Asp.net mvc 5 Identity 2.0 will create 5 tables automatically when run the mvc project.
Here, my question is why some tables like AspnetUser, it's item 'Id' type defined to string.
The String seems like GUID, but why it doesn't define to guid type instead of using string.
Is it transfer data type from string or do something when quering data ?
I can't figure out why it define to string, but look like guid ?
another table have same problem like AspnetRole, it's item 'UserId', 'RoleId' defined to string too.
Have any idea ?
I'm guessing this is having different reasons.
One reason is the insert performance for Guids, which will get slower and slower after an amount of data (Clustered indexes).
Another reason is the difference of handling Guid in different databases. Microsoft Sql Server has an UniqueIdentifier type that is a Guid, MySql will store them as strings, Oracle stores the raw bytes of a Guid...
I hope this explains a part of your queustion, as not fully :)...
Identity framework not only created for code first approach to be generate database tables with given fields or datatypes. Identity framework can be used against existing database or migrate old asp.net membership provider, or we can use our own table names with extra database fields to store more data on identity tables.
Further more, the Id of the aspnetUser table (that is the User table) used as string because, we can use Guid, integer, long etc. for this field depending on the requirement.
E.g. : If you decided to use integer as Id of the aspnetUser table (User table), then the database field will be auto increment int (or bigInt or etc.) field. But you need to do model binding in order to fulfill entity framework migration requirements.
By default we get Guid inserted into this field when we use out of the box asp.net Identity framework.
When you have defined roles for the registered user, there will be record added into AspnetRole table, this is also completely depending on the fields we defined on the tables as I discussed before. If we decided to use integer as Id of the aspnetUser table, then AspnetRole table fields updated according to the relationship with aspnetUser table fields.
Hope this helps.
Related
I have an existing database and one of the tables for the existing webforms application is a join or bridge table called PostCategory that links up Posts and Categories but it uses GUIDs to do that. It has GUIDs for CategoryID and PostID. When I tried use fluent mapping to point EF at that table I got the error that only ints can be used.
So I suspect the answer is no but I wanted to ask in case someone has done it. According to this post, it is possible with NHibernate but not EF.
This is not possible with EF because it doesn't support unique keys. Only primary keys can be used as principal in relation.
Now the post is from 2012 so I though maybe something has changed with EF6.
First of all, I only want one database, not an extra silly little thing for credentials. I have read that this provider uses the UserProfiles table to store login credentials. I would like to use my Occupant table, and not have to link the two. Is this possible, and how do I do it?
If it must be UserProfile, could I perhaps inherit Occupant from that using EF inheritence features, so the provider sees only a UserProfile interface on my Occupant table?
You can change the name of the table to use in the WebSecurity.InitializeDatabaseConnection method. There is a parameter in this method called userTableName. If you have a different name for the user name column in the Occupant table then you would also specify that in the parameter userNameColumn. Also the identification column name used in your table would be specified in userIdColumn. There are techniques for including the SimpleMembership database with your your own database and the details depend upon if you are using the code-first or database-first approach. Out of the box SimpleMembership is code-first.
i want to change datatype at UserId column in UserProfile table of simplemembership provider in my MVC 4 web application. because currently INT datatype is too small to store users so i want to change with LONG (bigint) datatype.
is it possible to do it ?
The schema for the SimpleMembershipProvider tables is fixed and you cannot change that. You will have to write a custom memberhsip provider.
But if you're gonna need to handle more than 2,147,483,647 (2.1 Billion users) in your system, the SimpleMembership provider is probably the last thing you're gonna have to consider as an option for this huge amount of data. So writing a custom membership provider is probably something you might need to consider anyway if you will be dealing with those kind of figures.
I have a web application using EF4. I am somewhat new to EF and now trying to implement change Audit.I tried to do this by trapping the SavingChanges event of the Context Class as below
partial void OnContextCreated()
{
this.SavingChanges += new EventHandler(TicketContainer_SavingChanges);
}
So the event handler accesses the changed records by the following
this.ObjectStateManager.GetObjectStateEntries(
EntityState.Added | EntityState.Modified);
This works fine and I am creating column level audit for selected tables. Every table/entity has an ID field which is an identifier with columnName="ID". So in my audit routine I simply accesses data from column with name "Id" to get the ID of audited record.
The problem I face is during insert . The new record has no ID yet as it is an identity column in the database and is always 0.
One solution I can think of is using GUID for all Ids.But is there a way to implement this using standard int32 Identity Ids?
thanks
When we insert data through EF the identity column is not generted while insertion. To get the Id of Identity columns we have to insert the data first then only we can get the Id of coulmn.
please go through the below which might be helpful to you.
http://www.codeproject.com/KB/database/ImplAudingTrailUsingEFP1.aspx
I don't now how many entities you have but in our own implementation of audit tracking we created a specific audit entity for each entity so we could link them together trough navigational properties and let the database set the identity keys.
If you use inheritance for your audit entities it's quit easy to query them.
Hope this helps :)
Identity columns are not generated while insertion. Once data is inserted then only you can get identity column data in EF. So, you can try some work around by getting Id after insertion and then populating audit table with that Id.
I am developing StudentApp in .NET 3.5 SP1 MVC Application.
I have two tables
Course
CourseID, course_Name
Students
studentID, student_Name, courseID(fk)
Now I made StudentApp.dbml which is having both table as entities.
As Foreign key will not be present in student entity,
I can not display courseID in student model, more over i can not generate add, edit, list views.
So tell me how to display courseID(fk) in student & i also want course name instead.
And also dropdownbox showing course name & storing courseID in edit view .
I'm pretty sure you have to load the foreign reference for each entity. Since I have no idea how you've constructed your API, I'll have to give you a pseudocode'ish example, but I think this is what you need to do.
List<Students> studList = [your_db_facade].SelectStudents() // Or however you retrieve your students
foreach (Students singleStudent in studList)
singleStudent.Context.CourseReference.Load() //CourseReference.Load() should be in the framework
Then you get the CourseID and name from the single student entity like
singleStudent.Course.CourseID
singleStudent.Course.course_Name
It could look slightly different for you, but I think the key to solving your problem is CourseReference.Load().
If your using LINQ-to-SQL and created a DBML file in Visual Studio then the foreign keys can be listed through the Course property in the Student object (automatically generated so since it is a one-to-many relationship from Student). Sort of like this:
var studentCourseIds =
from s in context.Students
select s.Course.CourseID;
Since your goal is to find the coursename then it is already accessible with Student.Course.course_Name.
Can you post your DBML? Also, DBML is used in LINQ to SQL (L2S) - EDMX is the mapping used in the ADO Entity Framework. Are you using LINQ to SQL or the Entity Framework (EF)?
No matter which one you are using - they both support Foreign Keys and you would get a property representing either side of the relationship - you don't need to do anything special (the Foreign Key must exist in the database, of course).
In EF, the foreign keys are called "navigtion properties" and they work a little differently to Foreign Keys in L2S. Nothing major, but updating them and "eager loading" are somewhat different.
Just drop the tables onto the map in the designer in Visual Studio (or generate using command line equivalents if you prefer).
Regarding Foreign Keys and Drop Down Lists (and other UI goodness) - I wrote a couple of blog entries on some approaches which might suit you. One part is located here and part two is located here.
if you create the correct relationship in your SQL server database, then when you add the tables to your DBML designer, the relationships will be copied across also and your code will link up automatically.