我有一个以下格式的数据库结构,
科目表
章节目录表
教程表格
“subject_id应该在教程表中吗?”
科目表
subject_id subject_name
1 HTML
2 Java
章节目录表
chapter_id chapter_name subject_id
1 Doctype 1
2 Intro to Java 2
教程表格
tutorial_id tutorial_name chapter_id subject_id
1 Intro to doctype 1 1
2 Details of doctype 1 1
3 Intro to JVM 2 2
“subject_id应该在教程表中吗?”