neo4j 中节点和关系的物理存储模型
neo4j存储模型
The node records contain only a pointer to their first property and their first relationship (in what is oftentermed the _relationship chain). From here, we can follow the (doubly) linked-list of relationships until we find the one we’re interested in, the LIKES relationship from Node 1 to Node 2 in this case. Once we’ve found the relationship record of interest, we can simply read its properties if there are any via the same singly-linked list structure as node properties, or we can examine the node records that it relates via its start node and end node IDs. These IDs, multiplied by the node record size, of course give the immediate offset of both nodes in the node store file.
上面的英文摘自<Graph Databases>(作者：IanRobinson) 一书，描述了 neo4j 的存储模型。Node和Relationship 的 Property 是用一个 Key-Value 的双向列表来保存的； Node 的 Relatsionship 是用一个双向列表来保存的，通过关系，可以方便的找到关系的 from-to Node. Node 节点保存第1个属性和第1个关系ID。
通过上述存储模型，从一个Node-A开始，可以方便的遍历以该Node-A为起点的图。下面给个示例，来帮助理解上面的存储模型，存储文件的具体格式在第2章详细描述。
http://sunxiang0918.cn/2015/06/27/neo4j-%E5%BA%95%E5%B1%82%E5%AD%98%E5%82%A8%E7%BB%93%E6%9E%84%E5%88%86%E6%9E%90/