Clone TODOs example for SQLite

Differences to Postgres version:
- Minor changes to schema
- Add TODO: "RETURNING" isn't supported, so retrieve ID separately

Cargo.lock

@@ -1765,6 +1765,18 @@ dependencies = [
  "structopt",
 ]
 
+[[package]]
+name = "sqlx-example-sqlite-todos"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "async-std",
+ "futures 0.3.4",
+ "paw",
+ "sqlx",
+ "structopt",
+]
+
 [[package]]
 name = "sqlx-macros"
 version = "0.3.2"

Cargo.toml

@@ -7,6 +7,7 @@ members = [
     "examples/postgres/listen",
     "examples/postgres/realworld",
     "examples/postgres/todos",
+    "examples/sqlite/todos",
 ]
 
 [package]

examples/sqlite/todos/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "sqlx-example-sqlite-todos"
+version = "0.1.0"
+edition = "2018"
+workspace = "../../../"
+
+[dependencies]
+anyhow = "1.0"
+async-std = { version = "1.5.0", features = [ "attributes" ] }
+futures = "0.3"
+paw = "1.0"
+sqlx = { path = "../../../", features = ["sqlite"] }
+structopt = { version = "0.3", features = ["paw"] }

examples/sqlite/todos/README.md

@@ -0,0 +1,27 @@
+# TODOs Example
+
+## Usage
+
+Declare the database URL:
+
+```
+export DATABASE_URL="sqlite:///path/to/this/directory/todos.db"
+```
+
+Create the database:
+
+```
+sqlite3 todos.db
+```
+
+Load the database schema (using the SQLite CLI interface opened from the previous command):
+
+```
+sqlite> .read schema.sql
+```
+
+Use `.exit` to leave the SQLite CLI. Then, to run this example:
+
+- Add a todo: `cargo run -- add "todo description"`
+- Complete a todo: `cargo run -- done <todo id>`
+- List all todos: `cargo run`

examples/sqlite/todos/schema.sql

@@ -0,0 +1,5 @@
+CREATE TABLE IF NOT EXISTS todos (
+    id          INTEGER PRIMARY KEY NOT NULL,
+    description TEXT NOT NULL,
+    done        BOOLEAN NOT NULL DEFAULT 0
+);

examples/sqlite/todos/src/main.rs

@@ -0,0 +1,103 @@
+use sqlx::SqlitePool;
+use sqlx::sqlite::SqliteQueryAs;
+use std::env;
+use structopt::StructOpt;
+
+#[derive(StructOpt)]
+struct Args {
+    #[structopt(subcommand)]
+    cmd: Option<Command>,
+}
+
+#[derive(StructOpt)]
+enum Command {
+    Add { description: String },
+    Done { id: i64 },
+}
+
+#[async_std::main]
+#[paw::main]
+async fn main(args: Args) -> anyhow::Result<()> {
+    let pool = SqlitePool::new(&env::var("DATABASE_URL")?).await?;
+
+    match args.cmd {
+        Some(Command::Add { description }) => {
+            println!("Adding new todo with description '{}'", &description);
+            let todo_id = add_todo(&pool, description).await?;
+            println!("Added new todo with id {}", todo_id);
+        }
+        Some(Command::Done { id }) => {
+            println!("Marking todo {} as done", id);
+            if complete_todo(&pool, id).await? {
+                println!("Todo {} is marked as done", id);
+            } else {
+                println!("Invalid id {}", id);
+            }
+        }
+        None => {
+            println!("Printing list of all todos");
+            list_todos(&pool).await?;
+        }
+    }
+
+    Ok(())
+}
+
+async fn add_todo(pool: &SqlitePool, description: String) -> anyhow::Result<i64> {
+    // Insert the TODO, then obtain the ID of this row
+    sqlx::query!(
+        r#"
+INSERT INTO todos ( description )
+VALUES ( $1 )
+        "#,
+        description
+    )
+    .execute(pool)
+    .await?;
+
+    let rec: (i64,) = sqlx::query_as(
+        "SELECT last_insert_rowid()"
+    )
+    .fetch_one(pool)
+    .await?;
+
+    Ok(rec.0)
+}
+
+async fn complete_todo(pool: &SqlitePool, id: i64) -> anyhow::Result<bool> {
+    let rows_affected = sqlx::query!(
+        r#"
+UPDATE todos
+SET done = TRUE
+WHERE id = $1
+        "#,
+        id
+    )
+    .execute(pool)
+    .await?;
+
+    Ok(rows_affected > 0)
+}
+
+async fn list_todos(pool: &SqlitePool) -> anyhow::Result<()> {
+    let recs = sqlx::query!(
+        r#"
+SELECT id, description, done
+FROM todos
+ORDER BY id
+        "#
+    )
+    .fetch_all(pool)
+    .await?;
+
+    for rec in recs {
+        println!(
+            "- [{}] {}: {}",
+            if rec.done { "x" } else { " " },
+            rec.id,
+            &rec.description,
+        );
+    }
+
+    Ok(())
+}