neo/CUSTOM_MIGRATIONS_IMPLEMENTATION.md

Custom Migrations Implementation

Overview

This implementation adds a database-stored migration system for dynamically created objects. Migrations are recorded in a custom_migrations table in each tenant database, allowing them to be replayed or used for environment replication in the future.

Architecture

Components

1. CustomMigrationService

Location: backend/src/migration/custom-migration.service.ts

Handles all migration-related operations:

• generateCreateTableSQL(tableName, fields) - Generates SQL for creating object tables with standard fields
• createMigrationRecord() - Stores migration metadata in the database
• executeMigration() - Executes a pending migration and updates its status
• createAndExecuteMigration() - Creates and immediately executes a migration
• getMigrations() - Retrieves migration history with filtering
• ensureMigrationsTable() - Ensures the custom_migrations table exists

2. MigrationModule

Location: backend/src/migration/migration.module.ts

Provides the CustomMigrationService to other modules.

3. Updated ObjectService

Location: backend/src/object/object.service.ts

• Injects CustomMigrationService
• Calls createAndExecuteMigration() when a new object is created
• Generates table creation migrations with standard fields

Database Schema

custom_migrations Table

CREATE TABLE custom_migrations (
  id UUID PRIMARY KEY,
  tenantId UUID NOT NULL,
  name VARCHAR(255) NOT NULL,
  description TEXT,
  type ENUM('create_table', 'add_column', 'alter_column', 'add_index', 'drop_table', 'custom'),
  sql TEXT NOT NULL,
  status ENUM('pending', 'executed', 'failed') DEFAULT 'pending',
  executedAt TIMESTAMP NULL,
  error TEXT,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  INDEX idx_tenantId (tenantId),
  INDEX idx_status (status),
  INDEX idx_created_at (created_at)
)

Generated Object Tables

When a new object is created (e.g., "Account"), a table is automatically created with:

CREATE TABLE accounts (
  id VARCHAR(36) PRIMARY KEY,
  ownerId VARCHAR(36),
  name VARCHAR(255),
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  -- Custom fields added here
)

Standard Fields:

• id - UUID primary key
• ownerId - User who owns the record
• name - Primary name field
• created_at - Record creation timestamp
• updated_at - Record update timestamp

Field Type Mapping

Custom fields are mapped to SQL column types:

Field Type	SQL Type	Notes
TEXT, STRING	VARCHAR(255)
LONG_TEXT	TEXT	Large text content
NUMBER, DECIMAL	DECIMAL(18, 2)
INTEGER	INT
BOOLEAN	BOOLEAN	Defaults to FALSE
DATE	DATE
DATE_TIME	DATETIME
EMAIL	VARCHAR(255)
URL	VARCHAR(2048)
PHONE	VARCHAR(20)
CURRENCY	DECIMAL(18, 2)
PERCENT	DECIMAL(5, 2)
PICKLIST, MULTI_PICKLIST	VARCHAR(255)
LOOKUP, BELONGS_TO	VARCHAR(36)	References foreign record ID

Usage Flow

Creating a New Object

1. User creates object definition:

   POST /api/objects
   {
     "apiName": "Account",
     "label": "Account",
     "description": "Customer account records"
   }
   

2. ObjectService.createObjectDefinition() executes:

   • Inserts object metadata into object_definitions table
   • Generates create table SQL
   • Creates migration record with status "pending"
   • Executes migration immediately
   • Updates migration status to "executed"
   • Returns object definition

3. Result:

   • Object is now ready to use
   • Table exists in database
   • Migration history is recorded for future replication

Migration Execution Flow

createAndExecuteMigration()
├── createMigrationRecord()
│   └── Insert into custom_migrations (status: pending)
└── executeMigration()
    ├── Fetch migration record
    ├── Execute SQL
    ├── Update status: executed
    └── Return migration record

Error Handling

Migrations track execution status and errors:

• Status: pending - Not yet executed
• Status: executed - Successfully completed
• Status: failed - Error during execution

Failed migrations are logged and stored with error details for debugging and retry:

