mirror of
https://github.com/semantica-agi/semantica.git
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169 lines
4.5 KiB
Markdown
169 lines
4.5 KiB
Markdown
# Triplet Store
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> **Store and query RDF triplets with SPARQL support and semantic reasoning using industry-standard triplet stores.**
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---
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## 🎯 Overview
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<div class="grid cards" markdown>
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- :material-graph-outline:{ .lg .middle } **RDF Storage**
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---
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Store subject-predicate-object triplets in W3C-compliant RDF format
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- :material-code-braces:{ .lg .middle } **SPARQL Queries**
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---
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Full W3C SPARQL 1.1 query language support for powerful semantic queries
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- :material-brain:{ .lg .middle } **Reasoning**
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---
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RDFS and OWL reasoning for inference and knowledge discovery
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- :material-database-sync:{ .lg .middle } **Multiple Backends**
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---
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Blazegraph, Apache Jena, and RDF4J support
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- :material-link-variant:{ .lg .middle } **Federation**
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---
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Query across multiple triplet stores with SPARQL federation
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- :material-upload-multiple:{ .lg .middle } **Bulk Loading**
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---
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High-performance bulk data loading with progress tracking
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</div>
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!!! tip "Choosing the Right Backend"
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- **Blazegraph**: High-performance, excellent for large datasets, GPU acceleration
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- **Apache Jena**: Full-featured, TDB2 storage, SHACL validation
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- **RDF4J**: Java-based, excellent tooling, multiple storage backends
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---
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## ⚙️ Algorithms Used
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### Query Algorithms
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- **SPARQL Query Optimization**: Join reordering with selectivity estimation
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- **Triplet Pattern Matching**: Index-based lookup with B+ trees
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- **Graph Pattern Matching**: Subgraph isomorphism with backtracking
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- **Query Planning**: Cost-based optimization with statistics
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- **Join Algorithms**: Hash join, merge join, nested loop join
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- **Filter Pushdown**: Early filter application for performance
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### Indexing
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- **SPO Index**: Subject-Predicate-Object index for subject lookups
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- **POS Index**: Predicate-Object-Subject index for predicate lookups
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- **OSP Index**: Object-Subject-Predicate index for object lookups
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- **Six-Index Scheme**: All permutations (SPO, SOP, PSO, POS, OSP, OPS) for optimal query performance
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- **B+ Tree Indexing**: Efficient range queries and sorted access
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- **Hash Indexing**: O(1) exact match lookups
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### Reasoning Algorithms
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- **RDFS Reasoning**: Subclass/subproperty inference, domain/range inference
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- **OWL Reasoning**: Class hierarchy, property characteristics, cardinality constraints
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- **Forward Chaining**: Materialization of inferred triplets
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- **Backward Chaining**: On-demand inference during query execution
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- **Rule-Based Inference**: Custom SWRL rules
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### Bulk Loading
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- **Batch Processing**: Chunked triplet insertion with configurable batch size
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- **Parallel Loading**: Multi-threaded data loading
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- **Index Building**: Deferred index construction for faster loading
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- **Transaction Management**: Atomic batch commits with rollback support
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---
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## Main Classes
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### TripletStore
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Main interface for triplet store operations.
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**Methods:**
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| Method | Description | Algorithm |
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|--------|-------------|-----------|
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| `__init__(backend, endpoint)` | Initialize triplet store | Factory pattern |
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| `add_triplet(triplet)` | Add single triplet | Single insert |
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| `add_triplets(triplets, batch_size)` | Add multiple triplets | Bulk load with batching |
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| `get_triplets(s, p, o)` | Retrieve triplets | Pattern matching |
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| `delete_triplet(triplet)` | Delete triplet | Pattern matching deletion |
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| `execute_query(query)` | Execute SPARQL | Query engine delegation |
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### BulkLoader
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High-volume data loading utility.
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**Methods:**
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| Method | Description | Algorithm |
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|--------|-------------|-----------|
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| `load_triplets(triplets, store)` | Bulk load triplets | Batch processing with retries |
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### QueryEngine
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SPARQL query execution and optimization engine.
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**Methods:**
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| Method | Description | Algorithm |
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|--------|-------------|-----------|
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| `execute(query)` | Execute SPARQL query | Query execution |
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| `optimize(query)` | Optimize SPARQL query | Query rewriting |
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---
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## 🚀 Usage
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### Initialization
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```python
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from semantica.triplet_store import TripletStore
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# Initialize Blazegraph store
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store = TripletStore(
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backend="blazegraph",
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endpoint="http://localhost:9999/blazegraph"
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)
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```
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### Adding Data
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```python
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from semantica.semantic_extract.triplet_extractor import Triplet
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# Single triplet
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triplet = Triplet("http://s", "http://p", "http://o")
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store.add_triplet(triplet)
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# Bulk load
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triplets = [Triplet(f"http://s{i}", "http://p", "http://o") for i in range(1000)]
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store.add_triplets(triplets)
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```
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### Querying
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```python
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query = """
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SELECT ?s ?p ?o
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WHERE {
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?s ?p ?o
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}
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LIMIT 10
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"""
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results = store.execute_query(query)
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```
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