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