Tom Hollander, Rajesh Vinayagam, and Krishnakumar Sathyanarayana outline the complexities and strategies involved in migrating SQL databases to MongoDB, particularly emphasizing the importance of schema design to optimize performance and cost-effectiveness. MongoDB's flexibility in schema design requires careful consideration of data relationships and access patterns to avoid negative impacts on application performance. PeerIslands has developed a pre-migration analysis approach, which automates the evaluation of existing SQL footprints to provide insights for optimal schema design in MongoDB, addressing challenges like non-codified relational constraints and data access patterns. This approach, proven with large clients like a major US insurance provider, streamlines the migration process, providing recommendations that facilitate effective schema design and data migration. PeerIslands collaborates closely with MongoDB's Relational Migrator team to automate these analyses further, aiming to prevent incorrect schema designs and accelerate the migration process across various SQL databases.