Working with Connections

Connections in EngramDB allow you to create graph-like relationships between memory nodes. This document explains how to work with connections effectively.

What are Connections?

A connection represents a relationship between two memory nodes. Each connection has:

A target memory node ID (the node being connected to)
A relationship type (e.g., Association, Causation, Sequence)
A strength value (between 0.0 and 1.0)
A creation timestamp

Connections enable EngramDB to model complex relationships between memories, forming a knowledge graph that can be traversed and queried.

Relationship Types

EngramDB provides several built-in relationship types:

Association: A general relationship between related concepts
Causation: A cause-effect relationship
Sequence: A temporal sequence or ordering
Hierarchy: A parent-child or category-subcategory relationship
Similarity: Indicates that two memories are similar
Opposition: Indicates that two memories are opposites or contradictory
Custom: User-defined relationship types

Creating Connections

You can create connections between memory nodes in two ways:

Directly on a memory node
Through the database API

Using the Memory Node API

Rust Example

use engramdb::{MemoryNode, RelationshipType};
use engramdb::core::Connection;
use uuid::Uuid;

// Create two memory nodes
let mut memory1 = MemoryNode::new(vec![0.1, 0.2, 0.3, 0.4]);
let memory2 = MemoryNode::new(vec![0.2, 0.3, 0.4, 0.5]);

// Save them to get their IDs
let memory1_id = db.save(&memory1)?;
let memory2_id = db.save(&memory2)?;

// Create a connection from memory1 to memory2
let connection = Connection::new(
    memory2_id,
    RelationshipType::Association,
    0.75
);

// Load memory1 again to update it
let mut memory1 = db.load(memory1_id)?;
memory1.add_connection(connection);

// Save the updated memory1
db.save(&memory1)?;

Python Example

import engramdb
import numpy as np

# Create two memory nodes
memory1 = engramdb.MemoryNode(np.array([0.1, 0.2, 0.3, 0.4], dtype=np.float32))
memory2 = engramdb.MemoryNode(np.array([0.2, 0.3, 0.4, 0.5], dtype=np.float32))

# Save them to get their IDs
memory1_id = db.save(memory1)
memory2_id = db.save(memory2)

# Create a connection from memory1 to memory2
connection = engramdb.Connection(
    memory2_id,
    engramdb.RelationshipType.ASSOCIATION,
    0.75
)

# Load memory1 again to update it
memory1 = db.load(memory1_id)
memory1.add_connection(connection)

# Save the updated memory1
db.save(memory1)

Using the Database API

Rust Example

use engramdb::{Database, RelationshipType};

// Assuming memory1_id and memory2_id are valid UUIDs of existing memories
db.add_connection(
    memory1_id,
    memory2_id,
    RelationshipType::Causation,
    0.9
)?;

Python Example

# Assuming memory1_id and memory2_id are valid UUIDs of existing memories
db.add_connection(
    memory1_id,
    memory2_id,
    engramdb.RelationshipType.CAUSATION,
    0.9
)

Retrieving Connections

You can retrieve the connections of a memory node in two ways:

Directly from a memory node
Through the database API

Using the Memory Node API

Rust Example

// Load a memory node
let memory = db.load(memory_id)?;

// Get all connections
let connections = memory.connections();
println!("Memory has {} connections", connections.len());

// Examine each connection
for connection in connections {
    println!("Connected to: {}", connection.target_id());
    println!("Relationship type: {:?}", connection.relationship_type());
    println!("Strength: {:.2}", connection.strength());
    println!("Created at: {}", connection.creation_timestamp());
}

Python Example

# Load a memory node
memory = db.load(memory_id)

# Get all connections
connections = memory.connections()
print(f"Memory has {len(connections)} connections")

# Examine each connection
for connection in connections:
    print(f"Connected to: {connection.target_id()}")
    print(f"Relationship type: {connection.relationship_type()}")
    print(f"Strength: {connection.strength():.2f}")
    print(f"Created at: {connection.creation_timestamp()}")

Using the Database API

Rust Example

// Get connections for a memory
let connections = db.get_connections(memory_id)?;

println!("Connections for memory {}:", memory_id);
for connection in connections {
    println!("Connected to: {}", connection.target_id);
    println!("Relationship type: {}", connection.type_name);
    println!("Strength: {:.2}", connection.strength);

    // Load the target memory to get more information
    let target = db.load(connection.target_id)?;
    // ... work with the target memory
}

