Creating Key-value example readme

KeyValueExamples.md

@@ -0,0 +1,57 @@
+<!--
+Copyright 2022 Ocean Protocol Foundation
+SPDX-License-Identifier: Apache-2.0
+-->
+
+# Quickstart: Key-value database
+
+Data NFTs can store arbitrary key-value pairs on-chain. This opens up their usage for a broad variety of applications, such as comments & ratings, attestations, and privately sharing data (when the value is encrypted).
+
+Let's see how!
+
+Here are the steps:
+
+1. Setup
+2. Publish data NFT
+3. Add key-value pair to data NFT
+4. Retrieve value from data NFT
+
+## 1. Setup
+
+Ensure that you've already (a) [installed Ocean](install.md), and (b) [set up locally](setup-local.md) or [remotely](setup-remote.md).
+
+## 2. Publish data NFT
+
+```javascript
+// from ocean_lib.models.arguments import DataNFTArguments
+// data_nft = ocean.data_nft_factory.create(DataNFTArguments('NFT1', 'NFT1'), alice)
+```
+
+## 3. Add key-value pair to data NFT
+
+```javascript
+// # Key-value pair
+// key = "fav_color"
+// value = b"blue"
+
+// # prep key for setter
+// from web3.main import Web3
+// key_hash = Web3.keccak(text=key)  # Contract/ERC725 requires keccak256 hash
+
+// # set
+// data_nft.setNewData(key_hash, value, {"from": alice})
+```
+
+## 4. Retrieve value from data NFT
+
+```javascript
+// value2_hex = data_nft.getData(key_hash)
+// value2 = value2_hex.decode('ascii')
+// print(f"Found that {key} = {value2}")
+```
+
+That's it! Note the simplicity. All data was stored and retrieved from on-chain. We don't need Ocean Provider or Ocean Aquarius for these use cases (though the latter can help for fast querying & retrieval).
+
+We can also encrypt the data. Other quickstarts explore this.
+
+Under the hood, it uses [ERC725](https://erc725alliance.org/), which augments ERC721 with a well-defined way to set and get key-value pairs.