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Query Modifiers¶
In addition to the MongoDB Query Operators, there are a number of “meta” operators that let you modify the output or behavior of a query.
注解
- Deprecated in the mongo Shell since v3.2
- Starting in v3.2, the query “meta” operators are deprecated in the mongo shell. In the mongo shell, use the cursor methods instead.
The driver interfaces may provide cursor methods that wrap these options. When possible, use these methods; otherwise, you can add these options using either of the following syntax:
db.collection.find( { <query> } )._addSpecial( <option> )
db.collection.find( { $query: { <query> }, <option> } )
Operators¶
Modifiers¶
注解
- Deprecated in the mongo Shell since v3.2
- Starting in v3.2, the query “meta” operators are deprecated in the mongo shell. In the mongo shell, use the cursor methods instead.
| Name | Description |
|---|---|
| $comment | Adds a comment to the query to identify queries in the database profiler output. |
| $explain | Forces MongoDB to report on query execution plans. See explain(). |
| $hint | Forces MongoDB to use a specific index. See hint() |
| $maxScan | Limits the number of documents scanned. |
| $maxTimeMS | Specifies a cumulative time limit in milliseconds for processing operations on a cursor. See maxTimeMS(). |
| $max | Specifies an exclusive upper limit for the index to use in a query. See max(). |
| $min | Specifies an inclusive lower limit for the index to use in a query. See min(). |
| $orderby | Returns a cursor with documents sorted according to a sort specification. See sort(). |
| $returnKey | Forces the cursor to only return fields included in the index. |
| $showDiskLoc | Modifies the documents returned to include references to the on-disk location of each document. |
| $snapshot | Guarantees that a query returns each document no more than once. See snapshot(). |
| $query | Wraps a query document. |