Salesforce migration deep dive

Salesforce Migration Deep Dive

Overview

Comprehensive guide for migrating data to/from Salesforce: ETL patterns using Bulk API 2.0, data mapping between CRM schemas, record relationship preservation, and validation.

Prerequisites

• Source and target Salesforce orgs (or external CRM)
• jsforce with Bulk API 2.0 access
• Understanding of sObject relationships and External IDs
• Staging sandbox for dry runs

Migration Types

Type	Complexity	Duration	Tool
CSV import (< 50K records)	Low	Hours	Data Import Wizard / Bulk API
CRM-to-Salesforce	Medium	Weeks	Custom ETL with jsforce
Org-to-org migration	Medium	Weeks	SFDX + Bulk API
Full re-platform	High	Months	Custom ETL + change management

Instructions

Step 1: Data Assessment

const conn = await getConnection();

// Count records per object
const objectCounts = await Promise.all(
  ['Account', 'Contact', 'Lead', 'Opportunity', 'Case'].map(async (obj) => {
    const result = await conn.query(`SELECT COUNT(Id) total FROM ${obj}`);
    return { object: obj, count: result.records[0].total };
  })
);

console.table(objectCounts);
// Account:      15,234
// Contact:      45,678
// Lead:         23,456
// Opportunity:  8,901
// Case:         67,890

// Check data storage limits
const limits = await conn.request('/services/data/v59.0/limits/');
console.log(`Data storage: ${limits.DataStorageMB.Max - limits.DataStorageMB.Remaining}/${limits.DataStorageMB.Max} MB`);

Step 2: Schema Mapping

// Map source fields to Salesforce sObject fields
interface FieldMapping {
  source: string;
  target: string;
  transform?: (value: any) => any;
  required: boolean;
}

const accountMappings: FieldMapping[] = [
  { source: 'company_name', target: 'Name', required: true },
  { source: 'industry_code', target: 'Industry', required: false,
    transform: (code) => INDUSTRY_MAP[code] || 'Other' },
  { source: 'annual_rev', target: 'AnnualRevenue', required: false,
    transform: (v) => typeof v === 'string' ? parseFloat(v.replace(/[$,]/g, '')) : v },
  { source: 'website_url', target: 'Website', required: false },
  { source: 'employee_count', target: 'NumberOfEmployees', required: false },
  { source: 'external_id', target: 'External_ID__c', required: true },
];

function transformRecord(
  source: Record<string, any>,
  mappings: FieldMapping[]
): Record<string, any> {
  const target: Record<string, any> = {};
  for (const mapping of mappings) {
    let value = source[mapping.source];
    if (value === undefined || value === null) {
      if (mapping.required) throw new Error(`Missing required field: ${mapping.source}`);
      continue;
    }
    if (mapping.transform) value = mapping.transform(value);
    target[mapping.target] = value;
  }
  return target;
}

Step 3: Migration Order (Respecting Relationships)

Migration order matters! Parent objects must be loaded before children.

1. Account          (no dependencies)
2. Contact          (depends on Account via AccountId)
3. Opportunity      (depends on Account via AccountId)
4. OpportunityContactRole (depends on Opportunity + Contact)
5. Case             (depends on Account + Contact)
6. Task / Event     (depends on Contact via WhoId, Account via WhatId)

Use External IDs to resolve relationships without knowing Salesforce IDs:
- Create External_ID__c on Account, Contact, Opportunity
- Use external ID references in child records

Step 4: Bulk Migration with External ID Relationships

import { getConnection } from './salesforce/connection';
import fs from 'fs';

const conn = await getConnection();

// Step 4a: Load Accounts first
const accountCsv = `Name,Industry,External_ID__c
Acme Corp,Technology,EXT-ACME-001
Globex Inc,Manufacturing,EXT-GLOBEX-002
Initech LLC,Consulting,EXT-INITECH-003`;

const accountResults = await conn.bulk2.loadAndWaitForResults({
  object: 'Account',
  operation: 'upsert',
  externalIdFieldName: 'External_ID__c',
  input: accountCsv,
});
console.log(`Accounts: ${accountResults.successfulResults.length} success, ${accountResults.failedResults.length} failed`);

// Step 4b: Load Contacts with Account relationship via External ID
const contactCsv = `FirstName,LastName,Email,Account.External_ID__c,External_ID__c
Jane,Smith,[email protected],EXT-ACME-001,EXT-CONTACT-001
John,Doe,[email protected],EXT-GLOBEX-002,EXT-CONTACT-002`;

const contactResults = await conn.bulk2.loadAndWaitForResults({
  object: 'Contact',
  operation: 'upsert',
  externalIdFieldName: 'External_ID__c',
  input: contactCsv,
});
// Account.External_ID__c resolves to the correct AccountId automatically!

Step 5: Validation

async function validateMigration(
  sourceCount: number,
  objectType: string
): Promise<{ passed: boolean; details: string }> {
  const conn = await getConnection();

  // Count migrated records
  const result = await conn.query(
    `SELECT COUNT(Id) total FROM ${objectType} WHERE External_ID__c != null`
  );
  const targetCount = result.records[0].total;

  // Check for orphaned relationships
  let orphans = 0;
  if (objectType === 'Contact') {
    const orphanResult = await conn.query(
      `SELECT COUNT(Id) total FROM Contact WHERE AccountId = null AND External_ID__c != null`
    );
    orphans = orphanResult.records[0].total;
  }

  const passed = targetCount === sourceCount && orphans === 0;
  return {
    passed,
    details: `Source: ${sourceCount}, Target: ${targetCount}, Orphans: ${orphans}`,
  };
}

Step 6: Rollback Plan

// Delete migrated records using External ID marker
async function rollbackMigration(objectType: string): Promise<void> {
  const conn = await getConnection();

  // Query all migrated records (identified by External_ID__c)
  const records = await conn.query(
    `SELECT Id FROM ${objectType} WHERE External_ID__c != null`
  );

  // Delete in reverse order (children first)
  const ids = records.records.map((r: any) => r.Id);
  for (let i = 0; i < ids.length; i += 200) {
    const batch = ids.slice(i, i + 200);
    await conn.sobject(objectType).destroy(batch);
  }

  console.log(`Rolled back ${ids.length} ${objectType} records`);
}

Output

• Data assessment with record counts and storage usage
• Field mapping layer transforming source to Salesforce schema
• Bulk API migration respecting parent-child relationships
• External ID-based relationship resolution (no hardcoded IDs)
• Validation and rollback procedures

Error Handling

Error	Cause	Solution
DUPLICATE_VALUE on External_ID__c	Re-running migration	Use upsert instead of insert
INVALID_CROSS_REFERENCE_KEY	Parent record not found	Verify parent loaded first, check External ID values
STORAGE_LIMIT_EXCEEDED	Org storage full	Delete test data or upgrade storage
Bulk job timeout	Very large dataset	Split into smaller jobs (< 100M records)
Field mapping errors	Source schema mismatch	Validate transform functions with sample data first

Resources

• Bulk API 2.0
• External ID Fields
• Data Import Best Practices
• Salesforce Data Loader

Next Steps

For advanced troubleshooting, see salesforce-advanced-troubleshooting.