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