如何在子集合中使用spring数据mongo @CompoundIndex?

问题描述

假设我拥有如下实体:

@Document(collection = "doc_a")
public class A {
  @Field("id")
  private Integer id;

  @Field("b")
  private Collection<B> b;
  ...
}


public class B {
  @Field("id")
  private Integer id;
  ...
}

是否可以将有关A.id和B.id的compoundIndex一起使用?

is it possible to use a compoundIndex with respect to A.id AND B.id together?

我的意思可能是:

@CompoundIndex(name = "aid_bid_idx", def = "{'id', 'b.id'}")

谢谢.

推荐答案

我在我的应用程序中尝试了这种复合索引，该索引也使用spring数据，并且工作正常.您只需要更正@CompoundIndex批注中的索引定义:

I've tried this kind of compound index in my app, that use spring data too, and worked properly.You only have to correct the index definition in @CompoundIndex annotation:

@CompoundIndex(name = "aid_bid_idx", def = "{'id' : 1, 'b.id' : 1}")
@Document(collection = "doc_a")
public class A {
  @Field("id")
  private Integer id;

  @Field("b")
  private Collection<B> b;
  ...
}

public class B {
  @Field("id")
  private Integer id;
  ...
}

如果在mongo shell中运行带有explain的查询(如下所示)，您将看到将使用索引* aid_bid_idx *.

If you run a query with explain (like the follows) in mongo shell, you'll see that the index *aid_bid_idx* will be used.

db.doc_a.find({ "id" : 1, "b.id" : 1}).explain()

结果将是这样的:

{
    "cursor" : "BtreeCursor aid_bid_idx",
    ...
}

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