I'm working on an application which was previously developed with EF, SQL Server, C# and WinForms. For some reasons we need to remove SQL Server and use some and put data in some other container like XML, Excel sheet or in memory classes.
DAL was designed using EF with repository and UOW pattern. Can you please suggest me what can be the best way to migrate and what format will be easy to transfer data?
Since the data access is decoupled into a repository you should be able to write a new repository instance that will allow you to retrieve your data in its new format. Specifically if you wanted to hold the data in XML you could just write a new repository that uses Linq-to-XML to retrieve your data.
I don't know of a good quick way to transfer your data from SQL Server into XML. If I were doing it I'd probably write some custom application to make the conversion, but I suspect there are better solutions out there for this type of migration.
Your question duplicates this questions:
Entity Framework with XML Files
How to use Entity Framework 4.0 with Xml or in-memory Storage (non-SQL)
There seems to be a provider for virtuoso xml:
http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtAdoNet35Provider
Some hints can be found here:
http://social.msdn.microsoft.com/Forums/en/adodotnetentityframework/thread/6f6164f6-fced-43de-b3fc-eccbd74dd482
http://blogs.msdn.com/b/adonet/archive/2009/11/05/model-first-with-the-entity-framework-4.aspx
http://en.wikipedia.org/wiki/ADO.NET_Entity_Framework
EF ist basically developed for database abstraction. You will need to write your own xml database provider if you try to strore XML instead.
Your options are:
move to SQL compact (but not in XML)
use XPath and rewrite your code
use Xpath for your own database provider
Be aware that your xml file size and speed depends on the amount of data! Using multiple xml files can end up in a mess.
Related
Here's our situation.
We're receiving a dump of relational data in Access 2007 format. There are quite a few tables involved. We're writing a console app in c# to run various queries against this data. We only need read-only access - we're not updating the Access database.
I haven't used Access in a project since pre-Linq days, and I'm hoping we don't have to go back to coding strings of sql against an ADO.Net connection just because the database is Access. I gather Linq 2 Sql is out of the question, but might Entity Framework be usable?
How would you approach this problem?
EDIT: The console app will be dropped by a business analyst into a folder containing the Access database, and when run will generate a text file created by querying the data. So unfortunately it's not an option to transfer the data to Sql beforehand!
If you must keep the data into Access, you can pull it into a Dataset via ADO.NET, and then use the LINQ extension methods that work against a Dataset to work against the data.
It's not nearly as nice as working with SQL Server, but it does work.
I would fully import the data into Sql Server, after which I would gleefully destroy all copies of the original Access file. Then you could get as Linq-y as you like.
Linq2Sql no, LinqXml yes! How hard would it be to dump the access file to xml?
I'm not sure I understand the question, but have you considered a SQL Server linked server to the Access file? You could then use SQL Server to do the manipulation. I don't know what the limitations/pitfalls of that are, but it's a solution often suggested when there's no good direct way to manipulate the Jet/ACE database.
I'm faced with the challenge of writing an object persistence mechanism that serializes/deserializes to a SQL database and XML files.
For the sake of illustration, imagine I have a graph of objects that has a single root object. Maybe a "tree", for example, which has all manner of child objects -- leaves, brances, nuts, squirrels, birds and the like.
I need a suggestion for an architecture that seamlessly moves between loading & saving a "tree" from a file and/or database. It needs to be able to load a "tree" from a file and save it to a database, or the other way around.
I'm currently using Entity Framework for my SQL persistence, and I'm happy enough with it. For the XML I'm using XDocument, which I also like a lot, but I'm wondering if there isn't some framework out there that already does all this.
Unless you want to do querying on your objects in Sql Server (or there are other sources that may update/manage relational data), using EF to convert into relation schema is a bit overkill. If all you want is to persist your object graph in different mediums then you should consider runtime serialization or DataContractSerializer. Essentially, you will get binary data or XML that you can dump into any storage medium including Sql Server. This will free you from changing relation schema in sql server when your object structures changes. However, you must consider versioning your objects while going from serialization approach.
You can try using the older, yet very nice XmlSerializer.
ps. need to watch out for anything Entity Framework may require from you when loading an object you serialized to a xml file.
Are there any strict requirements around the entities being saved in XML format? If not, another option could be to use SQLite (http://sqlite.phxsoftware.com/) with the entity framework when you need local/filesystem persistence.
