# To build a social graph

> This protocol supports all graph databases conforming to the RDF specification.

We can have a simple social graph by importing the RDF data constructed from the last chapter.

<figure><img src="https://2101283974-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYeYon1a8IZta2Zm96hF1%2Fuploads%2Fgit-blob-d5ef5305e862945ffd0460281012c6a1c504be94%2Ffollow%20(2).png?alt=media" alt=""><figcaption><p>Figure 7-3 A simple social graph</p></figcaption></figure>

## To use Neptune

> [Amazon Neptune](https://docs.aws.amazon.com/zh_cn/neptune/latest/userguide/intro.html) is a fast and scalable graph database service. It can efficiently store and navigate highly interconnected data. Its query processing engine is optimized for leading graph query languages such as Apache TinkerPop™ Gremlin and W3C's RDF SPARQL. Neptune provides high performance via these open graph frameworks and standard APIs.

With [Amazon Neptune](https://docs.aws.amazon.com/zh_cn/neptune/latest/userguide/intro.html) we can build a social graph using users' behavioral data on the blockchain.

Steps:

1. Launch a Neptune instance via the [aws console](https://ap-northeast-1.console.aws.amazon.com/neptune/home).
2. Composite the sparql constructed from the last chapter into an "insert" command in Neptune:

```sparql
update=PREFIX : <http://relationlabs.ai/entity/>
PREFIX p: <http://relationlabs.ai/property/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
INSERT DATA {GRAPH <http://relationlabs.ai/relationship> {
:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe a :Soul;
    p:name "Alice" .
:Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e a :Soul;
    p:name "Bob" .
:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe p:following :Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e .
}}
```

3. Call the Neptune service interface to save RDF:

```shell
curl -X POST --data-binary 'update=PREFIX : <http://relationlabs.ai/entity/>
PREFIX p: <http://relationlabs.ai/property/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
INSERT DATA {GRAPH <http://relationlabs.ai/relationship> {
:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe a :Soul;
    p:name "Alice" .
:Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e a :Soul;
    p:name "Bob" .
:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe p:following :Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e .  }}' https://your-neptune-endpoint:port/sparql
```

By now we have indexed the data `Alice follow Bob` into the graph database. We can query the data via the Neptune service interface:

```shell
curl -X POST --data-binary 'query=select * where {
?s a :Soul;
  p:name "Alice".
?s p:following ?f .} limit 10' https://your-neptune-endpoint:port/sparql
```

## To use Jena

For demonstration purposes, we will use [docker](https://www.docker.com/) to launch a Jena service:

```shell
docker run -p 3030:3030 -e ADMIN_PASSWORD=pw123 stain/jena-fuseki
```

If successful, please visit http://localhost:3030/ using the account "admin" and password "pw123".

1. First please create a dataset:

<figure><img src="https://2101283974-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYeYon1a8IZta2Zm96hF1%2Fuploads%2Fgit-blob-f34b0a811c0d96724dce01071c597ab229d1f8fe%2Fjena-1%20(1).png?alt=media" alt=""><figcaption><p>Figure 7-4 Add a dataset</p></figcaption></figure>

<figure><img src="https://2101283974-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYeYon1a8IZta2Zm96hF1%2Fuploads%2Fgit-blob-048b1c1ce63705392ae5000980f9f428306da76b%2Fjena-2%20(1)%20(2).png?alt=media" alt=""><figcaption><p>Figure 7-5 Create demo dataset</p></figcaption></figure>

2. Then import the data from the last step into the graph database.

```sparql
PREFIX : <http://relationlabs.ai/entity/>
PREFIX p: <http://relationlabs.ai/property/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe a :Soul;
    p:name "Alice" .

:Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e a :Soul;
    p:name "Bob" .

:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe p:following :Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e .
```

<figure><img src="https://2101283974-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYeYon1a8IZta2Zm96hF1%2Fuploads%2Fgit-blob-ce8d0ee4b671f69bd0622877afca3d1f9d6afead%2Fjena-3%20(1)%20(2).png?alt=media" alt=""><figcaption><p>Figure 7-6 Upload RDF data</p></figcaption></figure>

