我试图在Entity Framework中创建我认为可选的1：1或可能0..1：0..1关系。我希望能够在两个对象上都有导航属性。
我在现有数据库架构上使用Entity Framework的Fluent API。
为简单起见，我们假设以下表格：
Car
Id int not null
Driver
Id int not null
CarId int null unique
使用以下类：
public class Car
{
public int Id { get; set; }
public virtual Driver { get; set; }
}
public class Driver
{
public int Id { get; set; }
public virtual Car { get; set; }
}
这个想法是汽车和驾驶员可以彼此独立存在，但是当驾驶员与汽车相关联时，它是一个互斥的关联：驾驶员只能与该汽车相关联且该汽车只能关联那个司机。
我尝试了以下流畅的配置：
内部驱动程序的配置：
HasOptional(d => d.Car)
.WithOptionalDependent()
.Map(d => d.MapKey("CarId"));
在汽车配置中
HasOptional(c => cDriver)
.WithOptionalPrincipal()
.Map(d => d.MapKey("CarId"));
当我尝试这个时，我得到以下内容：
指定的架构无效。错误： （203,6）：错误0019：类型中的每个属性名称必须是唯一的。物业名称＆＃39; CarId＆＃39;已经定义了。
有没有办法使用Entity Framework中两个对象的导航属性为此场景建模？
答案 0 :(得分：0)
您可以在没有Fluent API的情况下执行此操作：
CEQ_DA = @(w) fzero(@(CEQ) fp(CEQ, w),CEQ_DA_0);
然后你需要检查司机是否已经有车，以保证他只能有一辆车。
答案 1 :(得分：0)
您不需要在两个流利的课程中进行设置。我很惊讶这是你收到的错误，而不是已经建立了这种关系。
您的云端硬盘类需要CarId作为课程的一部分：
public class DialogLoginWelcome extends Dialog implements OnClickListener, IUserLoginListener, TimelineListener{
TextView join, forgot;
EditText email, password;
Button login;
LoginButton facebook;
Boolean state;
String fbEmail, fbPass;
Calendar cal;
Session session;
IUserLoginListener mIUserLoginListener;
UserLoginHelper mUserLoginHelper;
Context context;
public DialogLoginWelcome(Context context) {
super(context);
this.context = context;
}
public DialogLoginWelcome(Context context, int theme) {
super(context, theme);
this.context = context;
}
public DialogLoginWelcome(Context context, boolean cancelable, OnCancelListener cancelListener) {
super(context, cancelable, cancelListener);
this.context = context;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
setContentView(R.layout.login_welcome_back);
getWindow().setLayout(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
mIUserLoginListener = this;
}
public void init(DialogLoginWelcome dialog){
join = (TextView) dialog.findViewById(R.id.welcome_join_now_textView3);
forgot = (TextView) dialog.findViewById(R.id.welcome_forgot_textView4);
email = (EditText) dialog.findViewById(R.id.welcome_email_editText1);
password = (EditText) dialog.findViewById(R.id.welcome_password_editText2);
facebook = (LoginButton) dialog.findViewById(R.id.welcome_fb_connect_button1);
login = (Button) dialog.findViewById(R.id.welcome_login_button2);
facebook.setReadPermissions(Arrays.asList("email","public_profile"));
facebook.setSessionStatusCallback(statusCallback);
facebook.setUserInfoChangedCallback(new LoginButton.UserInfoChangedCallback() {
@Override
public void onUserInfoFetched(GraphUser user) {
session = Session.getActiveSession();
Log.d("ohad", "facebook login changed! --- ");
if(user != null){
ProgressBarClass.startLoading(context);
Log.d("ohad", user.toString());
cal = Calendar.getInstance();
mUserLoginHelper = new UserLoginHelper(mIUserLoginListener);
mUserLoginHelper.postUserDetails(user.getProperty("email").toString().trim(), user.getId().trim());
}
}
});
join.setOnClickListener(this);
forgot.setOnClickListener(this);
login.setOnClickListener(this);
//email.setText("test@infibond.com");
//password.setText("a");
//email.setText("naamaraviv@walla.co.il"); //Production
//password.setText("naama1978raviv");
//email.setText("kraus@infibond.com"); //Dev
//password.setText("kraus246");
//email.setText("ohadshiffer28@walla.co.il"); //Production
//password.setText("1234");
email.setText("noam@infibond.com"); //Production & Dev
password.setText("nl555");
//email.setText("max@wsiseo.co.il"); //Production
//password.setText("wsi768");
}
@Override
public void onClick(View v) {
switch(v.getId()){
case R.id.welcome_join_now_textView3: //JOIN
dismiss();
DialogLoginSignup dialog = new DialogLoginSignup(context, R.style.DialogTheme);
dialog.show();
dialog.init(dialog);
break;
case R.id.welcome_forgot_textView4: //FORGOT
//context.startActivity(new Intent(context, ForgotPassActivity.class));
break;
case R.id.welcome_fb_connect_button1: //FACEBOOK
break;
case R.id.welcome_login_button2: //LOGIN
//VALIDATION OF INPUT SCREEN
//IF FIELDS ARE EMPTY - SHOW ALERT MESSAGE.
