trustgraph/docs/tech-specs/structured_data_schemas.md
2025-08-21 14:50:57 +01:00

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# Structured Data Pulsar Schema Changes
## Overview
Based on the STRUCTURED_DATA.md specification, this document proposes the necessary Pulsar schema additions and modifications to support structured data capabilities in TrustGraph.
## Required Schema Changes
### 1. Core Schema Enhancements
#### Enhanced Field Definition
The existing `Field` class in `core/primitives.py` needs additional properties:
```python
class Field(Record):
name = String()
type = String() # int, string, long, bool, float, double, timestamp
size = Integer()
primary = Boolean()
description = String()
# NEW FIELDS:
required = Boolean() # Whether field is required
enum_values = Array(String()) # For enum type fields
indexed = Boolean() # Whether field should be indexed
```
### 2. New Knowledge Schemas
#### 2.1 Structured Data Submission
New file: `knowledge/structured.py`
```python
from pulsar.schema import Record, String, Bytes, Map
from ..core.metadata import Metadata
class StructuredDataSubmission(Record):
metadata = Metadata()
format = String() # "json", "csv", "xml"
schema_name = String() # Reference to schema in config
data = Bytes() # Raw data to ingest
options = Map(String()) # Format-specific options
```
### 3. New Service Schemas
#### 3.1 NLP to Structured Query Service
New file: `services/nlp_query.py`
```python
from pulsar.schema import Record, String, Array, Map, Integer, Double
from ..core.primitives import Error
class NLPToStructuredQueryRequest(Record):
natural_language_query = String()
max_results = Integer()
context_hints = Map(String()) # Optional context for query generation
class NLPToStructuredQueryResponse(Record):
error = Error()
graphql_query = String() # Generated GraphQL query
variables = Map(String()) # GraphQL variables if any
detected_schemas = Array(String()) # Which schemas the query targets
confidence = Double()
```
#### 3.2 Structured Query Service
New file: `services/structured_query.py`
```python
from pulsar.schema import Record, String, Map, Array
from ..core.primitives import Error
class StructuredQueryRequest(Record):
query = String() # GraphQL query
variables = Map(String()) # GraphQL variables
operation_name = String() # Optional operation name for multi-operation documents
class StructuredQueryResponse(Record):
error = Error()
data = String() # JSON-encoded GraphQL response data
errors = Array(String()) # GraphQL errors if any
```
#### 2.2 Object Extraction Output
New file: `knowledge/object.py`
```python
from pulsar.schema import Record, String, Map, Double
from ..core.metadata import Metadata
class ExtractedObject(Record):
metadata = Metadata()
schema_name = String() # Which schema this object belongs to
values = Map(String()) # Field name -> value
confidence = Double()
source_span = String() # Text span where object was found
```
### 4. Enhanced Knowledge Schemas
#### 4.1 Object Embeddings Enhancement
Update `knowledge/embeddings.py` to support structured object embeddings better:
```python
class StructuredObjectEmbedding(Record):
metadata = Metadata()
vectors = Array(Array(Double()))
schema_name = String()
object_id = String() # Primary key value
field_embeddings = Map(Array(Double())) # Per-field embeddings
```
## Integration Points
### Flow Integration
The schemas will be used by new flow modules:
- `trustgraph-flow/trustgraph/decoding/structured` - Uses StructuredDataSubmission
- `trustgraph-flow/trustgraph/query/nlp_query/cassandra` - Uses NLP query schemas
- `trustgraph-flow/trustgraph/query/objects/cassandra` - Uses structured query schemas
- `trustgraph-flow/trustgraph/extract/object/row/` - Consumes Chunk, produces ExtractedObject
- `trustgraph-flow/trustgraph/storage/objects/cassandra` - Uses Rows schema
- `trustgraph-flow/trustgraph/embeddings/object_embeddings/qdrant` - Uses object embedding schemas
## Implementation Notes
1. **Schema Versioning**: Consider adding a `version` field to RowSchema for future migration support
2. **Type System**: The `Field.type` should support all Cassandra native types
3. **Batch Operations**: Most services should support both single and batch operations
4. **Error Handling**: Consistent error reporting across all new services
5. **Backwards Compatibility**: Existing schemas remain unchanged except for minor Field enhancements
## Next Steps
1. Implement schema files in the new structure
2. Update existing services to recognize new schema types
3. Implement flow modules that use these schemas
4. Add gateway/rev-gateway endpoints for new services
5. Create unit tests for schema validation