chore: add simple examples

Closes #3

Cargo.toml

@@ -33,3 +33,11 @@ all-features = true
 
 [workspace]
 members = ["examples/*"]
+
+[[example]]
+name = "simple"
+required-features = ["r2d2_postgres"]
+
+[[example]]
+name = "transaction"
+required-features = ["r2d2_postgres", "nightly"]

examples/README.md

@@ -0,0 +1,19 @@
+# Examples
+
+By default, all examples in this directory require a postgres server, which you can run using `docker-compose.dev.yml` in the `examples/web` directory.
+
+## Simple
+
+This example initializes persistence, gets a connection and runs the query.
+
+```sh
+cargo run --example simple --features r2d2_postgres
+```
+
+## Transaction
+
+This is extended simple example where we also upgrade existing connection to transaction and run query. Then we close transaction and use connection.
+
+```sh
+cargo run --example transaction --features "nightly r2d2_postgres"
+```

examples/simple.rs

@@ -0,0 +1,36 @@
+use ood_persistence::r2d2_postgres::{postgres, NoTlsManager};
+pub use ood_persistence::r2d2_postgres::{
+    NoTlsConnection as PostgresConnection, NoTlsPersistence as PostgresPersistence,
+    NoTlsPool as PostgresPool,
+};
+pub use ood_persistence::{
+    error::Result as QueryResult,
+    syn::{ConnectionClient, PersistencePool},
+};
+
+const DATABASE_URL: &str = "postgres://postgres:test@localhost:5577/x";
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // create pool to our database
+    let pool = create_postgres_pool();
+    // initialize persistence
+    let persistence = ood_persistence::r2d2_postgres::new(&pool);
+    // get connection to database
+    let mut conn = persistence.get_connection()?;
+    // we can query something
+    let res: i32 = conn.inner().query_one("select 1", &[])?.get(0);
+    assert_eq!(res, 1);
+
+    Ok(())
+}
+
+pub fn create_postgres_pool() -> PostgresPool {
+    let db_conn_config = DATABASE_URL
+        .parse()
+        .expect("Failed to convert database url to database config");
+
+    let manager = NoTlsManager::new(db_conn_config, postgres::NoTls);
+    PostgresPool::builder()
+        .build(manager)
+        .expect("Failed to create database pool")
+}

examples/transaction.rs

@@ -0,0 +1,49 @@
+use ood_persistence::r2d2_postgres::{postgres, NoTlsManager};
+pub use ood_persistence::r2d2_postgres::{
+    NoTlsConnection as PostgresConnection, NoTlsPersistence as PostgresPersistence,
+    NoTlsPool as PostgresPool,
+};
+pub use ood_persistence::{
+    error::Result as QueryResult,
+    syn::{ConnectionClient, PersistencePool, TransactionClient},
+};
+
+const DATABASE_URL: &str = "postgres://postgres:test@localhost:5577/x";
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // create pool to our database
+    let pool = create_postgres_pool();
+    // initialize persistence
+    let persistence = ood_persistence::r2d2_postgres::new(&pool);
+    // get connection to database
+    let mut conn = persistence.get_connection()?;
+    // we can query something
+    let res: i32 = conn.inner().query_one("select 1", &[])?.get(0);
+    assert_eq!(res, 1);
+
+    // and we can upgrade connection to transaction
+    let mut trx = conn.start_transaction()?;
+    // we can query or execute something in transaction
+    let res: i32 = trx.inner().query_one("select 2", &[])?.get(0);
+    assert_eq!(res, 2);
+    // now we close transaction
+    trx.rollback()?;
+    // or trx.commit()?;
+
+    // and we can use connection again as well
+    let res: i32 = conn.inner().query_one("select 3", &[])?.get(0);
+    assert_eq!(res, 3);
+
+    Ok(())
+}
+
+pub fn create_postgres_pool() -> PostgresPool {
+    let db_conn_config = DATABASE_URL
+        .parse()
+        .expect("Failed to convert database url to database config");
+
+    let manager = NoTlsManager::new(db_conn_config, postgres::NoTls);
+    PostgresPool::builder()
+        .build(manager)
+        .expect("Failed to create database pool")
+}