if (email.getText().toString().equals("")|| password.getText().toString().equals("")){
Alert_Dialog.showAler(context, "Enter the required fields.", "Error!");
}
else { //IF FIELDS AREN'T EMPTY
state = Utility.isOnline(context);
if (state == true) {
ProgressBarClass.startLoading(context);
new UserLoginHelper(this).postUserDetails(email
.getText().toString().trim(), password
.getText().toString().trim());
} else if (state == false) {
Alert_Dialog.showAler(context, "Check Internet Connection", "Network Error!");
}
}
break;
}
}
@Override
public void onUserLoginError(String errorMsg) {
ProgressBarClass.dismissLoading();
Alert_Dialog.showAler(context, errorMsg, "Error");
}
@Override
public void onUserLoginSuccess(String response) {
JSONObject res;
try {
res = new JSONObject(response);
Constant.me.setName(res.getString("full_name"));
Constant.me.setEmail(res.getString("email"));
Constant.me.setFirstName(res.getString("first_name"));
Constant.me.setLastName(res.getString("last_name"));
Constant.me.setBirth_date(res.getString("birthday"));
Constant.me.setBody_value(res.getString("bio"));
Constant.me.setProfileImageUrl(res.getString("picture"));
Constant.me.setPrivacy(res.getString("privacy"));
Constant.me.setPermissions(res.getString("permissions"));
Constant.me.setUid(res.getString("uid"));
Constant.me.setRelationship("self");
} catch (JSONException e) {
e.printStackTrace();
} finally{
new TimeHelper(this).getAlbumDetails(Constant.INFIBOND_DEV_SERVER_URL +
"timeline/get?uid=" + Constant.me.getUid() +
"&userType=user" +
"&storiesLimitPerYear=6");
}
}
@Override
public void onTimelineError(String errorMsg) {
ProgressBarClass.dismissLoading();
Alert_Dialog.showAler(context, errorMsg, "Error");
}
@Override
public void onTimelineSuccess(String response) {
JSONObject res = null;
try {
res = new JSONObject(response);
} catch (JSONException e) {
e.printStackTrace();
}
Intent intent = new Intent(context, MyInfiActivity.class);
intent.putExtra("moments", res.toString());
context.startActivity(intent);
ProgressBarClass.dismissLoading();
((Activity) context).finish();
}
private Session.StatusCallback statusCallback = new Session.StatusCallback() {
@Override
public void call(Session session, SessionState state, Exception exception) {
if (state.isOpened()) {
Log.d("ohad", "Facebook session opened. 3");
} else if (state.isClosed()) {
Log.d("ohad", "Facebook session closed. 3");
}
}
};
}
然后你只需在驱动程序的Fluent Config文件中使用它，而在Car的一个文件中没有任何内容。
public class Driver
{
public int Id { get; set; }
// Make this int? if a Driver can exist without a Car
public int CarId { get; set; }
public virtual Car { get; set; }
}