如何最好地查询 Datomic 的 n 度子图？

Question

Datomic 文档展示了如何递归地选择一些属性： [:person/firstName :person/lastName {:person/friends 6}]

但我想拉取所有属性（我在查询时不知道它们）。

[* {:person/friends 6}] 不重复...是否有排除我想要重复的关系的通配符？有没有办法对拉取进行递归规范并使用通配符？

或者有没有更好的方法来构建这个查询？

Answer 1

蒂莫西，

您应该能够使用 ["*" {:person/friends 6}] 来实现您正在寻找的行为。

使用 Day of Datomic pull_recursion.clj 中的示例：

(d/pull (d/db conn) '[:person/name {:person/friend 2}] anne-id)
;; {:person/name "anne", :person/friend [{:person/name "bob", :person/friend [{:person/name "anne"} {:person/name "lucille"}]} {:person/name "james", :person/friend [{:person/name "anne"} {:person/name "lucille"}]}]}

(d/pull (d/db conn) '["*" {:person/friend 2}] anne-id)
;; {":db/id" 17592186045418, ":person/name" "anne", ":person/friend" [{":db/id" 17592186045419} {":db/id" 17592186045420}], :person/friend [{":db/id" 17592186045419, ":person/name" "bob", ":person/friend" [{":db/id" 17592186045418} {":db/id" 17592186045421}], :person/friend [{":db/id" 17592186045418, ":person/name" "anne", ":person/friend" [{":db/id" 17592186045419} {":db/id" 17592186045420}], :person/friend [{":db/id" 17592186045419} {":db/id" 17592186045420}]} {":db/id" 17592186045421, ":person/name" "lucille", ":person/friend" [{":db/id" 17592186045419}], :person/friend [{":db/id" 17592186045419}]}]} {":db/id" 17592186045420, ":person/name" "james", ":person/friend" [{":db/id" 17592186045418} {":db/id" 17592186045421}], :person/friend [{":db/id" 17592186045418, ":person/name" "anne", ":person/friend" [{":db/id" 17592186045419} {":db/id" 17592186045420}], :person/friend [{":db/id" 17592186045419} {":db/id" 17592186045420}]} {":db/id" 17592186045421, ":person/name" "lucille", ":person/friend" [{":db/id" 17592186045419}], :person/friend [{":db/id" 17592186045419}]}]}]}

马歇尔

如何最好地查询 Datomic 的 n 度子图？

How best can I query Datomic for a n-degrees subgraph?

datomic