What is the key difference between static SQL and dynamic SQL?

The key difference that makes the answer correct lies in how each type of SQL is processed and executed.

Static SQL is defined and compiled at the time of program creation. This means that the SQL statements are hard-coded into the application or program. As a result, the database system can optimize these queries at compile-time, ensuring that they run with greater efficiency and reliability. This also allows for compile-time error checking, which helps ensure that the SQL statements are correct before the program is ever run.

In contrast, dynamic SQL is constructed and executed at runtime. This means that the SQL statements can be generated on the fly, often based on user inputs or other dynamic conditions. While this provides great flexibility, it also means that the statements can only be checked and optimized at execution time. As a result, dynamic SQL can introduce additional overhead in resource usage, potential runtime errors, and debugging challenges due to the varying nature of queries.

Understanding this distinction is essential for database design and application development, as it influences performance, resource management, and maintainability of database applications.