我有两个实体,一个是DataBase,另一个ID是Digraph,这里是代码
package com.google.GPtest.server;
@PersistenceCapable(identityType = IdentityType.APPLICATION) 公共类DataBase实现Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Long pid;
// @Extension(vendorName="datanucleus", key="gae.encoded-pk", value="true")
@Persistent
private String id;
@Persistent
private User user;
@Persistent
private double press='\0';
@Persistent
private double release='\0';
/*@Persistent
private double time='\0';*/
@Persistent
private int index;
@Persistent
private String value;
@Persistent
private String location;
@Persistent
private Date createDate;
@Persistent(mappedBy="data")
private List<Digraph> sig=new ArrayList<Digraph>();
public DataBase(String id,User user, String value,double press,double release,int index,String location) {
this.user = user;
this.setValue(value);
this.setPress(press);
this.setRelease(release);
this.setIndex(index);
this.setLocation(location);
this.setId(id);
this.createDate = new Date();
}
public String getId() {
return this.id;
}
public void setId(String id){
this.id=id;
}
public User getUser() {
return this.user;
}
/*public String getSymbol() {
return this.symbol;
}*/
public Date getCreateDate() {
return this.createDate;
}
public void setUser(User user) {
this.user = user;
}
public void setValue(String value) {
this.value = value;
}
public String getValue() {
return value;
}
public void setIndex(int index) {
this.index = index;
}
public int getIndex() {
return index;
}
/*public void setTime(double time) {
this.time = time;
}
public double getTime() {
return time;
}*/
public void setRelease(double release) {
this.release = release;
}
public double getRelease() {
return release;
}
public void setPress(double press) {
this.press = press;
}
public double getPress() {
return press;
}
public void setLocation(String location) {
this.location = location;
}
public String getLocation() {
return location;
}
public void setSig(List<Digraph> sig) {
this.sig = sig;
}
public List<Digraph> getSig() {
return sig;
}
/*public void setSymbol(String symbol) {
this.symbol = symbol;
}*/
}
@PersistenceCapable(identityType = IdentityType.APPLICATION) 公共类Digraph实现Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
@Persistent
private String name;
@Persistent
private DataBase data;
public Digraph(String name){
this.name=name;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setData(DataBase data) {
this.data = data;
}
public DataBase getData() {
return data;
}
很明显,Digraph实体是DataBase的孩子......实际上我想在那个关系中建立一个连接,是否有人有想法?