# Hyper-Modular Schema Structure

**Version**: 0.1.0  
**Date**: 2025-11-21  
**Schema**: Heritage Custodian Observation and Reconstruction Pattern

---

## Overview

The Heritage Custodian schema uses a **hyper-modular architecture** where every class, enum, and slot is defined in its own individual file. This provides maximum granularity for version control, parallel development, and maintainability.

**Total Files**: 78 YAML files
- **Classes**: 12 files (`modules/classes/`)
- **Enums**: 5 files (`modules/enums/`)
- **Slots**: 59 files (`modules/slots/`)
- **Core Modules**: 1 file (`metadata.yaml`)
- **Main Schema**: 1 file (`01_custodian_name_modular.yaml`)

**Note**: Aggregator files (`enums_all.yaml`, `slots_all.yaml`, `classes_all.yaml`) still exist but are not used by the main schema. They remain available for backward compatibility.

---

## Directory Structure

```
schemas/20251121/linkml/
├── 01_custodian_name_modular.yaml    # Main schema (directly imports all 76 modules)
├── HYPER_MODULAR_STRUCTURE.md        # This file
├── SLOT_NAMING_CONVENTIONS.md        # Slot naming rules for range variants
│
└── modules/
    ├── metadata.yaml                  # Schema metadata & namespace prefixes
    │
    ├── enums/                         # 5 enum definitions (all imported directly)
    │   ├── AgentTypeEnum.yaml
    │   ├── AppellationTypeEnum.yaml
    │   ├── LegalStatusEnum.yaml
    │   ├── ReconstructionActivityTypeEnum.yaml
    │   └── SourceDocumentTypeEnum.yaml
    │
    ├── slots/                         # 59 slot definitions (all imported directly)
    │   ├── id.yaml
    │   ├── created.yaml
    │   ├── modified.yaml
    │   ├── observed_name.yaml
    │   ├── was_revision_of.yaml      # May contain multiple range variants
    │   └── ... (54 more slot files)  # (see SLOT_NAMING_CONVENTIONS.md)
    │
    ├── classes/                       # 12 class definitions (all imported directly)
    │   ├── Custodian.yaml
    │   ├── CustodianObservation.yaml
    │   ├── CustodianName.yaml
    │   ├── CustodianReconstruction.yaml
    │   ├── ReconstructionActivity.yaml
    │   ├── Agent.yaml
    │   ├── Identifier.yaml
    │   ├── Appellation.yaml
    │   ├── SourceDocument.yaml
    │   ├── ConfidenceMeasure.yaml
    │   ├── LanguageCode.yaml
    │   └── TimeSpan.yaml
    │
    └── [Legacy aggregators - not used by main schema]
        ├── enums_all.yaml             # Aggregator for backward compatibility
        ├── slots_all.yaml             # Aggregator for backward compatibility
        └── classes_all.yaml           # Aggregator for backward compatibility
```

---

## Namespace Structure

All components use the `https://nde.nl/ontology/hc/` base namespace:

| Component | Namespace Pattern | Example |
|-----------|-------------------|---------|
| **Base** | `https://nde.nl/ontology/hc/` | Schema root |
| **Classes** | `https://nde.nl/ontology/hc/class/{ClassName}` | `https://nde.nl/ontology/hc/class/Custodian` |
| **Enums** | `https://nde.nl/ontology/hc/enum/{EnumName}` | `https://nde.nl/ontology/hc/enum/LegalStatusEnum` |
| **Slots** | `https://nde.nl/ontology/hc/slot/{slot_name}` | `https://nde.nl/ontology/hc/slot/was_revision_of` |
| **Metadata** | `https://nde.nl/ontology/hc/metadata` | Metadata module |

**Prefixes** (defined in `modules/metadata.yaml`):
```yaml
prefixes:
  hc: https://nde.nl/ontology/hc/
  hc_class: https://nde.nl/ontology/hc/class/
  hc_enum: https://nde.nl/ontology/hc/enum/
  hc_slot: https://nde.nl/ontology/hc/slot/
```

---

## Import Strategy

### Direct Import Pattern

The main schema **directly imports all 76 individual component files** for maximum transparency and granularity:

```yaml
# 01_custodian_name_modular.yaml

imports:
  - linkml:types
  - modules/metadata
  
  # Enums (5 files)
  - modules/enums/AgentTypeEnum
  - modules/enums/AppellationTypeEnum
  - modules/enums/LegalStatusEnum
  - modules/enums/ReconstructionActivityTypeEnum
  - modules/enums/SourceDocumentTypeEnum
  
  # Slots (59 files)
  - modules/slots/activity_type
  - modules/slots/affiliation
  # ... (57 more slot imports)
  
  # Classes (12 files)
  - modules/classes/Agent
  - modules/classes/Appellation
  # ... (10 more class imports)
```

**Benefits of Direct Imports**:
- ✅ **Complete Transparency**: Immediately see all schema dependencies
- ✅ **Explicit Dependencies**: No hidden imports through aggregators
- ✅ **Selective Imports**: Easy to comment out individual components for custom schemas
- ✅ **Better IDE Support**: Direct file references for navigation
- ✅ **Clear Audit Trail**: Git diffs show exactly which components changed

**Note**: Aggregator modules (`enums_all.yaml`, `slots_all.yaml`, `classes_all.yaml`) still exist for backward compatibility and can be used by downstream projects that prefer a simpler import structure.