So far all the serialization examples I have found on the web are related to storing arrays or list in a file. With each class of object having to be serialized into their own file such as a ".bin". The root of my problem is that I want to have the information for my product local stored, but I'm so use to working with sql. It's hard for me to visualize how to store information locally. If C# is anything like asp I should be able to connect to an Access database, but that pretty much defeats one of the ideas of serialization which is user non-readability. Is there a serialization method similar to using table and fields or at least allowing you to store all user information in one file?
You could use a ADO.NET DataSet that is serialized and stored locally. It will contain all of the data structures that you're familiar with and allow you to query the data the way you seem to want to and if you serialize it with a Binary Serializer, it will be unreadable to end-users.
Also, you could look at SQLite as an alternative to using DataSets.
SQLite is a software library that
implements a self-contained,
serverless, zero-configuration,
transactional SQL database engine.
SQLite is the most widely deployed SQL
database engine in the world. The
source code for SQLite is in the
public domain.
NHibernate with SQLite is a great combination as well.
Cheers.
Check out NHibernate. That will give you your 'database-like' storage.
If it's human-readability you're after, consider serializing your objects using XML. .Net has decent support for serializing (and deserializing) objects using both XML and binary formats.
The tutorial I used for learning serialization in C# is this CodeProject article.
Update:
I misread one point you made: serialization does not necessarily mean human-readable or not - if you decide to serialize, figure out if you want the data readable or not. Binary serialization is likely to be more compact and less readable.
we have a relational database with some data and we need to offer the content of the database via XML web services. We also have to enable users to get parts of the XML representation using XPath (also later there may be a need to modify data indirectly using XML representation of the data with XQuery). Is there a simple way to achieve this in C#? The user will be known XML schema of the data.
Keywords for web search also appreciated.
Read up on OData ;) A lot better than bad web services. Full tooling support in .NET (LINQ integrated) it is a semantical way to expose data via intelligent web services.
There are a few ways I discovered, although I couldn't find much data.
One is to use an SQL query which returns an XML, the other is to use DataSet class with some of it XML processing possibilities. DataSet also supports XPath queries.
I have to store relational data (text, numbers and pictures) into an XML file. I want to maintain the relationship between data and the tables structure.
How do I go about doing that?
My Windows Mobile application use Windows Communication Foundation (WCF) to get data. Once it gets the data it stores them into an XML file.
The WCF use ADO.NET Entity Framework to data retrieve.
I'm going to use SQL Server 2008.
The data will be use to show it on application. I don't want to use SQL Server CE to store data because it's slower. Maybe, instead of using XML file I can use text plain files to store texts and numbers, and image files to store images.
In short, XML will be a way to store the data instead using SQL Server CE or WCF.
Thank you!
Thanks for the additional detail.
My suggestion is first, try SQL Server CE. It might not actually be slower for what you're doing. The time you save in not reinventing the wheel might be better spent in speeding up other parts of your application.
For the rest, assuming you don't need to store the data for long, nor do much with it, I'd suggest copying the data from the Web Service return type into a DataSet. The DataSet type has a WriteXml method that can save the data, and a ReadXml method that can read it back in.
While it's a little ambiguous what is needed, you can try looking into 'FOR XML EXPLICIT' under SQL Server. This will include relationships. Link: http://www.eggheadcafe.com/articles/20030804.asp
what about a dataset ? define the tables and relations, load the data into the dataset, and save it as XML (WriteXml method)
Define your XML format as an XSD. If you use Visual Studio use add new DataSet and the "custom tool" will automagically create a strong-typed set of classes based on DataSet. You can define tables and relations with constraints. It is easy to do in Visual Studio. If you are Visual Studio averse, you can create the XSD by hand and use xsd.exe to generate your code.
Once you have the strong-typed DataSet filled with data you can serialize it to an XML stream by calling WriteXml.
What do you mean by, "maintain the relationship between data and the tables structure"? Are you talking about more than maintaining the ID of a source database record in an attribute of an XML node? What do you need to do with the XML data once you have it? Will it be edited and have to be re-applied to the database?
More questions than answers from me....sorry.
What SQL Server are you using? Some servers allow you to request an XML response for a query. That could save you a lot of work.
EDIT: Since you have specified that you will use MSSQL 2008, you may be in luck. In MSSQL 2005 and later there is a "FOR XML" keyword which allows you to get results as XML. Give it a try.