{
  id: "uuid",
  status: "failed",
  error: "Syntax error in SQL...",
  executedAt: null,
  updated_at: "2025-12-24T11:00:00Z"
}

Future Functionality

Sandbox Environment Replication

Stored migrations enable:

1. Cloning production environments - Replay all migrations in new database
2. Data structure export/import - Export migrations as SQL files
3. Audit trail - Complete history of schema changes
4. Rollback capability - Add down migrations for reverting changes
5. Dependency tracking - Identify object dependencies from migrations

Planned Enhancements

1. Add down migrations - Support undoing schema changes
2. Migration dependencies - Track which migrations depend on others
3. Batch execution - Run pending migrations together
4. Version control - Track migration versions and changes
5. Manual migration creation - API to create custom migrations
6. Migration status dashboard - UI to view migration history

Integration Points

ObjectService

• Uses getTenantKnexById() for tenant database connections
• Calls CustomMigrationService after creating object definitions
• Handles migration execution errors gracefully (logs but doesn't fail)

TenantDatabaseService

• Provides database connections via getTenantKnexById()
• Connections are cached with prefix id:${tenantId}

Module Dependencies

ObjectModule
├── imports: [TenantModule, MigrationModule]
└── providers: [ObjectService, CustomMigrationService, ...]

MigrationModule
├── imports: [TenantModule]
└── providers: [CustomMigrationService]

API Endpoints (Future)

While not yet exposed via API, these operations could be added:

// Get migration history
GET /api/migrations?tenantId=xxx&status=executed

// Get migration details
GET /api/migrations/:id

// Retry failed migration
POST /api/migrations/:id/retry

// Export migrations as SQL
GET /api/migrations/export?tenantId=xxx

// Create custom migration
POST /api/migrations
{
  name: "add_field_to_accounts",
  description: "Add phone_number field",
  sql: "ALTER TABLE accounts ADD phone_number VARCHAR(20)"
}

Testing

Manual Testing Steps

1. Create a new object:

   curl -X POST http://localhost:3000/api/objects \
     -H "Authorization: Bearer <token>" \
     -H "Content-Type: application/json" \
     -d '{
       "apiName": "TestObject",
       "label": "Test Object",
       "description": "Test object creation"
     }'
   

2. Verify table was created:

   # In tenant database
   SHOW TABLES LIKE 'test_objects';
   DESCRIBE test_objects;
   

3. Check migration record:

   # In tenant database
   SELECT * FROM custom_migrations WHERE name LIKE '%test_objects%';
   

4. Create a record in the new object:

   curl -X POST http://localhost:3000/api/test-objects \
     -H "Authorization: Bearer <token>" \
     -H "Content-Type: application/json" \
     -d '{
       "name": "My Test Record"
     }'
   

Troubleshooting

Migration Fails with SQL Error

1. Check custom_migrations table for error details:

   SELECT id, name, error, status FROM custom_migrations 
   WHERE status = 'failed';
   

2. Review the generated SQL in the sql column

3. Common issues:

   • Duplicate table names
   • Invalid field names (reserved SQL keywords)
   • Unsupported field types

Table Not Created

1. Verify custom_migrations table exists:

   SHOW TABLES LIKE 'custom_migrations';
   

2. Check object service logs for migration execution errors

3. Manually retry migration:

   const migration = await tenantKnex('custom_migrations')
     .where({ status: 'failed' })
     .first();
   await customMigrationService.executeMigration(tenantKnex, migration.id);
   

Performance Considerations

• Table creation is synchronous and happens immediately
• Migrations are cached in custom_migrations table per tenant
• No file I/O - all operations use database
• Index creation optimized with proper indexes on common columns (tenantId, status, created_at)

Security

• Per-tenant isolation - Each tenant's migrations stored separately
• No SQL injection - Using Knex query builder for all operations
• Access control - Migrations only created/executed by backend service
• Audit trail - Complete history of all schema changes

Related Files

• backend/src/object/object.service.ts
• backend/src/migration/custom-migration.service.ts
• backend/src/migration/migration.module.ts