---

## File Naming Conventions

### Class Files

**Pattern**: `{ClassName}.yaml` (PascalCase)

Examples:
- `Custodian.yaml`
- `CustodianObservation.yaml`
- `CustodianReconstruction.yaml`

**File structure**:
```yaml
id: https://nde.nl/ontology/hc/class/ClassName
name: ClassName
title: ClassName Class

imports:
  - linkml:types
  - OtherClass  # If needed

classes:
  ClassName:
    class_uri: ontology:Class
    description: "..."
    slots:
      - slot1
      - slot2
```

---

### Enum Files

**Pattern**: `{EnumName}.yaml` (PascalCase with "Enum" suffix)

Examples:
- `LegalStatusEnum.yaml`
- `AgentTypeEnum.yaml`

**File structure**:
```yaml
id: https://nde.nl/ontology/hc/enum/EnumName
name: EnumName

enums:
  EnumName:
    description: "..."
    permissible_values:
      VALUE1:
        description: "..."
      VALUE2:
        description: "..."
```

---

### Slot Files

**Pattern**: `{slot_name}.yaml` (snake_case)

Examples:
- `legal_name.yaml`
- `was_revision_of.yaml`
- `observed_name.yaml`

**Special Case - Range Variants**: See `SLOT_NAMING_CONVENTIONS.md` for handling multiple slots with the same ontological property but different ranges.

**File structure**:
```yaml
id: https://nde.nl/ontology/hc/slot/slot_name
name: slot-name-slot

imports:
  - ../classes/RangeClass  # If range is a class

slots:
  slot_name:
    slot_uri: ontology:property
    range: RangeType
    description: "..."
    
  # Optional: Range variants (same slot_uri, different range)
  slot_name-variant:
    slot_uri: ontology:property  # SAME as base
    range: DifferentRangeType
    description: "..."
```

---

## Maintenance Guidelines

### Adding a New Class

1. Create file: `modules/classes/{ClassName}.yaml`
2. Define class with namespace: `https://nde.nl/ontology/hc/class/{ClassName}`
3. Add import to `modules/classes_all.yaml`
4. Test schema generation: `gen-owl 01_custodian_name_modular.yaml`

### Adding a New Enum

1. Create file: `modules/enums/{EnumName}.yaml`
2. Define enum with namespace: `https://nde.nl/ontology/hc/enum/{EnumName}`
3. Add import to `modules/enums_all.yaml`
4. Test schema generation

### Adding a New Slot

1. **Check if ontologically related slot exists**: Look for existing slots with same `slot_uri`
2. **If EXISTS**: Add range variant to existing file (see `SLOT_NAMING_CONVENTIONS.md`)
3. **If NEW**: Create file `modules/slots/{slot_name}.yaml`
4. Define slot with namespace: `https://nde.nl/ontology/hc/slot/{slot_name}`
5. Add import to `modules/slots_all.yaml` (only if new file)
6. Test schema generation

### Adding a Range Variant to Existing Slot

**Example**: Adding `was_revision_of` for `Record` class

1. Open existing file: `modules/slots/was_revision_of.yaml`
2. Add import for new range class:
   ```yaml
   imports:
     - ../classes/CustodianReconstruction  # Existing
     - ../classes/Record                    # NEW
   ```
3. Add new slot variant:
   ```yaml
   slots:
     was_revision_of:
       slot_uri: prov:wasRevisionOf
       range: CustodianReconstruction
       description: "..."
     
     was_revision_of-record:  # NEW
       slot_uri: prov:wasRevisionOf
       range: Record
       description: "..."
   ```
4. **No change to aggregator needed** (file already imported)
5. Test schema generation

---

## Validation and Testing

### Validate Schema Structure

```bash
cd /Users/kempersc/apps/glam/schemas/20251121/linkml

# Test OWL generation (validates imports and structure)
gen-owl 01_custodian_name_modular.yaml > /dev/null

# Test JSON Schema generation
gen-json-schema 01_custodian_name_modular.yaml > /dev/null

# Test Python dataclasses generation
gen-python 01_custodian_name_modular.yaml > /dev/null
```

