Mongodb 索引可选字段

Question

我的 mongodb 集合中有一些字段是搜索的可选部分。如果我不知道用户可能正在查询哪些字段，我如何才能一致地为该查询编制索引(即，无论参数如何，每个查询都将使用索引)？

Answer 1

您可以使用 Sparse Index

Sparse indexes only contain entries for documents that have the indexed field, even if the index field contains a null value. The index skips over any document that is missing the indexed field. The index is “sparse” because it does not include all documents of a collection. By contrast, non-sparse indexes contain all documents in a collection, storing null values for those documents that do not contain the indexed field.

db.addresses.createIndex( { "xmpp_id": 1 }, { sparse: true } )