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Type:
Improvement
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Resolution: Won't Do
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Priority:
Major - P3
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None
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Affects Version/s: None
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Component/s: None
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None
. h4. Description of Drivers Ticket:
This stage will eventually replace the new modes of $out, but for now will be separate.
The syntax will be:
{$merge: {
into: "collection name" OR {db: "db name", coll: "collection name"},
on: <fields used to uniquely identify a document>,
let: <optional, variables to be in scope for pipeline below>,
whenMatched: "replace|keepExisting|fail|merge|pipeline",
whenNotMatched: "insert|discard|fail"
}}
For this ticket, we will only support the combination of modes already supported by $out:
mode "insertDocuments":
{$merge: {
into: "x",
on: "x_id"
whenMatched: "fail",
whenNotMatched: "insert"
}}
mode "replaceDocuments":
{$merge: {
into: "x",
on: "x_id"
whenMatched: "replaceWithNew",
whenNotMatched: "insert"
}}
In future tickets we'll add support for other modes.
See DRIVERS-873 for updated details.
- is depended on by
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DRIVERS-671 Finer-grained updates from aggregation via $merge
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- Closed
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