### Check Namespace Consistency

```bash
# All class files should have hc/class/ namespace
grep -h "^id:" modules/classes/*.yaml | sort -u

# All enum files should have hc/enum/ namespace
grep -h "^id:" modules/enums/*.yaml | sort -u

# All slot files should have hc/slot/ namespace
grep -h "^id:" modules/slots/*.yaml | sort -u
```

Expected output:
```
# Classes
https://nde.nl/ontology/hc/class/Agent
https://nde.nl/ontology/hc/class/Appellation
...

# Enums
https://nde.nl/ontology/hc/enum/AgentTypeEnum
https://nde.nl/ontology/hc/enum/AppellationTypeEnum
...

# Slots
https://nde.nl/ontology/hc/slot/activity_type
https://nde.nl/ontology/hc/slot/affiliation
...
```

---

## Benefits of Hyper-Modular Structure

### 1. Granular Version Control

Each component has independent git history:
```bash
git log modules/classes/Custodian.yaml
git blame modules/slots/legal_form.yaml
```

### 2. Parallel Development

Multiple developers can work simultaneously without merge conflicts:
- Developer A edits `CustodianObservation.yaml`
- Developer B edits `ReconstructionActivity.yaml`
- No conflicts, both changes merge cleanly

### 3. Selective Imports

Can create specialized schemas importing only needed components:
```yaml
# Mini schema for observations only
imports:
  - modules/metadata
  - modules/classes/CustodianObservation
  - modules/slots/observed_name
  - modules/slots/source
```

### 4. Clear Ownership

One file = one concept = one maintainer:
- `Custodian.yaml` → CIDOC-CRM expert
- `LegalStatusEnum.yaml` → GLEIF ontology expert
- `was_revision_of.yaml` → PROV-O expert

### 5. Easier Code Review

Small, focused pull requests:
- ❌ "Update schema with 5 new classes" (monolithic, 500 lines)
- ✅ "Add TimeSpan class" (one file, 96 lines)

### 6. Better Documentation

Each file can have extensive inline documentation without cluttering others:
```yaml
# CustodianReconstruction.yaml can have 200 lines of comments
# without making Identifier.yaml harder to read
```

### 7. IDE-Friendly

File tree navigation:
```
modules/classes/
  ├── Agent.yaml              ← Easy to find
  ├── Custodian.yaml          ← Alphabetically sorted
  └── CustodianObservation.yaml
```

vs. monolithic:
```
heritage_custodian.yaml:3458  ← Where is CustodianObservation?
```

---

## Migration from Consolidated Structure

### Phase 1: Module Consolidation (Completed)

- ✅ Split monolithic schema into 9 modules
- ✅ Classes grouped by function (base, observation, reconstruction, etc.)

### Phase 2: Hyper-Modularization (Completed 2025-11-21)

- ✅ Split all 12 classes into individual files
- ✅ Split all 5 enums into individual files
- ✅ Split all 59 slots into individual files
- ✅ Created 3 aggregator modules
- ✅ Updated all namespace URIs to `nde.nl/ontology/hc/`
- ✅ Validated OWL generation

### Legacy Files (Can Be Deleted)

These consolidated module files are now obsolete:
- `modules/base_classes.yaml` → Replaced by `classes/Custodian.yaml`
- `modules/observation_classes.yaml` → Replaced by `classes/CustodianObservation.yaml`, `classes/CustodianName.yaml`
- `modules/reconstruction_classes.yaml` → Replaced by `classes/CustodianReconstruction.yaml`
- `modules/provenance_classes.yaml` → Replaced by `classes/ReconstructionActivity.yaml`, `classes/Agent.yaml`
- `modules/supporting_classes.yaml` → Replaced by 6 individual class files
- `modules/enums.yaml` → Replaced by `enums_all.yaml` + 5 individual files
- `modules/slots.yaml` → Replaced by `slots_all.yaml` + 59 individual files

---

## Troubleshooting

### Error: "Cannot find module X"

**Cause**: Import path incorrect or file missing

**Solution**:
1. Check aggregator imports correct file name
2. Verify file exists: `ls modules/classes/X.yaml`
3. Check `id:` in file matches import path

### Error: "Duplicate class definition"

**Cause**: Class defined in multiple files and both imported

**Solution**:
1. Remove class from old consolidated module
2. Ensure aggregator imports new individual file only

### Warning: "Multiple owl types"

**Cause**: Range conflicts (e.g., slot used as both object property and datatype property)

**Solution**: Expected for polymorphic slots with `any_of`. Can be ignored if intentional.

---

## References

- **Slot Naming Conventions**: `SLOT_NAMING_CONVENTIONS.md`
- **LinkML Documentation**: https://linkml.io/
- **Schema Validation**: `gen-owl`, `gen-json-schema`, `gen-python`
- **Main Schema**: `01_custodian_name_modular.yaml`

---

**Last Updated**: 2025-11-21  
**Maintainer**: GLAM Data Extraction Project