Visual Data Flow 10. Neo4j .

Here are three examples of Neo4j code, along with qualitative and technical explanations for each:

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Example 1: Creating Nodes and Relationships

Qualitative Explanation:

1. Purpose: Create nodes and relationships to represent entities and their connections.

2. Use Case: Building a graph database for social networks, recommendation systems, or knowledge graphs.

3. Outcome: A graph structure that can be queried for insights.

Technical Explanation:

1. Create Nodes: Define nodes with labels and properties.

    CREATE (a:Person {name: "Alice", age: 30})
    CREATE (b:Person {name: "Bob", age: 25})
   

2. Create Relationships: Establish relationships between nodes.

    CREATE (a)-[:KNOWS]->(b)
   

3. Query Graph: Retrieve nodes and relationships.

    MATCH (a:Person)-[:KNOWS]->(b:Person) RETURN a, b
   

4. Output: Visualize or export the graph structure.

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Example 2: Querying a Graph

Qualitative Explanation:

1. Purpose: Query the graph to extract specific information.

2. Use Case: Finding connections, paths, or patterns in a graph.

3. Outcome: A result set containing the queried data.

Technical Explanation:

1. Match Nodes: Find nodes with specific labels or properties.

    MATCH (p:Person {name: "Alice"}) RETURN p
   

2. Traverse Relationships: Follow relationships to connected nodes.

    MATCH (a:Person)-[:KNOWS]->(b:Person) RETURN a, b
   

3. Filter Results: Apply conditions to filter results.

    MATCH (p:Person) WHERE p.age > 25 RETURN p
   

4. Aggregate Data: Perform aggregations like counting or summing.

    MATCH (p:Person) RETURN COUNT(p) AS total_people
   

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Example 3: Updating and Deleting Data

Qualitative Explanation:

1. Purpose: Modify or remove nodes and relationships in the graph.

2. Use Case: Maintaining up-to-date data in a dynamic graph database.

3. Outcome: An updated graph structure reflecting changes.

Technical Explanation:

1. Update Node Properties: Modify properties of existing nodes.

    MATCH (p:Person {name: "Alice"}) SET p.age = 31 RETURN p
   

2. Delete Relationships: Remove relationships between nodes.

    MATCH (a:Person {name: "Alice"})-[r:KNOWS]->(b:Person {name: "Bob"}) DELETE r
   

3. Delete Nodes: Remove nodes from the graph.

    MATCH (p:Person {name: "Bob"}) DELETE p
   

4. Batch Operations: Perform multiple updates or deletions in a single query.

    MATCH (p:Person) WHERE p.age < 30 DELETE p
   

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Input and Output Examples

Example 1: Creating Nodes and Relationships

• Input: None (programmatically defined).

• Output:

    Nodes: Alice, Bob
    Relationship: Alice KNOWS Bob
  

Example 2: Querying a Graph

• Input:

    Nodes: Alice (age 30), Bob (age 25)
    Relationship: Alice KNOWS Bob
  

• Output:

    Query: MATCH (a:Person)-[:KNOWS]->(b:Person) RETURN a, b
    Result: Alice, Bob
  

Example 3: Updating and Deleting Data

• Input:

    Nodes: Alice (age 30), Bob (age 25)
    Relationship: Alice KNOWS Bob
  

• Output:

    Updated Node: Alice (age 31)
    Deleted Relationship: Alice KNOWS Bob
    Deleted Node: Bob
  

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