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GITBOOK-497: Updated the metadata page

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Ana Loznianu 2023-06-13 13:57:20 +00:00 committed by gitbook-bot
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@ -4,13 +4,13 @@ description: How can you enhance data discovery?
# Metadata
Imagine you're searching for data on Spanish almond production within a dApp operating within the Ocean ecosystem, managed by a European fruit and nut association. This hypothetical dApp may host a vast collection of datasets, making it essential to have a way to identify the relevant ones. One effective approach is to have **metadata** associated with each dataset to serve as valuable information about the data itself.
Imagine you're searching for data on Spanish almond production within a dApp operating within the Ocean ecosystem, managed by a European fruit and nut association. This hypothetical dApp may host a vast collection of datasets, making it essential to have a way to identify the relevant ones. What can we do about it? :thinking: One effective approach is to have **metadata** associated with each dataset to serve as valuable information about the data itself.
<figure><img src="../.gitbook/assets/data_everywhere.gif" alt=""><figcaption><p>Data discovery</p></figcaption></figure>
Metadata plays a **crucial role** in asset **discovery**, providing essential information such as **asset type, name, creation date, and licensing details**. Each data asset can have a [decentralized identifier (DID)](identifiers.md) that resolves to a DID document ([DDO](ddo-specification.md)) containing associated metadata. The DDO is essentially [JSON](https://www.json.org/) filling in metadata fields. To understand working with OCEAN DIDs, you can refer to the [DID documentation](identifiers.md). For a more comprehensive understanding of metadata structure, the [DDO Specification](ddo-specification.md) documentation provides in-depth information.
In general, any dApp within the Ocean ecosystem is required to store metadata for every listed dataset. It's important to note that dApps do not necessarily need to possess the datasets themselves; they primarily focus on storing and managing the associated metadata. While specific metadata requirements may vary, certain fundamental pieces of metadata, including:
In general, any dApp within the Ocean ecosystem is required to store metadata for every listed dataset. While specific metadata requirements may vary, certain fundamental pieces of metadata, including:
* **name**, e.g. “Largueta Almond Production: 1995 to 2005”
* **dateCreated**, e.g. “2007–01–20”
@ -30,7 +30,7 @@ Other metadata might also be available. For example:
DIDs and DDOs follow the [specification defined by the World Wide Web Consortium (W3C)](https://w3c-ccg.github.io/did-spec/).
**Decentralized identifiers** (DIDs) are a type of identifier that enable verifiable, decentralized digital identity. Each DID is associated with a unique entity, and DIDs may represent humans, objects, and more. A **DID Document** (DDO) is a JSON blob that holds information about the DID. Given a DID, a _resolver_ will return the DDO of that DID.
[**Decentralized identifiers**](identifiers.md) (DIDs) are a type of identifier that enable verifiable, decentralized digital identity. Each DID is associated with a unique entity, and DIDs may represent humans, objects, and more. A **DID Document** (DDO) is a JSON blob that holds information about the DID. Given a DID, a _resolver_ will return the DDO of that DID.
Decentralized identifiers (DIDs) are a type of identifier that enable verifiable, decentralized digital identity. Each DID is associated with a unique entity, and DIDs may represent humans, objects, and more.
@ -38,13 +38,13 @@ Decentralized identifiers (DIDs) are a type of identifier that enable verifiable
An _asset_ in Ocean represents a downloadable file, compute service, or similar. Each asset is a _resource_ under the control of a _publisher_. The Ocean network itself does _not_ store the actual resource (e.g. files).
An _asset_ has a DID and DDO. The DDO should include [metadata](did-ddo.md#metadata) about the asset, and define access in at least one [service](did-ddo.md#services). Only _owners_ or _delegated users_ can modify the DDO.
An _asset_ has a DID and DDO. The DDO should include metadata about the asset, and define access in at least one [service](did-ddo.md#services). Only _owners_ or _delegated users_ can modify the DDO.
All DDOs are stored on-chain in encrypted form to be fully GDPR-compatible. A metadata cache like [_Aquarius_](aquarius/) can help in reading, decrypting, and searching through encrypted DDO data from the chain. Because the file URLs are encrypted on top of the full DDO encryption, returning unencrypted DDOs e.g. via an API is safe to do as the file URLs will still stay encrypted.
#### Publishing & Retrieving DDOs
The DDO is stored on-chain as part of the NFT contract and stored in encrypted form using the private key of the [_Provider_](provider/). To resolve it, a metadata cache like [_Aquarius_](aquarius/) must query the provider to decrypt the DDO.
The DDO is stored on-chain as part of the NFT contract and stored in encrypted form using the private key of the [_Provider_](provider/). To resolve it, a metadata cache like [_Aquarius_](aquarius/) must query the [Provider](provider/) to decrypt the DDO.
Here is the flow:
@ -77,4 +77,8 @@ function setMetadata(uint8 _metaDataState, string calldata _metaDataDecryptorUrl
While we utilize a specific DDO structure, you have the flexibility to customize it according to your unique requirements. However, to enable seamless processing, it is essential to have your own Aquarius instance that can handle your modified DDO.
{% endhint %}
{% hint style="info" %}
As developers, we understand that you eat, breathe, and live code. That's why we invite you to explore our [ocean.py](ocean.py/publish-flow.md#publishing-alternatives) and [ocean.js](ocean.js/update-metadata.md) pages, where you'll find practical examples of how to set up and update metadata for an asset :computer:
{% endhint %}
You'll have more information about the DIDs, on the [Identifiers](identifiers.md) page.