We are performing a data migration in salesforce application and i am going to validate the migrated data (including schema at field, table and database level). I planned to use REST API but SQL Server Integration Services tool is also advised in our organisation. I feel creating test library that consumes the REST API is more efficient as we can validate the schema and data and do the comparison through code. But i need expert's advice which one we can use and what can be the best approach. I cannot use any third party software due to license constraint.
The data in question here are being migrated from multiple salesforce orgs to one single org.