Summary
In most cases, the decision about whether to use a relational or nonrelational database has already been made for you. If you’re migrating a database-backed application from your data center to AWS, chances are the application is already using a SQL database. In that case, your migration options are to either use RDS or build and maintain your own SQL server on one or more EC2 instances.
When it comes to developing a new database-backed application, whether to use a relational or nonrelational database is not an easy decision, nor is it always a clear-cut one. Both have their unique advantages and disadvantages, as shown in Table 9.3.
TABLE 9.3 Comparison of Relational and Nonrelational Databases
| Relational | Nonrelational |
| Designed for complex or arbitrary queries | Designed for a few well-defined queries |
| Requires structured data | Can store structured or unstructured data |
| Ideal for reporting and analysis | Ideal for highly transactional applications |
Note that...
