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我有一種情況，我有一個實體OrderedItem，它與另一個實體Order有多對一的關係。當我嘗試堅持的Order實體收到以下錯誤：無法堅持實體（單向多對一關係）
> The bean encountered a non-application exception; nested exception is:
> javax.persistence.PersistenceException: Exception [EclipseLink-4002]
> (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b):
> org.eclipse.persistence.exceptions.DatabaseException Internal
> Exception: com.sap.db.jdbc.exceptions.JDBCDriverException: SAP DBTech
> JDBC: [257]: sql syntax error: incorrect syntax near "ORDER": line 1
> col 13 (at pos 13) Error Code: 257 Call: INSERT INTO ORDER (ID,
> ORDEREDAT, STATUS, TABLE, acceptor_id, waiter_id) VALUES (?, ?, ?, ?,
> ?, ?) bind => [6 parameters bound] Query:
> InsertObjectQuery([Timestamp: 2013-07-16 19:17:56.708 Table: 365
> Status: NEW Waiter: [ID: 1 EGN: 9999999999 Name: Kukata Role: [Role:
> Manager]] Acceptor: [ID: 1 EGN: 9999999999 Name: Kukata Role: [Role:
> Manager]]])
這裏是我的Order實體
@Entity
public class Order implements Serializable {
private static final long serialVersionUID = 1L;
public static enum Status{
NEW,
PROCESSED
}
@Id
@GeneratedValue(strategy = GenerationType.TABLE)
private long id;
@NotNull
@Column(nullable = false)
private Timestamp orderedAt;
@NotNull
@Column(nullable = false)
private Integer table;
@NotNull
@ManyToOne(optional = false)
@JoinColumn(name = "waiter_id", referencedColumnName = "id")
private Employee waiter;
@NotNull
@Enumerated(EnumType.STRING)
private Status status;
@ManyToOne(optional = true)
@JoinColumn(name = "acceptor_id", referencedColumnName = "id")
private Employee acceptor;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public Timestamp getOrderedAt() {
return orderedAt;
}
public void setOrderedAt(Timestamp param) {
this.orderedAt = param;
}
public Integer getTable() {
return table;
}
public void setTable(Integer param) {
this.table = param;
}
public Employee getWaiter() {
return waiter;
}
public void setWaiter(Employee param) {
this.waiter = param;
}
public Status getStatus() {
return status;
}
public void setStatus(Status param) {
this.status = param;
}
public Employee getAcceptor() {
return acceptor;
}
public void setAcceptor(Employee param) {
this.acceptor = param;
}
@Override
public String toString() {
return new StringBuilder().append("[Timestamp: ").append(orderedAt)
.append("\tTable: ").append(table).append("\tStatus: ")
.append(status).append("\tWaiter: ").append(waiter)
.append("\tAcceptor: ").append(acceptor).append("]").toString();
}
}
這裏是我的orderedItem實體
@Entity
@Table(name = "OrderedItem")
public class OrderedItem implements Serializable {
private static final long serialVersionUID = 1L;
public OrderedItem() {
}
@Id
@GeneratedValue(strategy = GenerationType.TABLE)
private long id;
@NotNull
@Column(nullable = false)
private Integer quantity;
@NotNull
@Column(nullable = false)
private Double price;
@NotNull
@OneToOne(optional = false)
@JoinColumn(name = "item_id", referencedColumnName = "id")
private Item item;
@NotNull
@ManyToOne(optional = false)
@JoinColumn(name = "order_id", referencedColumnName = "id")
private Order order;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public Integer getQuantity() {
return quantity;
}
public void setQuantity(Integer param) {
this.quantity = param;
}
public Double getPrice() {
return price;
}
public void setPrice(Double param) {
this.price = param;
}
public Item getItem() {
return item;
}
public void setItem(Item param) {
this.item = param;
}
public Order getOrder() {
return order;
}
public void setOrder(Order param) {
this.order = param;
}
@Override
public String toString() {
return new StringBuilder().append("[Order: ").append(order)
.append("Item: ").append(item).append("\tQuantity: ")
.append(quantity).append("\tPrice: ").append(price).append("]")
.toString();
}
}
我的僱員實體
@Entity
@Table(name = "Employee")
public class Employee implements Serializable {
private static final long serialVersionUID = 1L;
public Employee() {
}
@Id
@GeneratedValue(strategy = GenerationType.TABLE)
private long id;
@NotNull
@Column(nullable = false)
private String name;
@NotNull
@Column(nullable = false, unique = true)
private String egn;
@NotNull
@Column(nullable = false)
private byte[] pwd;
@NotNull
@ManyToOne(optional = false)
@JoinColumn(name = "Role_role", referencedColumnName = "role")
private Role role;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String param) {
this.name = param;
}
public String getEGN() {
return egn;
}
public void setEGN(String param) {
this.egn = param;
}
public byte[] getPwd() {
return pwd;
}
public void setPwd(byte[] param) {
this.pwd = param;
