lets you directly traverse related nodes and compute values in a single query. Here's a quick example:

  MATCH (a:Object {name: 'A'}), (b:Object {name: 'B'})
  SET a.weight = b.weight + 2
  RETURN a, b
  

  This approach keeps your dependency logic clean and easy to maintain, without needing extra application-layer code.
• Flexible relationship scaling: If you later need to add new relationship types (like "parent-child", "associated with", or "derived from"), Neo4j lets you define these on the fly without altering your node structure—perfect for evolving your data model over time.

• Better for non-relationship-heavy data: MongoDB shines when your focus is on storing individual objects with flexible attributes, and relationships are secondary. But for your use case of interconnected, mutually dependent objects, MongoDB would force you to simulate relationships via document references or nested fields. This leads to:
  • Slower, more complex queries (you'd have to fetch related objects separately and compute dependencies in your application code)
  • Headaches with circular dependencies (like A relying on B and vice versa), which require messy workarounds in aggregation pipelines or app logic.

If your priority is managing complex object relationships and handling attribute expressions that depend on other objects, Neo4j is the clear choice. Its graph-native design and Cypher language are built exactly for this kind of interconnected data.

MongoDB would only make sense if your needs shift to prioritizing standalone object storage with minimal relationships. But based on your example, Neo4j aligns perfectly with what you're trying to build.

内容的提问来源于stack exchange，提问作者Bach