I've made a local database for a C# project:
I know basic SQL commands, but haven't worked with databases in C#.
What I'd like to know specifically is:
How to read from the database (query)
How to add and update rows
The database only consists of 3 tables, so I don't think anything fancy is needed.
First, you should learn a bit about various technologies and APIs for connecting with a database.
The more traditional method is ADO.NET, which allows you to define connections and execute SQL queries or stored procedures very easily. I recommend digging up a basic tutorial on ADO.NET using Google, which may differ depending on what type of project you're creating (web app, console, WinForms, etc).
Now days, ORMs are becoming increasingly popular. They allow you to define your object model in code (such as every database table would be a class, and columns would be properties on that class) and bind to an existing database. To add a new row to a table, you'd just create an instance of a class and call a "Save" method when you're done.
The .NET framework has LINQ to SQL and the Entity Framework for this sort of pattern, both of which have plenty of tutorials online. An open source project I really like is Castle Active Record, which is built on top of NHibernate. It makes defining ORMs quite easy.
If you have specific questions about any of the above, don't hesitate to post a new question with more specific inquiries. Good luck!
Update:
I thought I'd also put in one last reference as it seems you might be interested in working with local database stores rather than building a client/server app. SQLite allows you to interact with local stores on the file system through SQL code. There's also a .NET binding maintained by the SQLite guys (which would in theory allow you to work with the other platforms I mentioned): http://system.data.sqlite.org/index.html/doc/trunk/www/index.wiki
You can use SQLCE.
This blog will give you a good start.
http://weblogs.asp.net/scottgu/archive/2011/01/11/vs-2010-sp1-and-sql-ce.aspx
Here is a small tutorial that should be helpful to you.
You can make use of the SqlDataReader to read data
and the SqlCommand to Insert Update Delete rows from your tables.
http://www.dotnetperls.com/sqlclient
You could use it by adding following to your Startup.cs
services.AddDbContext<DemoDbContext>(options => options.UseSqlite("Filename=data.db"));
Related
New user so I hope I can tell you what I want ---
I have a information in my database. I need to get that information in a seeder class in C#. I would rather not have to re-type the whole thing one line at a time.
Is there any way for me to do this? I am using Visual Studio 2012 and Microsoft SQL Server Management Studio if that makes any difference!
For example, I have CategoryId, Category as my table headers and the table is populated with autogenerated ID's but I have put in lots of categories.
PLEASE remember I am a new user so break down your answers with lots of examples PLEASE!!!
Thank you!
Your question is rather vague.
If your general problem can be re-stated as "How can I easily turns rows of data in my database into objects in C# with as little code as possible?", then I would recommend learning how to use an ORM layer. I use NHibernate to great effect. It provides a way of mapping tables in a database to classes in C# and does a ton of CRUD (CReate/Update/Delete) work for you. The alternative is to do the grunt work of writing stored procedures, pulling values out of a data set and constructing objects yourself; all of which is very tedious without an ORM layer.
I am creating a C# application which will have to upload and read data from a SQL database. In school I learned the raw database calls but I am wondering if there is a free tool which lets me work easier and faster with the database call.
I also need to be sure that none is editing on the same line in the table at the same time so it could be nice if the tool also had something to ensure this.
Hope some of you have some great experiences
Take a look at Object Relational Mappers.
The favourites at this time a nHibernate and Entity Framework, but there are many others.
I am working on a personal project as a way of learning more about C# and .NET, specifically creating an application that utilises a database (MS SQL Server 2008 in my case). Whilst I appreciate there isn't always a definitive "right" way of doing things, given the choice between using an old technology/idea or a new one, I would rather use the new one. For example, one of my aims for this project is to learn, or at least familiarise myself with, WPF rather than using WinForms as I have done in the past.
On that basis, I've been muddling around without a great deal of direction with regards to saving data to my database and retrieving it. So far I've managed to get both those working using TableAdapters but I feel like they are the "old" way of working (my basis for this is that they are listed under Visual Studio 2005 on MSDN). Firstly, am I correct in this assumption? If so, what are the newer methods of saving and retrieving data from a database? I would be grateful of any pros and cons each method offers.
I've Googled and searched MSDN extensively but I don't feel like I am using the correct search terms as I have only succeeded in confusing myself.
I have .NET 3.5, Visual Studio 2008 and Microsoft SQL Server 2008 at my disposal.
Any guidance would be much appreciated.
I would agree that TableAdapters, DataSets, DataTables, etc. are the "old" way of doing things.
The "new" way would be Linq-to-SQL, Entity Framework or NHibernate.
Personally, I like to use a combination of Linq-to-SQL along with plain old DBConnections, DataReaders and DTO's where needed.
If you would like a newer way of doing Database access in .NET, I would recommend looking into LINQ to SQL or the Entity Framework.