}
public Role getRole() {
return role;
}
public void setRole(Role param) {
this.role = param;
}
@Override
public String toString() {
return new StringBuilder().append("[ID: ").append(id).append("\tEGN: ")
.append(egn).append("\tName: ").append(name).append("\tRole: ")
.append(role).append("]").toString();
}
}
一切工作正常，直到我試圖堅持訂單實體。這是一個虛擬的測試Servlet
import java.io.IOException;
import java.sql.Timestamp;
import java.util.List;
import javax.ejb.EJB;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.persistence.dao.CategoryDAO;
import org.persistence.dao.EmployeeDAO;
import org.persistence.dao.ItemDAO;
import org.persistence.dao.OrderDAO;
import org.persistence.dao.OrderedItemDAO;
import org.persistence.dao.RoleDAO;
import sbms.persistence.entities.Category;
import sbms.persistence.entities.Employee;
import sbms.persistence.entities.Item;
import sbms.persistence.entities.Order;
import sbms.persistence.entities.OrderedItem;
import sbms.persistence.entities.Role;
public class Test extends HttpServlet {
private static final long serialVersionUID = 1L;
@EJB
private CategoryDAO categoryDAO;
@EJB
private OrderDAO orderDAO;
@EJB
private OrderedItemDAO orderedItemDAO;
@EJB
private ItemDAO itemDAO;
@EJB
private RoleDAO roleDAO;
@EJB
private EmployeeDAO employeeDAO;
public Test() {
super();
// TODO Auto-generated constructor stub
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
try {
response.getWriter().print(
"<p>Checking if the Role 'Manager' exists.</p>");
Role managerRole = null;
List<Role> roles = roleDAO.getAll(
"select X from Role X where X.role = ?1",
Role.ERoles.Manager);
if (roles.size() == 0) {
response.getWriter().print(
"<p>The role 'manager' does not exist. Adding it.</p>");
Role role = new Role();
role.setRole(Role.ERoles.Manager);
roleDAO.add(role);
managerRole = role;
} else {
response.getWriter().print(
"<p>The role 'manager' does exists.</p>");
managerRole = roles.get(0);
}
response.getWriter().print(
"<p>Checking if there are any managers</p>");
List<Employee> employes = employeeDAO.getAll(
"select X from Employee X where X.role = ?1", managerRole);
if (employes.size() == 0) {
response.getWriter().print(
"<p>There are no managers. Adding new one.</p>");
Employee employee = new Employee();
employee.setEGN("9999999999");
employee.setName("Kukata");
employee.setPwd("password".getBytes());
employee.setRole(managerRole);
employeeDAO.add(employee);
}
response.getWriter().print("<p>Checking for category 'Vodka'</p>");
Category category = null;
List<Category> categories = categoryDAO.getAll(
"select X from Category X where X.name = ?1", "Vodka");
if (categories.size() == 0) {
category = new Category();
response.getWriter().print("<p>Adding category Vodka</p>");
category.setName("Vodka");
categoryDAO.add(category);
}else{
category = categories.get(0);
}
response.getWriter().print("<p>Checking for Russian Standard :D</p>");
Item item = null;
List<Item> items = itemDAO.getAll("select X from Item X where X.name = ?1", "RussianStandard");
if(items.size() == 0){
response.getWriter().print(
"<p>Adding item vodka Russian Standard</p>");
item = new Item();
item.setCategory(category);
item.setPrice(35.6);
item.setName("RussianStandard");
itemDAO.add(item);
}else{
item = items.get(0);
}
response.getWriter().print("<p>Making an order</p>");
// Get the employee who accepted the order (in this example -
// Kukata)
List<Employee> acceptor = employeeDAO.getAll(
"select X from Employee X where X.egn = ?1", "9999999999");
if (acceptor.size() == 0) {
response.getWriter().print(
"<p>Error -there is no such employee</p>");
return;
}
Order order = new Order();
order.setStatus(Order.Status.NEW);
order.setOrderedAt(new Timestamp(System.currentTimeMillis()));
order.setTable(365);
// Kuakata accepted and processed the order!
order.setWaiter(acceptor.get(0));
order.setAcceptor(acceptor.get(0));
response.getWriter().print("<p>Persisting the order</p>");
orderDAO.add(order);
response.getWriter().print("<p>Adding the ordered items</p>");
OrderedItem orderedItem = new OrderedItem();
// We set the previously created item(vodka), but we can also get it
// from the db
orderedItem.setItem(item);
orderedItem.setOrder(order);
orderedItem.setPrice(item.getPrice());
orderedItem.setQuantity(5);
orderedItemDAO.add(orderedItem);
response.getWriter().print("<p>Lets see what we have done:</p>");
} catch (Exception e) {
response.getWriter().print(e.getMessage());
}
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
}
'ORDER'是[hana]（http://help.sap.com/hana/html/_bsql_introduction.html）中的保留關鍵字。 –
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