This section describes the aggregation workflow used to gather the bibliographic material from Datacite and the relative mapping.
## Datacite datasource
[Datacite](https://datacite.org/index.html) is a leading global non-profit organisation that provides persistent identifiers (DOIs) for research data and other research outputs.
## Datacite API
The [DataCite REST API](https://support.datacite.org/docs/api) allows users to retrieve, query, and browse Datacite metadata records. In particular, it exposes a method for harvesting new records incrementally.
```
https://api.datacite.org/dois?page[cursor]=$CURSOR&page[size]=$NUMBER_OF_ITEM_PER_PAGE&query=updated:[$FROM_DATE_TIMESAMP TO $TO_DATE_TIMESAMP]
```
On this API Request, we introduce some variables:
- **CURSOR**: The value of the cursor to iterate the pages; the cursor is extracted from each API response and used in the next request.
- **NUMBER_OF_ITEM_PER_PAGE**: (max 1000) defines how many records must be returned within each API response.
- **FROM_DATE_TIMESAMP, TO_DATE_TIMESAMP** interval timestamp of the updated record.
Each record contains two pieces of information needed for incremental harvesting:
- **isActive**: tells if the record is deleted (`isActive:false`)
- **updated**: timestamp of last update
## Collection Workflow
The collection workflow is responsible for aggregating new records. Each record is stored locally on a table with the following schema:
- **DOI**: The DOI of the Datacite record (it is the primary key)
- **update_timestamp**: the last update date timestamp
- **json**: the native record JSON
The metadata collection process identifies the most recent record date available locally and uses such date to requests the records to the Datacite API, populating the **FROM_DATE_TIMESAMP** variable. The records in the API response are included in the local storage in upsert mode.
| `id` | `\attributes\doi` | id in the form `doi_________::md5(doi)` |
| <ul><li>`instance`</li><li>`instance.type`</li></ul> | <ul><li>`\attributes\types\resourceType`</li><li>`\attributes\types\resourceTypeGeneral`</li><li>`attributes\types\schemaOrg`</li></ul> | Use the vocabulary **_dnet:publication_resource_** to find a synonym to one of these terms and get the `instance.type`. |
| `type` | <ul><li>`\attributes\types\resourceType`</li><li>`\attributes\types\resourceTypeGeneral`</li><li>`attributes\types\schemaOrg`</li></ul> | Using the **_dnet:result_typologies_** vocabulary, we look up the `instance.type` synonym to generate one of the following main entities: <ul><li>`publication`</li><li>`dataset`</li><li>`software`</li><li>`otherresearchproduct`</li></ul> |
| `pid` | `\attributes\doi` | `scheme = doi` |
| `originalid` | `\attributes\doi` | |
| `dateofcollection` | `attributes\updated` | the timestamp is defined in milliseconds we convert to "yyyy-MM-dd'T'HH:mm:ssZ" format |
| `author` | `\attributes\creators` | Each creator field will be mapped in the author entity below the subfield. **If the record has no Creator it will be skipped** |
| `author.fullname` | `\attributes\creators\name` | if name is not defined, we construct from given and family name |
| `author.rank` | | Incremental index starting from 1 |
| `author.pid` | `\attributes\creators\nameIdentifiers` | this is a list of pids associated to the creator |
| `author.pid.scheme` | `\attributes\creators\nameIdentifiers` | mapping with vocabulary **dnet:pid_types** |
| `author.pid.value` | `\attributes\creators\nameIdentifiers/nameIdentifier` | the pid value |
| `maintitle` | `\attributes\titles` | Titles whose title type is null or title type is Main |
| `subtitle` | `\attributes\titles` | Titles whose title type is Subtitle since the title type vocabulary in OpenAIRE use the datacite title type vocabulary |
| **date section** | | for each date in particular for DOI starting with _10.14457_ we Apply a fix thai date convert a date to ThaiBuddhistDate and reformat to local one see ticket [#6791](https://support.openaire.eu/issues/6791) |
| `publicationdate` | `\attributes\dates` | where `dateType` is **issued** |
| `publicationdate` | `\attributes\publicationYear` | we create this date format `01-01-publicationYear` |
| `embargoenddate` | `\attributes\dates` | where `dateType` is **available** |
| `isProducedBy/produces` | `attributes\fundingReferences` | `result/project` | only when the fundingReferences matches the pattern `(info:eu-repo/grantagreement/ec/h2020/)(\d{6})(.*)` |
| `IsProvidedBy/provides` | | `result/datasource` | Datasource is always set to `Datacite` |
| `isHostedBy/host` | `\attributes\relationships\client\id` | `result/datasource` | we defined a curated map clientId/Datasource if we found a match we create an _hostedBy Relation_ |
| `isRelatedTo` | `\attribute\relatedIdentifiers` | `result/result` | we create relationships whenever the pid of the target is resolved on the Research Graph |
