I'm new in developing in MVC and I have some doubts in how to build the Models. I don't know if I must build them in terms of Database Tables or in other terms.
I have for example this 5 tables:
Domain
Category_Domains
Countries_Domains
Categories
Countries
How can i Build a Models to do actions in these Database Tables. Should I built the SQL commands to Insert, Delete and Update for each one of these Tables or I should do other thing than this?
Sorry if I not explain well.
The best advice I can give you is to look into the entity framework. Using this framework, you can create a data connection to your SQL database and the framework will create your model based on your table structure, including relationships.
Doing this will ensure your database is modelled correctly and kept in sync at all times
Related
I'm am currently developing one project of many to come which will be using its own database and also data from a central database.
Example:
the database "accountancy" with all accountancy package specific tables.
the database "personelladministration" with its specific tables
But we also use data which is general and will be used in all projects like "countries", "cities", ...
So we have put these tables in a separate database called "general"
We come from a db2 environment where we could create foreign keys between databases.
However, we are switching to MS SQL server where it is not possible to put foreign keys between databases.
I have seen that a workaround would be to use triggers, but I'm not convinced that is a clean solution.
Are we doing something wrong in our setup? Because it seems right to me to put tables with general data in a separate database instead of having a table "countries" in every database, that seams difficult to maintain and inefficiënt.
What could be a good approach to overcome this?
I would say that countries is not a terrible table to reproduce in multiple databases. I would rather duplicate static data like that than use more elaborate techniques. There is one physical schema per database in sql server and the schema can not be shared. That is why people use replication or triggers for shared data.
I can across this problem a while back. We have one database for authentication, however, those users have to be shared across multiple applications some of which have their own database.
Here is my question on this topic.
We resorted to replication and using an custom Authentication/Registration service agent to keep the data up to data.
Using views, in what Sourav_Agasti suggested in his answer, would be the most straight forward approach for static data. You can create views and indexed views and join data from databases on linked servers.
Create a loopback linked server and then create a view(if required, on each database) which accesses the table in this "central database" through this linked server. There will be a minor performance impact but it more than enough compensates by being very simiplistic.
I'm creating a new visual studio web site using MVC4/webapi that will go against a database of 75 preexisting tables (not perfect in terms of foreign keys, etc.). I'm thinking that I will create an ado.net entity data model and select all my tables. then, when my tables change I will do the "update model".
With my linq2sql projects, I always ran sqlmetal against all my tables all the time to keep things in sync and that worked fairly well.
Is my plan to have all my tables in one ado.net entity data model reasonable? what pitfalls might I run into? Is it better to have lots of ado.net entity data models? I've tried having multiple ado.net entity models in other projects and I seem to constantly be getting my connection strings doubled in my web.config.
I did do a search on SO and did not find any discussions that directly addressed my concern.
If you followed your plan, you would miss out on an opportunity to have an entity model simpler than your database model:
Your application almost certainly doesn't need all 75 tables.
You would be missing the opportunity to consider a series of 1-1 tables as a single entity
You would be missing the opportunity to use inheritance in your model
You would be missing the opportunity to keep junction tables out of your model
You would be losing one of the greatest advantages of Entity Framework over LINQ to SQL: it does not need to stay one-to-one with the database.
I am working on a asp.net mvc project and using Linq for all my data related operations. In such cases, do I need to define relationship in the SQL Server database ??
I am using Entity framework and Linq so I think it doesn't matter if I create an E-R diagram(i.e defining relationship) or not.
By 'define relationship' I assume you mean 'Foreign key constraints'. It is always advisable to define constraints in order to maintain data integrity. You should also consider that the database for your project could probably be used by other applications in the future which might be based on other technologies than EF.
If you have relations in DB they will automatically be imported in your EF Model but you always have an option to create the associations manually in the EF Designer if you don't have relations in DB.
See How to manually add association in Entity Framework
All,
Is there some setting that I can tell hbm2ddl to run a view creation statement instead of create a table when generating the database schema?
I'm creating my database schema using the wonderful hbm2ddl tool, but I have one issue. I need to flatten some of the tables into views to aid searching the database, and hql would be overly complex a solution. I've created Entity objects pointed at these views, in order to fetch search results via hibernate. This all works fine, until hbm2ddl is used. In an empty database schema, hbm2ddl will create the database schema based on the jpa annotations, unfortunately, it will also create my views as tables. Is there some setting that I can tell hbm2ddl to run a view creation statement instead of create a table? In lieu of that, is there a way to tell hbm2ddl to skip table creation for an entity (exclude, or something)?
Thanks!
To my knowledge, and this is unfortunate, Hibernate doesn't support things like creating views instead of tables nor validating a schema containing views. See issues like HHH-1872, HHH-2018 or HHH-1329.
I am planning to use ASP.NET MVC2 implemented membership system to manage users. Database that uses application should have tables that are related with these users. Is it possible to use two different databases and make relationships (foreign keys) between them or I will have to merge these two databases into one?
Thanks,
Ile
It is NOT possible to put up relationships between databases. You CAN use triggers to ensure relational integrity.
Otherwise I would say: all in one database, put them into different schemata.
I would put membership/roles in a separate database. I don't think having foreign key constraints is that useful. Its better decoupling if you go through the membership API rather than join with the tables directly. The only thing in the membership database you might need to look up often is the username. If thats becomes a performance problem I'd probably just create an lookup table, either in memory or in a lookup table in the other component's database.