I have one master & detail in my 'db1' and there is one column named 'EntryByUserId' in master table.
User table is available in 'db2'.
When all the tables are available in one single database we can directly get user detail by using include function. But here my reference table is in another database so in my case user object will return null value. So anyone please help me to achieve this.
I have created multiple dbcontext in my project but don't know how to get this.
Below is the code we use when all tables are available in single database.
dbcontext1.tbl_Master.Include(m => m.tbl_Detail).Include(m => m.tbl_user)
.AsNoTracking().FirstOrDefault();
One option to accommodate this cleanly, especially for something as frequently accessed as a "User" reference for something like reporting on CreatedBy or ModifiedBy tracking on rows would be to implement a view within Db2 that lists the users from Db1. Then in your main application context you can map a User entity to the view rather than a table. I would put guards in your DbContext and entities to discourage/prevent modifications to this User entity, and leave maintenance of users to a DbContext overseeing the Db1 tables.
If this is something like a multi-tenant system with a system database for authentication and separate DBs per tenant which are tracking things like CreatedBy against records, I would recommend considering a system to inspect and replicate users between the auth database and the respective tenant databases. The reason for this would be to help enforce referential integrity for the data and the user references. The issue with the view approach is that there is no constraint available to ensure that a UserId reference actually corresponds with a row in the Users table over in the other database. It can be indexed, but not constrained so you have to handle the possibility of invalid data.
Related
He guys, so I need a little help with my database model for an mvc project I am working on.
Here is the situation:
I have a table called dbo.Clients that has the columns ClientName, PlanName, PlanPrice, PlanStartDate, PlanEndDate, and IsArchived.
For the fields ClientName, and IsArchived are only going to have one value in them that is subject to change. However, each client will have multiple PlanName, PlanPrice, PlanStartDate, and PlanEndDate values.
I have a ClientModel, ClientViewModel, ClientRepository, ClientService, and ClientController set up that successfully puts values into the database from the view.
The problem:
The way that I have done this is that I can only use one value for PlanName, PlanPrice, PlanStartDate, and PlanEndDate. For example lets say a client has bought Plan 1 and Plan 2 but I cannot store more than 1 plan.
What I want to do is make another table called Plans but I'm not quite sure how to use that in the MVC way to storing multiple values per client.
You need two tables. One will be a client master named something like Clients with the Columns Id, ClientName and IsArchived.
The other table will be something like ClientPlans with the columns ClientId, PlanName, PlanPrice, PlanStartDate, PlanEndDate
Ensure there's a Foreign Key relation between the Id in the Clients table and the ClientId in the ClientPlans table.
This can be refactored further to have a separate table for Plans (Id,PlanName, PlanPrice, PlanStartDate, PlanEndDate) and a transaction table called ClientPlans containing ClientId and PlanId with the appropriate relationships set.
Hi I am working on a calendar application using Ruby on Rails. Rails is database agnostic, so in development I'm using SQLite but in production I am looking to use PostgreSQL.The current obstacle that I am facing is with the way I am designing my database schema.
First I have a users table that holds information such as login info and email. Each user has_many plans.
Then I have a plans table that belongs_to users and each plan has an event it references, the date, start time, and end time.
So the plan tables would reference the events table.
Here is my issue:
I would like to have two event tables. One is custom events. The other is default events.
The default events is just a list of common events already defined so the user can already select from a list. The custom events table is a list of events created by a user that references their id.
Here is my solution:
Would it be sufficient to add a new boolean column to the plans table called "custom". And if it is true then the event_id (in plans table) will reference the custom events table, and if it is false then it will reference the default events table. Is this a valid solution and if so, how would I implement it into my Rails application?
Thank you for taking your time to read my question. I am sorry I am an idiot. I am practicing everyday to be better.
Try to not think in terms of tables first, but in terms of classes and the behavior of their instances. What would matter most in the end is not how many tables your design has, but whether the responsibilities have been correctly attributed to the different classes in your model.
In this case it looks like you need two different classes, because some events will belong_to a user and other won't. The former will be created, modified and deleted by that user, and the latter will be managed by an admin. The instances of those classes can be stored in the same table using STI (Single Table Inheritance), with a string column named 'type' to enable Rails to store the class for each instance. The UserEvent class will belong_to :user, and the DefaultEvent won't. Both classes can extend Event, which in turn extends ActiveRecord::Base.
Please let me know if you need additional clarification.
We have a table (AttendanceType) in our database which have many fields with multiple options. this multiple options are defined in single table. So, instead of creating separate Option table for each option we have single table (Option_Data) with key to identify each option type (Record).
Example : AttendanceType table has following fields
ID
Description
Category (Payroll / Accrual)
Type (Hours / Days)
Mode (Work hours / Overtime / ExtraHours)
Operation (Add / Minus)
These fields have options (data as shown above in brackets) which comes from Option_data table. We have created separate views from this Option_data table example: vwOption_Attendance_Mode, vwOption_Attendance_Operation etc.
Now, how we can link this view in breeze so the reference data come automatically.
We are using EF6, SqlServer, Asp.Net WebApi. When the table relationship is defined in SQL Server Breeze works perfectly and manages the relational data. In this case we cannot define relationship in SQL Server between Table and Views.
How we can code it so Breeze can manage the relational / reference data for us? If you require further clarification please let me know.
Edit # Jay Traband : Let say a single table (ie: AttendanceType) has fields which get reference/lookup data for its field from Views. How in breeze we can relate them (table with views), as in SQL Server we cannot.
My reference points is when Tables are related breeze does excellent job. I want to achieve same with table and views.
Breeze gets its metadata (including the relationships between entities) from EF. You'll need to tell EF about the relationship between the tables and views, even if there is no such relationship defined in SQL Server. This SO post provides some clues, and this blog post gives some related information about creating relationships in the designer.
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 have a following domains
User (in database called usermanagement) and
Account (in another database xyz)
Its an old system so i cannot really change the architecture of the system. I have been assigned task to implement a system that a certain users can only access certain accounts. This is a classic case of many-to-many relationship but the problem lies in the fact that these two domains are in two different databases. I googled if that was possible but i realized that it was not possible. So I now am thinking of creating a custom join table to store info on which user are allowed access to which accounts. The table can have two columns 'accountId' and 'userId'. So for this, do i have to create a new domain in grails or is there any cleaver way of doing this ?
Thanks in advance.
If you create joinTable in which DB you are going to create it and how you are going handle updates in main (Account,User) tables and ceep your join table up2date ?
I think (for this case) you don't need join table, you need handle business logic in application level.
You cane have 2 Domain classes each one pointed to different dataSource(DataBase).
http://grails.org/doc/latest/guide/conf.html#multipleDatasources
As I searched for solution of this, I did not find any sustainable solutions. I eventually narrowed down the probable solutions to two:
1. Create a domain table (only) using sql, some sort of patch and use hard-coded queries in grails to write and access data to and from the table.
2. Create a domain class like AccountUser having properties clientId and userId
I choose the 2nd option, I wrote some additional methods and created a service to return user and client instance and I am done ! Anyways, thanks guys.
If the databases are "visible" to each other (on the same server or there is a db link between them), you should be able to map the domain classes using the fully qualified table names ('schema.tablename') in the mapping closure.
psuedocode:
class User {
static mapping = {
table "usermanagement.user"
}
static hasMany = [Account:accounts]
}
class Account {
static mapping = {
table "xyz.account"
}
}
http://grails.org/doc/latest/guide/GORM.html#tableAndColumnNames