MongoDB Data Model: Why Is It More Flexible Than Relational Databases?

The article compares the data model differences between relational and MongoDB databases, with flexibility being the core distinction. Relational databases (e.g., MySQL) are centered on fixed tables with predefined columns, requiring table structure modifications (e.g., ALTER TABLE) for new fields, which is unfriendly to scenarios with rapidly changing requirements. MongoDB adopts a document - oriented model, where data is stored in JSON - like documents with no need for uniform fields. Different documents can contain different fields, and new fields can be added directly without structural changes. Its advantages include: flexible field structure (no predefined requirements), support for nested structures (reducing multi - table associations), adaptation to agile development (rapid response to requirements), and storage of sparse data (saving space). MongoDB is suitable for scenarios with rapid iteration, complex nested data, or non - uniform structures (such as the Internet of Things and log data), but it needs reasonable design to avoid performance issues caused by excessive nesting.