Пересматриваем решение на счёт SQL

src/model/book.h

@@ -0,0 +1,65 @@
+#ifndef BOOK_H
+#define BOOK_H
+
+#include <model/author.h>
+
+#include <sql_builder/create_table.h>
+
+#include <QString>
+
+namespace model
+{
+
+namespace bookconst
+{
+
+const QString TABLE = "books";
+
+const QString ID = "id";
+const QString TITLE = "title";
+const QString AUTHOR_ID = "author_id";
+const QString FILEPATH = "file_path";
+
+}
+
+struct Book
+{
+    int id = 0;
+    QString title;
+    Author author;
+    QString filePath;
+};
+
+static inline QString createTableBook()
+{
+    // query.exec("CREATE TABLE IF NOT EXISTS books ("
+    //            "id INTEGER PRIMARY KEY AUTOINCREMENT,"
+    //            "title TEXT NOT NULL,"
+    //            "file_path TEXT NOT NULL,"
+    //            "author_id INTEGER NOT NULL,"
+    //            "FOREIGN KEY (author_id) REFERENCES authors(id) ON DELETE CASCADE"
+    //            ");");
+
+    Builder::TableSchema tBuilder(model::bookconst::TABLE);
+    tBuilder.addColumn({ .name = model::bookconst::ID,
+                         .type = "INTEGER",
+                         .primaryKey = true });
+
+    tBuilder.addColumn({ .name = model::bookconst::TITLE,
+                         .type = "TEXT",
+                         .notNull = true });
+
+    tBuilder.addColumn({ .name = model::bookconst::FILEPATH,
+                         .type = "TEXT",
+                         .notNull = true });
+
+    tBuilder.addColumn({ .name = model::bookconst::AUTHOR_ID,
+                         .type = "INTEGER",
+                         .notNull = true,
+                         .foreignKeyTable = model::authorconst::TABLE,
+                         .foreignKeyColumn = model::authorconst::ID });
+    return tBuilder.get();
+}
+
+} // namespace model
+#endif // BOOK_H