我在ClassSelector DB兩個表:創建INNER_JOIN表或創建新表的MySQL
學生
student_id數據| student_name |家鄉
類
類標識碼| classname |描述
我正在嘗試編寫一個程序,該程序將接受用戶輸入的student_id並允許他們從類ID列表中選擇一個類。我希望應用程序將student_id,student_name,class_id,classname寫入單獨的表中。要做到這一點,那將是最好創建一個新的表(student_x_class),並使用INSERT語句:
INSERT INTO ClassSelector.student_x_class ClassSelector.students.student_id,ClassSelector.students.student_name, ClassSelector.classes.class_id,ClassSelector.classes.classname VALUES(W, X, Y, Z);
或創建的類表(student_x_class)新的一列,並以此作爲一個外鍵student_id列並使用內部連接。
對不起,如果這是混淆,我是MySQL的新手。任何幫助,將不勝感激!
ResultSet rs3 = myStmt3.executeQuery("SELECT * FROM ClassSelector.classes WHERE class_id = " + selectedClass);
while(rs3.next()){
String innerJoin = (userEnterId + " has been added to " + rs3.getString("classname") + " " + rs3.getString("class_id"));
System.out.println(innerJoin);
String student_classJoin = "INSERT INTO students_x_classes" + "(student_name, class_id, classname)" + "VALUES (?, ?, ?)";
PreparedStatement pStmt = con.prepareStatement(student_classJoin);
pStmt.setString(1, userEnterId);
pStmt.setString(2, rs2.getString("class_id"));
pStmt.setString(3, rs2.getString("classname"));
pStmt.executeUpdate();
input.close();
}
對不起,radoh,我改變了說INSERT INTO students to students_x_classes的地方。我想從students表和classes表中取出列並將它們插入到students_x_classes表中;我認爲我這樣做不正確。 – Rassisland