There are many many many different ways to retrieve data from SQL Server 2008 using .Net.
Table Adapters are not a bad way; they are core to the .Net Framework, easy to get started with and reasonably powerful, although they do not perform quite as well as other options and often require more memory.
Basically Table adapters are good if your data is structured the way you want to view it. If you want to view data in a different way to it is stored you can do this with a table adapter but you loose the ability to write back changes to the database, this is OK if you are just generating a report.
If you want to view and change the data and the data is not in the structure you want to view it you need entity framework so you can query the data to get it into a different format and still have the ability to write any changes back. This is what the call the data from the server the MV to the display the VM
What is the best approach to build a small (but scalable) application that works with Sql Server or Oracle?
I'm interested in build apps that supports multiple databases, in the process behind the feature.
Using an ORM that supports multiple databases is the first step here. You could look at either NHibernate or Entity framework for example - both have oracle and sql server support. That way you should just have to swap out the database mappings to get the application to work on either DBMS.
Edit - thanks to tvanfosson, added the 'new' link for nhibernate.
In addition to the ORM comments; sometimes life is not that simple.
You must keep separate scripts for generating your tables, views, and stored procedures on both systems as they will differ.
You may have the need to do something tricky for performance reasons that is specific to one database platform. For example, making a new partition in Oracle.
You should try to do it at this level by encapsulating it in a view or stored procedure.
Your client code can call the stored procedure with the same signature on any database. You can write a stored procedure that does nothing or lots depending on what that databse requires.
My suggestion would be to use an existing (free) framework, like nHibernate, which abstracts out the dependence on the database for you. Alternatively, you'll need to define your own abstraction layer that is able to interact with drivers for either of the two databases.
as a complement to the other answers, you should tak a look at DbProviderFactories architecture in ADO.Net... a bit low-profiled but maybe useful for you.
As many people have pointed out, using an ORM could solve your problem. I've used LLBLGen with great success. Alternatively you can use the interfaces IConnection, ICommand and so on to roll your own ConnectionFactory.
I would use an OR/M. Most of these have support for many different database vendors and have a database agnostic language to do quering and the like.
I can recommend NHibnernate for C#.
Came across this:
http://www.eggheadcafe.com/articles/adonet_source_code_generator.asp
And wondering if this is the right solution as I am not that big of a fan of creating a class for every stored procedure or do I use Enterprise Library for ASP.net 2.0 project.
You definitely shouldn't be creating a class for every stored procedure. There are a number of approaches you can take to handling your database interactions. You should have a good look at the major frameworks out there and decide which one best suits you. The Castle Project solution is great, and relies on nHibernate (nHibernate). LINQ is a similar offering by Mircrosoft (LINQ Project). Both of these solutions are full ORM frameworks (Object Relational Mapping) and will generate dynamic SQL to persist your objects in the database. Each also has it's own quirks and likes you to structure your objects in particular ways. If you don't want to manage the SQL your system uses, I would definitely recommend one of these approaches.
I come from a database background, and prefer a bit more control over my SQL. In particular I like to have my interractions handled by stored procedures. I find this enables me to control both the SQL better for optimisation, but helps me manage database security in a more friendly manner. To accommodate this approach, I recommend something like iBatis (iBatis). iBatis isn't a full ORM, but rather a simple SQL mapper. The downside to my approach is that you need to write a lot more code (SQL), but I don't mind the trade-off.
Is there any possibility of upgrading to framework 3.5? if so take a look at LINQ to SQL and Entity Framework as this will accomplish alot of this for you.
If not then as long as it generates standard code that doesnt tie you into 3rd party libraries then you could certainly use it. At my workplace we have our own generator similar to this and it works well although we will shortly be moving to LINQ to SQL.
There are many ways of wrapping a database table in a C# class; you probably want to investigate a few alternatives before choosing between the one you've linked to and the Entity Framework.
There's a software pattern called the "active record pattern" which describes exactly this approach - one C# class for each table, with load/save methods like Customer.GetById(), Customer.Save(), and so on.
For ASP.NET 2.0, check out the Castle Project's ActiveRecord implementation and a third-party Visual Studio plugin tool called ActiveWriter that lets you generate class wrappers for your tables using a drag'n'drop interface.
You will need to determine at what point you need sets of data that are composed from your tables, and whether you want SQL to produce these with stored procedures or if your business logic layer will handle these. As Dr8k says, nHibernate will create SQL for you, but there is a learning curve with nHibernate. The ORM will be in control of how you are getting the data and depending on your environment and DBA's conmfort level you may other issues to overcome.
If you more comfortable with SQL, then there is another tool called SubSonic that will create wrappers ala Active Record for you while offering you the ability to use stored procedures as well. There is also a nice query tool with a fluent interface that you can use if you are not able to use LINQ.