This change extends the HTTP REST API for bulk imports as follows:
When documents are imported and the `_key` attribute is specified for them, the import can be
used for inserting and updating/replacing documents. Previously, the import could be used for
inserting new documents only, and re-inserting a document with an existing would have failed
with a *unique key constraint violated* error.
The above behavior is still the default. However, the API now allows controlling the behavior
in case of a unique key constraint error via the optional URL parameter `onDuplicate`.
This parameter can have one of the following values:
- `error`: when a unique key constraint error occurs, do not import or update the document but
report an error. This is the default.
- `update`: when a unique key constraint error occurs, try to (partially) update the existing
document with the data specified in the import. This may still fail if the document would
violate secondary unique indexes. Only the attributes present in the import data will be
updated and other attributes already present will be preserved. The number of updated documents
will be reported in the `updated` attribute of the HTTP API result.
- `replace`: when a unique key constraint error occurs, try to fully replace the existing
document with the data specified in the import. This may still fail if the document would
violate secondary unique indexes. The number of replaced documents will be reported in the
`updated` attribute of the HTTP API result.
- `ignore`: when a unique key constraint error occurs, ignore this error. There will be no
insert, update or replace for the particular document. Ignored documents will be reported
separately in the `ignored` attribute of the HTTP API result.
The result of the HTTP import API will now contain the attributes `ignored` and `updated`, which
contain the number of ignored and updated documents respectively. These attributes will contain a
value of zero unless the `onDuplicate` URL parameter is set to either `update` or `replace`
(in this case the `updated` attribute may contain non-zero values) or `ignore` (in this case the
`ignored` attribute may contain a non-zero value).
jsteemann
Max Neunhoeffer