Move database to backend module

src/backend/database/mod.rs

@@ -0,0 +1,59 @@
+use anyhow::Result;
+use diesel::prelude::*;
+
+pub mod ensembles;
+pub use ensembles::*;
+
+pub mod instruments;
+pub use instruments::*;
+
+pub mod medium;
+pub use medium::*;
+
+pub mod persons;
+pub use persons::*;
+
+pub mod recordings;
+pub use recordings::*;
+
+pub mod thread;
+pub use thread::*;
+
+pub mod works;
+pub use works::*;
+
+mod schema;
+
+// This makes the SQL migration scripts accessible from the code.
+embed_migrations!();
+
+/// Generate a random string suitable as an item ID.
+pub fn generate_id() -> String {
+    let mut buffer = uuid::Uuid::encode_buffer();
+    let id = uuid::Uuid::new_v4().to_simple().encode_lower(&mut buffer);
+
+    id.to_string()
+}
+
+/// Interface to a Musicus database.
+pub struct Database {
+    connection: SqliteConnection,
+}
+
+impl Database {
+    /// Create a new database interface and run migrations if necessary.
+    pub fn new(file_name: &str) -> Result<Database> {
+        let connection = SqliteConnection::establish(file_name)?;
+
+        diesel::sql_query("PRAGMA foreign_keys = ON").execute(&connection)?;
+        embedded_migrations::run(&connection)?;
+
+        Ok(Database { connection })
+    }
+
+    /// Defer all foreign keys for the next transaction.
+    fn defer_foreign_keys(&self) -> Result<()> {
+        diesel::sql_query("PRAGMA defer_foreign_keys = ON").execute(&self.connection)?;
+        Ok(())
+    }
+}