I have to create architecture and procedures to connect Visual Studio c# programs with the database on the IBM AS/400.
I'm looking for different possibilities, I think that services Rest is the best choice but I have not yet decided how to connect them with the AS / 400.
Does anyone have experience about this? Could Entity Framework be a valid option? What about IBM.Data.DB2.iSeries data provider?
I've to do "simple" CRUD operation, i'm in a local network without permission problems or users limitations.
From my experience, you need to install the ODBC drivers of the AS/400 in order to be able to establish a connection between the application and the database. I have not tried to use Entity Framework with an ODBC driver, but this link says that Entity Framework does not support ODBC connections. Your option here is to use the OdbcClient classes offered in .NET, in order to establish the connection between your application and the AS/400 database.
REST or SOAP or ODBC or others could be "best" for different uses and different clients. In most programming categories, there is no such thing as "best" until all significant requirements and constraints are known.
Please clarify what the objectives are. Are you looking only for database interoperability? (What kinds of actions?) Is this also application 'command & control' that invokes remote application functions? What things need to happen? How does networking fit in? Who are the users?
The more elements you can consider, the better chance of getting something right.
Related
After much Google searching and at the risk of asking dumb questions, I could use some help. I’m developing a C# WinForms client application using ADO.NET to read/write data from a SQL Server 2012 database located on the Internet. That same application also needs to upload/download data files. The client application will only be used by a few employees (ever). The employees are all in different locations. The database is only about 20 MB. There will be about 100 data files totaling about 300 MB accessed individually on a periodic basis. SQL Server 2012 is running on a (non-virtual) Windows Server 2008 R2 machine which we have full control over. The client application will be running on Win-XP and Win-7 machines.
Priorities are 1. Internet security – keeping hackers out of the Windows Server machine and off the client/server communications. 2. Performance. 3. Simplicity. Corporate security and scalability are not issues. Also, performance is not that important if the solution is overlay complicated.
Two related questions I could really use help on:
Given the above priorities, what is the best way to communicate with the database? The only two options I’ve found are exclusively; a WCF service or directly through a VPN.
And again given the above priorities, what is the best way to upload/download data files? I’m sure there are many options for this using VPN, WCF, FTP; but I don’t know any specifics. Also, using a SQL Server 2012 FileTable looks promising but I’m not sure how that works over the web. Backup/restore plus being able to do a full-text search over the data would be nice features but not requirements.
I know what a VPN is but have never used one for these purposes. I know there are some security issues with PPTP, but we won’t be upgrading the XP machines for a while. I know what a WCF service is but have never written one. I also don’t know if SOAP or REST is better in this instance. I’ve built a FileTable in SQL Server, but I don’t know how to access the data remotely. I have decent knowledge of C#, ADO.NET, and SQL Server.
I realize these are big questions with subjective answers. Still, any ideas or a shove in the right direction would be greatly appreciated.
Keep it simple and use standard mechanisms. My recommendation is as follows:
Build a WCF service that is capable of performing the operations you want. You can build a SOAP or RESTful service. My general guidance here is to build a RESTful service because you're transferring files and this is much more integrated with REST. With SOAP you have some setting you're going to need to fiddle with to transfer large files.
Use SSL to secure the service, keep it simple. A VPN is an added layer of complexity and very likely not needed in this scenario. Further, it will only make the experience for the users less friendly.
I would not recommend using the FileTable in SQL Server 2012 for your needs. You own the server so when you send and receive files it will be much more straight forward to deal with the file system.
You can also build a simple forms authentication process that creates a session key for the user and passes it back. I'm not sure this is necessary, but if you need that extra layer, just make that one of the operations. Then that session key can then be passed into each method and validated before performing the operation. This will be safe because you're using SSL.
Here is a tutorial that will help walk you through building a RESTful WCF service, and it's fairly new.
My recommendation would be to deploy a VPN server to provide the security you are looking for. There are a number of good VPN servers available, and a Google search should provide a number of options at varying price points.
Once you have deployed the VPN server (and clients to all computers not on your local network that you would like to be able to access the database), you can use ADO.NET to access the database. ADO.NET will work seamlessly behind the VPN.
