Introduce MaybeError type

src/data_provider/sqlite.rs

@@ -5,19 +5,19 @@ pub fn create_db() {
     let db_file = db_path();
     if !db_file.exists() {
         std::fs::File::create(&db_file).expect("Database file creation failed");
-        let connection = Connection::open(&db_file).unwrap();
-        connection.execute("PRAGMA foreign_keys = ON;", []).unwrap();
+        let connection = Connection::open(&db_file).expect("Connection open failed");
+        connection.execute("PRAGMA foreign_keys = ON;", []).expect("Failed to set PRAGMA");
 
         create_tables(&connection);
     }
 }
 
 fn create_tables(conn: &Connection) {
-    make_card_set(conn).unwrap();
-    make_settings(conn).unwrap();
-    make_word_group(conn).unwrap();
-    make_words(conn).unwrap();
-    make_card_stats(conn).unwrap();
+    make_card_set(conn).expect("Failed to init table");
+    make_settings(conn).expect("Failed to init table");
+    make_word_group(conn).expect("Failed to init table");
+    make_words(conn).expect("Failed to init table");
+    make_card_stats(conn).expect("Failed to init table");
 }
 
 fn make_settings(conn: &Connection) -> Result<(), rusqlite::Error> {
@@ -51,7 +51,7 @@ fn make_card_stats(conn: &Connection) -> Result<(), rusqlite::Error> {
 
 pub fn default_connection() -> Connection {
     let db_file = db_path();
-    let connection = Connection::open(db_file).unwrap();
-    connection.execute("PRAGMA foreign_keys = ON;", []).unwrap();
+    let connection = Connection::open(db_file).expect("Failed to open database");
+    connection.execute("PRAGMA foreign_keys = ON;", []).expect("Failed to set PRAGMA");
     connection
 }