mongodb index _id
Wildcard indexes omit the _id field by default. To include the _id field in the wildcard index, you must explicitly include it in the wildcardProjection document:. ,2020年4月8日 — My instinct was no, so I just tried it: > db.foo.find() > db.foo.getIndexes() [ "v" : 1, "key" : "_id" : 1 }, "name" : "_id_", "ns" : "foo.foo" } ...
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 mongodb index _id 相關參考資料
Add _id when ensuring index? - Stack Overflow
2012年7月3日 — You don't need to implicitly create index on the _id field, it's done automatically. See the mongo documentation: The _id Index. https://stackoverflow.com db.collection.createIndex() — MongoDB Manual
Wildcard indexes omit the _id field by default. To include the _id field in the wildcard index, you must explicitly include it in the wildcardProjection document:. https://docs.mongodb.com Does mongodb automatically create an index on the _id field ...
2020年4月8日 — My instinct was no, so I just tried it: > db.foo.find() > db.foo.getIndexes() [ "v" : 1, "key" : "_id" : 1 }, "name" : "_id_", &q... https://stackoverflow.com Indexes — MongoDB Manual
https://docs.mongodb.com Manage Indexes — MongoDB Manual
For example, the following operation removes an ascending index on the tax-id field in the accounts collection: copy. copied. db.accounts.dropIndex( "tax-id": 1 } ... https://docs.mongodb.com Multikey Indexes — MongoDB Manual
_id: 1, a: [ 1, 2 ], b: [ 1, 2 ], category: "AB - both arrays" }. You cannot create a compound multikey index a: 1, b: 1 } on the collection since both the a and b fields ... https://docs.mongodb.com Single Field Indexes — MongoDB Manual
MongoDB provides complete support for indexes on any field in a collection of documents. By default, all collections have an index on the _id field, and ... https://docs.mongodb.com Unique Indexes — MongoDB Manual
... i.e. enforces uniqueness for the indexed fields. By default, MongoDB creates a unique index on the _id field during the creation of a collection. New Internal ... https://docs.mongodb.com When is the _id index used? - Database Administrators Stack ...
2015年9月21日 — In MongoDB, documents stored in a collection require a unique _id field that acts as a primary key. MongoDB uses ObjectIds as the default value ... https://dba.stackexchange.com [mongoDB]index功能的筆記@ 雷伊的工作心得:: 隨意窩Xuite日誌
在預設的情況下，_id欄位一開始就己經是index，同時_id也是primary key，如果一筆資料沒有指定_id的值，那麼系統會配給他一個12-byte的值（資料型態為ObjectID ... https://blog.xuite.net |