<figure><img src="https://2101283974-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYeYon1a8IZta2Zm96hF1%2Fuploads%2Fgit-blob-1065a94c116c037d411a7e055e184996dc523ed8%2Fjena-4%20(1)%20(3).png?alt=media" alt=""><figcaption><p>Figure 7-7 Select a file and upload</p></figcaption></figure>

3. Finally, switch to the Query tag to query which people Alice has followed:

```sparql
PREFIX : <http://relationlabs.ai/entity/>
PREFIX p: <http://relationlabs.ai/property/>

SELECT * WHERE {
  ?me a :Soul;
	p:name "Alice";
    p:following ?following .
  ?following p:name ?name .
}
LIMIT 10
```

<figure><img src="https://2101283974-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYeYon1a8IZta2Zm96hF1%2Fuploads%2Fgit-blob-0ab3237c1463cec391496e3b4a4c2d832497a099%2Fjena-5%20(1)%20(2).png?alt=media" alt=""><figcaption><p>Figure 7-8 Query with SPARQL</p></figcaption></figure>

<figure><img src="https://2101283974-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYeYon1a8IZta2Zm96hF1%2Fuploads%2Fgit-blob-4c87ebf1ac4721a4eeec29c077508901db296015%2Fjena-6%20(1).png?alt=media" alt=""><figcaption><p>Figure 7-9 Query result</p></figcaption></figure>

The query result is : Alice's address `0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe` followed Bob's address `0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e`.

## To use Neo4j

For demonstration purposes, we will use [docker](https://www.docker.com/) to launch a Neo4j service:

```shell
docker run \
    -p 7474:7474 -p 7687:7687 \
    --name neo4j-neosemantics \
    neo4j:5.5.0
```

1. Install plugins to support RDF

```shell
docker exec -it neo4j-neosemantics bash
cd plugins/
wget https://github.com/neo4j-labs/neosemantics/releases/download/5.5.0.0/neosemantics-5.5.0.0.jar
```

2. Configure Plugin

Open file: `conf/neo4j.conf` and append `dbms.unmanaged_extension_classes=n10s.endpoint=/rdf`.

then restart Neo4j Service:

```shell
docker restart neo4j-neosemantics
```

Open Neo4j Browser: http://localhost:7474/browser/ Default login is username 'neo4j' and password 'neo4j'.

3. Configure Graph

Execute the following commands in the Neo4j browser input box:

{% tabs %}
{% tab title="cypher-shell" %}
```cypher
CALL n10s.graphconfig.init();

CREATE CONSTRAINT n10s_unique_uri FOR (r:Resource) REQUIRE r.uri IS UNIQUE;

CALL n10s.graphconfig.init( {  handleMultival: "ARRAY" })

CALL n10s.nsprefixes.add("e", "http://relationlabs.ai/entity/");
CALL n10s.nsprefixes.add("p", "http://relationlabs.ai/property/");
```
{% endtab %}
{% endtabs %}

4. Importing RDF Data

Execute the following commands in the Neo4j browser input box:

{% tabs %}
{% tab title="cypher-shell" %}
```cypher
CALL n10s.rdf.import.inline("PREFIX : <http://relationlabs.ai/entity/>
PREFIX p: <http://relationlabs.ai/property/>
prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
prefix xsd: <http://www.w3.org/2001/XMLSchema#>
prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>

:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe a :Soul;
    p:name \"Alice\" .

:Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e a :Soul;
    p:name \"Bob\" .

:Soul_0x0109c8ee3151bde7b6b5d9f37e9d2c4bc16930fe p:following :Soul_0x6247123ec0fe0d25feb811e3c4d4a760c1f2e63e .","Turtle");
```
{% endtab %}
{% endtabs %}

5. Querying

Execute the following commands in the Neo4j browser input box:

{% tabs %}
{% tab title="cypher-shell" %}
```cypher
MATCH (ss:Resource {p__name: ["Alice"]})-[:p__following]->(oo) RETURN ss, oo
```
{% endtab %}
{% endtabs %}

<figure><img src="https://2101283974-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYeYon1a8IZta2Zm96hF1%2Fuploads%2Fgit-blob-af6c5c8489b40e97e02751aaf80beb10fd205de4%2Findexer-neo4j.png?alt=media" alt=""><figcaption><p>Figure 7-10 To use Neo4j</p></figcaption></figure>
