ln-723-mockdata-migrator
Type: L3 Worker Category: 7XX Project Bootstrap Parent: ln-720-structure-migrator
Migrates mock data from ORM schemas to.NET MockData classes with realistic sample data.
Purpose & Scope
| Aspect | Description |
|---|
| Input | ORM schema files (Drizzle, Prisma, TypeORM) |
| Output | C# MockData static classes |
| Primary ORM | Drizzle (others supported) |
Scope boundaries:
- Parses ORM schema definitions
- Generates C# entities and MockData classes
- Creates realistic sample data
- Does not generate database migrations or EF Core configs
Workflow
| Phase | Name | Actions | Output |
|---|
| 1 | Parse Schema | Read ORM file, extract table definitions | Entity model |
| 2 | Map Types | Apply type mapping rules, detect nullable | C# type definitions |
| 3 | Generate MockData | Create static class, generate sample data | MockData.cs files |
| 4 | Verify | Compile check, relationship validation | Valid C# code |
Phase 1: Parse Schema
Extract entity definitions from ORM schema.
| Step | Action | Reference |
|---|
| 1.1 | Locate schema file(s) | — |
| 1.2 | Identify ORM type (Drizzle/Prisma/TypeORM) | Detect by syntax |
| 1.3 | Extract table definitions | drizzle_patterns.md |
| 1.4 | Extract column definitions | drizzle_patterns.md |
| 1.5 | Identify constraints (PK, FK, nullable) | drizzle_patterns.md |
| 1.6 | Extract enum definitions | drizzle_patterns.md |
Output: Entity model with columns, types, and constraints.
Phase 2: Map Types
Convert ORM types to C# types.
| Step | Action | Reference |
|---|
| 2.1 | Map column types to C# | type_mapping.md |
| 2.2 | Determine nullable status | type_mapping.md |
| 2.3 | Identify primary keys | type_mapping.md |
| 2.4 | Map foreign keys | relationship_mapping.md |
| 2.5 | Transform names (snake_case → PascalCase) | drizzle_patterns.md |
Type mapping summary:
| ORM Type | C# Type | Nullable Rule |
|---|
| uuid | Guid | No (PK), Depends (FK) |
| varchar | string | Check.notNull() |
| integer | int | No |
| boolean | bool | No |
| timestamp | DateTime | Depends |
Phase 3: Generate MockData
Create C# MockData class with sample data.
| Step | Action | Reference |
|---|
| 3.1 | Create MockData class | data_generation.md |
| 3.2 | Generate GUIDs for entities | data_generation.md |
| 3.3 | Generate sample data per field | data_generation.md |
| 3.4 | Ensure FK relationships valid | relationship_mapping.md |
| 3.5 | Create accessor methods | data_generation.md |
Generation order by dependency:
| Order | Entity Type | Generate After |
|---|
| 1 | Root entities (no FK) | First |
| 2 | First-level children | Parents exist |
| 3 | Second-level children | Grandparents exist |
| N | Deepest children | All ancestors exist |
Phase 4: Verify
Validate generated code.
| Check | Method | Expected |
|---|
| Syntax valid | Compile check | No errors |
| FKs valid | Cross-reference | All FKs point to existing IDs |
| Types correct | Type analysis | Proper C# types |
| Names follow convention | Pattern check | PascalCase |
Supported ORM Detection
| ORM | Detection Pattern |
|---|
| Drizzle | pgTable(), mysqlTable(), sqliteTable() |
| Prisma | model X { syntax |
| TypeORM | @Entity(), @Column() decorators |
Entity Transformation Rules
| Source | Target | Transformation |
|---|
| Table name (plural, snake) | Class name (singular, Pascal) | user_profiles → UserProfile |
| Column name (snake) | Property name (Pascal) | created_at → CreatedAt |
| Enum name | Enum type (Pascal) | status_enum → StatusEnum |
| FK column | Navigation property | user_id → UserId |
MockData Class Structure
| Component | Purpose |
|---|
| Private static list | Holds immutable mock data |
| GetAll() method | Returns full list as IEnumerable |
| GetById(Guid id) | Finds single entity by ID |
| GetBy{FK}Id(Guid id) | Filters by foreign key |
Sample Data Guidelines
| Field Type | Sample Count | Distribution |
|---|
| Root entities | 3-5 items | Varied status/priority |
| Child entities | 5-10 items | Distributed across parents |
| Leaf entities | 10-20 items | Realistic variety |
Critical Rules
- Single Responsibility: Generate only MockData, no database code
- Idempotent: Can re-run to regenerate
- Valid Relationships: All FKs must reference existing parent IDs
- Realistic Data: Use domain-appropriate values, not random strings
- Generation Order: Parents before children
- Consistent GUIDs: Use fixed GUIDs for reproducibility
Definition of Done
- Schema file parsed successfully
- All tables/entities extracted
- Type mappings applied correctly
- MockData class generated per feature/entity group
- Sample data includes 5-10 items per entity
- Foreign keys reference valid parent IDs
- Accessor methods generated (GetAll, GetById)
- Code compiles without errors
Risk Mitigation
| Risk | Detection | Mitigation |
|---|
| Parse failure | Exception during parse | Support multiple schema formats |
| Invalid type mapping | Unknown ORM type | Log warning, use string as fallback |
| FK mismatch | FK references non-existent ID | Generate parents first, validate after |
| Name collision | Duplicate class names | Prefix with feature name |
| Circular references | Self-referencing with cycles | Limit depth, validate graph |
Reference Files
| File | Purpose |
|---|
references/type_mapping.md | ORM to C# type conversion rules |
references/drizzle_patterns.md | Drizzle schema parsing patterns |
references/data_generation.md | Realistic sample data patterns |
references/relationship_mapping.md | FK handling and generation order |
Version: 2.0.0 Last Updated: 2026-01-10