Python Example

# Get connections for a memory
connections = db.get_connections(memory_id)

print(f"Connections for memory {memory_id}:")
for connection in connections:
    print(f"Connected to: {connection.target_id}")
    print(f"Relationship type: {connection.type_name}")
    print(f"Strength: {connection.strength:.2f}")

    # Load the target memory to get more information
    target = db.load(connection.target_id)
    # ... work with the target memory

Removing Connections

You can remove connections in two ways:

Directly from a memory node
Through the database API

Using the Memory Node API

Rust Example

// Load a memory node
let mut memory = db.load(memory_id)?;

// Remove a connection to a specific target
let removed = memory.remove_connection(target_id);
if removed {
    println!("Connection removed");

    // Save the updated memory
    db.save(&memory)?;
} else {
    println!("No connection found to that target");
}

Python Example

# Load a memory node
memory = db.load(memory_id)

# Remove a connection to a specific target
removed = memory.remove_connection(target_id)
if removed:
    print("Connection removed")

    # Save the updated memory
    db.save(memory)
else:
    print("No connection found to that target")

Using the Database API

Rust Example

// Remove a connection between two memories
let removed = db.remove_connection(source_id, target_id)?;
if removed {
    println!("Connection removed");
} else {
    println!("No connection found between those memories");
}

Python Example

# Remove a connection between two memories
removed = db.remove_connection(source_id, target_id)
if removed:
    print("Connection removed")
else:
    print("No connection found between those memories")

Use Cases for Connections

Knowledge Graphs

Connections can be used to build knowledge graphs that represent relationships between concepts.

// Create memory nodes for concepts
let mut apple = MemoryNode::new(vec![0.1, 0.2, 0.3, 0.4]);
apple.set_attribute("concept".to_string(), AttributeValue::String("Apple".to_string()));

let mut fruit = MemoryNode::new(vec![0.2, 0.3, 0.4, 0.5]);
fruit.set_attribute("concept".to_string(), AttributeValue::String("Fruit".to_string()));

let mut red = MemoryNode::new(vec![0.3, 0.4, 0.5, 0.6]);
red.set_attribute("concept".to_string(), AttributeValue::String("Red".to_string()));

// Save them
let apple_id = db.save(&apple)?;
let fruit_id = db.save(&fruit)?;
let red_id = db.save(&red)?;

// Create connections
db.add_connection(apple_id, fruit_id, RelationshipType::Hierarchy, 0.9)?; // Apple is a fruit
db.add_connection(apple_id, red_id, RelationshipType::Association, 0.7)?; // Apples are associated with red

Causal Chains

Connections can represent cause-effect relationships, forming causal chains.

# Create memory nodes for events
event1 = engramdb.MemoryNode(np.random.rand(4).astype(np.float32))
event1.set_attribute("event", "Rain")

event2 = engramdb.MemoryNode(np.random.rand(4).astype(np.float32))
event2.set_attribute("event", "Wet ground")

event3 = engramdb.MemoryNode(np.random.rand(4).astype(np.float32))
event3.set_attribute("event", "Slippery surface")

event4 = engramdb.MemoryNode(np.random.rand(4).astype(np.float32))
event4.set_attribute("event", "Fall")

# Save them
event1_id = db.save(event1)
event2_id = db.save(event2)
event3_id = db.save(event3)
event4_id = db.save(event4)

# Create a causal chain
db.add_connection(event1_id, event2_id, engramdb.RelationshipType.CAUSATION, 0.9)
db.add_connection(event2_id, event3_id, engramdb.RelationshipType.CAUSATION, 0.8)
db.add_connection(event3_id, event4_id, engramdb.RelationshipType.CAUSATION, 0.7)

Temporal Sequences

Connections can represent sequences of events or steps.

// Create memory nodes for steps in a process
let mut step1 = MemoryNode::new(vec![0.1, 0.2, 0.3, 0.4]);
step1.set_attribute("step".to_string(), AttributeValue::String("Prepare ingredients".to_string()));

let mut step2 = MemoryNode::new(vec![0.2, 0.3, 0.4, 0.5]);
step2.set_attribute("step".to_string(), AttributeValue::String("Mix batter".to_string()));

let mut step3 = MemoryNode::new(vec![0.3, 0.4, 0.5, 0.6]);
step3.set_attribute("step".to_string(), AttributeValue::String("Bake in oven".to_string()));

let mut step4 = MemoryNode::new(vec![0.4, 0.5, 0.6, 0.7]);
step4.set_attribute("step".to_string(), AttributeValue::String("Cool and serve".to_string()));

// Save them
let step1_id = db.save(&step1)?;
let step2_id = db.save(&step2)?;
let step3_id = db.save(&step3)?;
let step4_id = db.save(&step4)?;

// Create a sequence
db.add_connection(step1_id, step2_id, RelationshipType::Sequence, 1.0)?;
db.add_connection(step2_id, step3_id, RelationshipType::Sequence, 1.0)?;
db.add_connection(step3_id, step4_id, RelationshipType::Sequence, 1.0)?;

Graph Traversal

You can traverse the graph by following connections from one memory to another.