From the context of your question I am assuming that the files are stored in a file system outside of the database, and the database merely references the files. If this is the case, you could use any number of options for downloading the files, but FTP is a time-tested, easy-to-implement solution. There are others that may or may not work better in your situation (see here for a few options).
I'll try to keep the question simple and short - what are the best practices when publishing a windows forms application which is using a SQL Server database?
Using ClickOnce with prerequisites I can enforce SQL Server Express installation, but what if it's already installed? How do you build the connection string? How do you find the names of the instances of the server? What kind of authentication should be used - Windows or SQL? Can this process be automated or is user interaction inevitable?
Adding an answer since this is the way you decided to go anyway, glad to help :)
You could also consider using SQL Server Compact which requires no setup and runs directly in-process with your application. Of course does not offer all features of SQL Express so really depends on your needs.
Have a look at: Microsoft SQL Server Compact 4.0
Note: if you could easily get rid of your triggers either you have cut functionalities or you got rid of things you do not really needed. I am old school and never use triggers, they are ofthen misused, seen people creating triggers just to set a default value in a column because did not know could have used the default.
Hmm, in this scenario I would say you would have to take into account the use of the database, if the database is connected up to a network which will support many users authentication would be needed and would inevitibly face some kind of user interaction.
I really don't like the concept of opening my SQL server(s) to the internet - even if I can lock down the firewall. However I've always been working directly with databases. I'm building a system now which involves 1 SQL Server database, a web application in ASP.NET/C#, and a few windows applications in Delphi XE2. But from the beginning, I'd like to put some sort of 'filter' around the database so I don't have to open it up.
I know there are many things out there for this, but don't know anything about them or what to get for my scenario. I'd like to keep it native to SQL Server; I don't plan on using any other type of database engine.
It needs to be connected from client to server by other means than the standard SQL connection, like a filter. It creates its own encrypted packets and transfers data its own way. I will have a wrapper class for both Delphi and C# which will pretty much be identical - and be able to stream its data into the DLL to interact with the DB.
Now there are three different ways I can go about this...
Complete SQL Server wrapper, most likely no source code, might even have its own language (I don't want to pick up another database language), and independent from my project as its own separate system.
Open-source wrapper, preferably in Delphi (XE2), or if not then C#, specific protocols for my system, entirely dedicated to my project, and in the final form of a DLL which can be used on both the Website (in C#) and the applications (in Delphi).
Web Service - however I only have 1 hosting spot (Paying for 1 site, 2nd site will be a double charge on me). I can't host any additional web services or windows services; it has to be integrated with the website. Otherwise, I would have done a web service for this.
I would much prefer the second option, and do not want to go anywhere close to the first one, and can't do the third one at all.
So any good libraries for database layers? And might there be some already installed in Delphi XE2? I'm thinking maybe an encrypted XML packet?
As an example, let's say I have a table for 'Customers'. In both my website and applications, I should never have any SQL script like select * from Customers or no SQL script in general. Instead, I will have a wrapper around the database. So I can call a function such as DBGetCustomers(Conditions: TGetCustomersConditions): TDBCustomers; where TGetCustomersConditions is some way of filtering the query, and TDBCustomers represents the results from the query.
There could also be a function DBAddCustomer(Item: TCustomerToAdd): TInsertSuccess; where TCustomerToAdd represents what to insert, and TInsertSuccess represents any result, such as error message(s) or rows affected. I do not intend for it to be working exactly like this, but just to explain the concept of any wrapper in general. When the app sends to request to the server, it still has not converted anything to a SQL Query. By the time the request gets to the server (which is able to connect to the database), then the server alone decodes everything to the SQL query.
What's the problem even if you have just one "hosting spot"? A web service is just a "site". And a web server can easily host multiple site even with a single IP address. Anyway, what you're looking for is an "application server" in a multi-tier design.
While Java invested heavily in that direction, MS did not. Delphi has Datasnap, which is a so-so framework, don't know if the new "restful" interface is easily callable from C#, it looks to have security flaws though. The .NET way of doing it is using WCF, as long as it uses a standard protocol you can call if from Delphi has well.
You could also look at RemObjects DataAbstract. It's not open source, but it is a mature library.
One of the 'traditional' ways to do this is via webservices (although this technique is now considered by some to be a bit dated).
