Rust Static and Dynamic Dispatch

Tue, 05 May 2026 12:00:00 +0530

In Java, there are two broad use cases for type abstraction:

Compile-time polymorphism: A class or function works over different data types while preserving type safety. For example, ArrayList<User>, HashMap<String, Double>, Optional<User>. The compiler ensures that there is no type mismatch and prevents a variable of type ArrayList<User> from being assigned an ArrayList<String>.
Runtime polymorphism: The code uses the advertised capabilities of an interface but does not determine the concrete implementation. For example, a method accepts List<User> but the caller can pass ArrayList<User> or LinkedList<User>.

Understanding Rust Associated Types

Sun, 15 Mar 2026 12:00:00 +0530

pgqrs supports multiple databases including PostgreSQL and SQLite.

An application uses pgqrs with a specific database that is chosen as a feature.

[dependencies]
# PostgreSQL only (default)
pgqrs = "0.15.2"

# SQLite only
pgqrs = { version = "0.15.1", default-features = false, features = ["sqlite"] }

The choice of database determines:

dialect
client library
specific functions such as handling timestamps.

The important detail is that these differences are not chosen per method call. Once the backend is selected, the dialect and timestamp handling are fixed.

Traits on vrajat

Rust Static and Dynamic Dispatch

Understanding Rust Associated Types