Rust Example

// Start with a memory node
let start_id = some_memory_id;
let mut visited = std::collections::HashSet::new();
let mut queue = std::collections::VecDeque::new();
queue.push_back(start_id);

// Breadth-first traversal
while let Some(current_id) = queue.pop_front() {
    if visited.contains(&current_id) {
        continue;
    }

    visited.insert(current_id);

    // Process the current node
    let memory = db.load(current_id)?;
    println!("Visiting memory: {}", current_id);

    // Get all connections
    let connections = db.get_connections(current_id)?;

    // Add connected nodes to the queue
    for connection in connections {
        if !visited.contains(&connection.target_id) {
            queue.push_back(connection.target_id);
        }
    }
}

println!("Visited {} memories", visited.len());

Python Example

import collections

# Start with a memory node
start_id = some_memory_id
visited = set()
queue = collections.deque([start_id])

# Breadth-first traversal
while queue:
    current_id = queue.popleft()
    if current_id in visited:
        continue

    visited.add(current_id)

    # Process the current node
    memory = db.load(current_id)
    print(f"Visiting memory: {current_id}")

    # Get all connections
    connections = db.get_connections(current_id)

    # Add connected nodes to the queue
    for connection in connections:
        if connection.target_id not in visited:
            queue.append(connection.target_id)

print(f"Visited {len(visited)} memories")

Best Practices

When to Use Connections

Use connections when:

You need to represent explicit relationships between memories
You want to build a knowledge graph
You need to model causal chains or sequences
You want to represent hierarchical relationships

Connection Strength

The strength value (0.0 to 1.0) can be used to represent:

The confidence in the relationship
The importance of the relationship
The strength of association between concepts

Use consistent semantics for strength values across your application.

Bidirectional Relationships

If you need bidirectional relationships, you must create two connections:

// Create a bidirectional relationship
db.add_connection(node1_id, node2_id, RelationshipType::Association, 0.8)?;
db.add_connection(node2_id, node1_id, RelationshipType::Association, 0.8)?;

Custom Relationship Types

You can extend the built-in relationship types with custom ones:

// Define a custom relationship type
let custom_type = RelationshipType::Custom("Ingredient".to_string());

// Use it in a connection
db.add_connection(recipe_id, ingredient_id, custom_type, 1.0)?;

Conclusion

Connections are a powerful feature of EngramDB that enable modeling complex relationships between memories. By effectively using connections, you can build rich knowledge graphs, causal chains, and temporal sequences that enhance the capabilities of your agent systems.

Getting Started

API Reference

Examples

Advanced Topics

Contributing

​Working with Connections

​What are Connections?

​Relationship Types

​Creating Connections

​Using the Memory Node API

​Rust Example

​Python Example

​Using the Database API

​Rust Example

​Python Example

​Retrieving Connections

​Using the Memory Node API

​Rust Example

​Python Example

​Using the Database API

​Rust Example

​Python Example

​Removing Connections

​Using the Memory Node API

​Rust Example

​Python Example

​Using the Database API

​Rust Example

​Python Example

​Use Cases for Connections

​Knowledge Graphs

​Causal Chains

​Temporal Sequences

​Graph Traversal

​Rust Example

​Python Example

​Best Practices

​When to Use Connections

​Connection Strength

​Bidirectional Relationships

​Custom Relationship Types

​Conclusion

Working with Connections

What are Connections?

Relationship Types

Creating Connections

Using the Memory Node API

Rust Example

Python Example

Using the Database API

Rust Example

Python Example

Retrieving Connections

Using the Memory Node API

Rust Example

Python Example

Using the Database API

Rust Example

Python Example

Removing Connections

Using the Memory Node API

Rust Example

Python Example

Using the Database API

Rust Example

Python Example

Use Cases for Connections

Knowledge Graphs

Causal Chains

Temporal Sequences

Graph Traversal

Rust Example

Python Example

Best Practices

When to Use Connections

Connection Strength

Bidirectional Relationships

Custom Relationship Types

Conclusion