One disadvantage is that it is not a generic wrapper you can throw around the database, but it has the advantage that you can limit access to the database easily to specific stored procedures for example, which will maximise security, and is a standard technique if you wish to provide limited authorised access to external applications.
If you already use a ASP.NET C# web application, you could also add a WCF (Windows Communication Foundation) based web service to your web site. This can provide database access to external applications, which need to connect the web service somehow. It should even be possible to use the same HTTP standard port for both the normal web site pages and the service, by mapping the web service to a specific context path like www.example.com/services/servicename
Kbmw allows you to make a ntier db architecture.
However since you have a web application involved, a better option would be WCF (as already suggested)
I am looking at writing a WinForms app and getting stumped over what seems to be simple issue.
There is a server and database (SQL Server) Open ports are HTTP, HTTPS
There is a WinForms client. It needs to connect a TCP/IP stream (possibly HTTP, SOAP, REST) to the server.
Sometimes the WinForms client goes off-line and then the WinForms client stores its data in a database.
When the WinForms client goes on-line to server, it synchronizes data to the server, gets all the latest data from the server and updates local database.
How do I do that?
Newbie question
As you've conceded, this question shows you might not know where to begin looking for how to architect this kind of application.
I'd start here: http://msdn.microsoft.com/en-us/library/ms973279.aspx
The offline architecture you've described is a little tougher for a newbie than not supporting this, consider making the application only work online first, then add offline functionality.
Also, if you have a web server you will almost always use HTTP, SOAP and REST are strategies that sit on top of HTTP. I cannot recommend that a new developer look at any server communication using direct TCP/IP.
Edit: Answer to related question - there are tons of ORMs and service builders, not a lot of them have built in support for offline workflow but ODX does, but it might be a bit out of date. NHibernate and any of the projects in the Castle Project are very popular components for what you're looking to do also.
No idea how actively this is still being supported by Microsoft, but you might check out the Smart Client Software Factory, it seems to support offline mode and smart reconnecting like you need.
http://msdn.microsoft.com/en-us/library/ff709809.aspx
You could approach this with a 'Service' mindset - Write a WebService (preferably a WCF service) - that forms the synchronization tier between your Winforms app. and remote database.
So, you would have your
1. Local WinformsApp. with a local database (as functional/lightweight as you want it to be)
2. WebService
3. Remote app./DB
Here are some links to tutorials/resources:
http://www.codeproject.com/KB/architecture/three_tier_architecture.aspx
http://services.community.microsoft.com/feeds/feed/query/tag/n-tier/eq/tag/visual%20basic/eq/and/locale/en-us/eq/and
http://msdn.microsoft.com/en-us/library/bb384570.aspx
http://msdn.microsoft.com/en-us/library/bb384398.aspx
IMHO this isn't usually as simple as it may sound
If you were able to go DB to DB, then SQL replication could be the simplest mechanism for synchronisation.
However, since it sounds like you are using a SOA approach, you might need to look at frameworks which have offline support built in, such as the Ent Lib Composite Application Block and Smart Client Software Factory
You might also look at using Queues (e.g. MSMQ) to accomodate network connectivity problems.
Microsoft Sync Framework (http://code.msdn.microsoft.com/sync) + WCF solution here:
http://code.msdn.microsoft.com/sync/Release/ProjectReleases.aspx?ReleaseId=3762
Database synchronisation is not an easy task to get started with, by any means. Good luck.
Generally, you need a local database, or at least a local cache.
I am trying to connect to oracle database. I am able to connect to it through a local SQL Developer tool by sticking something in the oranames.tns file.
My question is that i will be deploying this website to a number of places. A few questions:
What is the simplest way i can use to connect to this database and do very basic queries. I see some examples that have me referencing oracleclient dlls. Other methods not? Is there a best practice here?
Am i going to have to update the oranames.tns file on everyone on of the machines that i deploy to ? is there any simpler way
1.
You can use the Oracle data provider that comes with Microsoft, but I recommend using ODP.Net. It's best to use native libraries when possible since they are usually optimized better, at least in my experience.
2.
You only need to configure the tnsnames.ora on the server, because the server is what's going to be handling the DB connections, not the client PCs (assuming that this is a MVC website).