I have a C# WPF program that needs to display GridView and 2D graph data which initially will come from a hardware device. I also want to continuously (or frequently periodic) backup this data to an XML file on disk. What would be the easiest way to implement this in visual studio? Should I create an XML schema first, or use the dataset designer? Should I bother with datasets at all or would it make sense to eliminate them and write my incoming data directly to xml?
I would recommend:
Plan a structure of an XML ahead. Create a simple empty file to help you along the way.
Create a data serialization provider as well as the interface that it will implement. In your case it will be an XML provider (who knows, you may need to save the data to a database in future. You should plan ahead for that.)
Write a custom class that serializes your poco domain objects into an xml using LinqToXML.
Related
Currently I'm working on an application to import data from different sources (csv and xml). The core data in the files are the same (ID, Name, Coordinate, etc.) but with different structures (xml: in nodes, tables: on rows) and in the xml I have additional data which I need to keep together till the export. Additionally important to say, I need for the visualization and modification just a few data but I need all for the export.
Problem:
I'm locking for a good structure (database or what ever) where I can import the data at run-time. I need to have a reference to the data to visualize and modify them. Afterward I need to export the information to a user specified file type. (consider the image).
Approaches:
I defined a class for the csv schema and mapped the necessary information of the xml to it. The problem occurs when I try to export the data because I have not all data available in the memory.
I defined a class for the xml schema and mapped the information from the csv to it. The problem is in this case, that the storage structure bases on the schema of the xml and if this xml schema changes, I need to change the whole storage structure.
I'm planing now to implement a sql database with entity framework. This is not the easiest way but it seems to be state-of-the-art and updateable. The thing is that I'm not very experienced with databases and the entity framework. That's way I like to know whether this is a good way to solve this problem.
Last thing to say: I would like to store the imported data just once and would like to work with references to this source. This way I can export the information from this source and I'm certain that I have the current data.
Question:
What is the common way to solve such storage problems. Did I missed a good approach? Thank you so much for your help!
My program should:
Load a data table from a legacy raw data file.
Provide an interface to display, filter, graph, etc.
My approach is to create an in-memory database as a DataSource for binding the filter controls, results grid, graphs, etc.
Question:
What is the simplest way to define and populate this in-memory database?
Edit:
I only have a minimal knowledge of LINQ. In the past, I'd always been able to just drag a database table or query into the form or webpage. Visual Studio would create the DataSet, DataTable, DataSource, etc objects for me.
... where do I define this structure (an XML file, in-code, wizard, drag and drop)? what data objects do I need? etc
You could create classes containing the necessary properties and then simply parse the file and populate those classes in-memory. Here you go, you've got an in-memory database.
I only have a minimal knowledge of LINQ
Here's a good start for you: http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b
where do I define this structure (an XML file, in-code, wizard, drag and drop)?
If you want to store the data in-memory define strongly typed C# classes that match your data.
what data objects do I need?
That would entirely depend on what information you have in your file and you want to handle.
I'm new to windows app and I would like to know what the best way to save a small amount of data, like 1 value a day.
I'm going for the text file because it's easy, but I know i could use MS Access.
Do you have other option ? Faster or better ?
Since you are already considering using a MS Access database, I would recommend using SQLite. Here's a quote from their site (SQLite Home Page):
SQLite is a software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine.
It is really very easy to use - no installations required, you simply need to reference a DLL.
If you need to read it then use a plain text file.
If you need to read the values back into the application then serialize to an XML or binary file by making your user data serializable possibly by having a List of values in your object.
How do you want to use the data? Do you just want to look at it once in awhile? Do you plan to analyze it in a spreadsheet? Etc. Based upon what you say so far, I would just use a text file, one value per line. Even if later you wanted to do more with it, it's easy to import into spreadsheets, etc. If the daily data is a little more complicated (maybe a couple of different values for things each day), you might consider something like YAML.
Why stray from the path? XML gives you the ability to expand on it later without having to rethink everything.
Its mainly dependent upon the complexity of the data that you want to store. If its just DateTime some other simple built in type you would be able to recreate that object as a strongly typed one easily. But in case if its more complicated I would suggest you to create a serializable class (link on how to create such class is here) and then use one of Binary or SOAP serializations based on the size, security and other such needs. I am suggesting this as it would be best to be able to recreate objects as strongly typed ones from a flat file rather than just trying to parse what's there in the flat file.
Please let me know in case you need more clarity.
Thanks,
Sai Pavan
Can someone please guide me with this problem?
In my institution, we process xml files of huge size(max 1 GB) and insert the details into a database table. Per current design, we are parsing xml file with XmlReader and form a xml string with required data, which will then be passed into a stored procedure (xml data type) to insert the details into db.
Now the problem is we are not sure if there would be a better approach other than this ? so please suggest if are any new features available with .Net 3.5 and/or sql server 2005 to handle this in a way better than our approach.
Any help in this reagrd would be highly appreciated.
Thanks.
Do you care at all what is in the XML-file? If not, you can just use a StreamReader and get the text from the XML and just pass it along to the database.
If you need to validate that the XML is correct, it is a good idea to use XmlReader.
However, just dumping 1GB of XML into your database seems a bit weird, what is the purpose of this XML data? Is it a lot of nested elements? Maybe you could de-serialize it and store each object in the appropriet table instead, which would imo lead to a easier understandable design.
There are a couple of things you can think of to make the design of your software easier/better:
Does more than one XML file occure in the database at once?
How is the data shared between applications?
Have you considered using MemoryMappedFile?
Is it possible to de-serialize the XML into entities instead and store them approprietly?
I suspect that if there are any performance issues it will be with the stored procedure and the database side of things rather that reading the file.
Why are you storing the XML file in a database table? I would suggest using a different solution would be appropriate, but without knowing more details about exactly what it is you are trying to do it is hard to advise.
If each first-level element in the xml is a record, i.e.
<rootNode>
<row>...</row>
<row>...</row>
<row>...</row>
</rootNode>
Then you could create an IDataReader implemention that reads the xml (via XmlReader) and presents each as a record, to be imported using SqlBulkCopy. Pretty much like my old answer here.
Advantages:
SqlBulkCopy is the fastest way to get data into a database
stripping it into records makes appropriate use of a database, allowing indexing and proper typing
it doesn't rely on a huge BLOB going over the wire in an atomic way (necessary for the xml data type)
I am creating an RSS reader as a hobby project, and at the point where the user is adding his own URL's.
I was thinking of two things.
A plaintext file where each url is a single line
SQLite where i can have unique ID's and descriptions following the URL
Is the SQLite idea to much of an overhead or is there a better way to do things like this?
What about as an OPML file? It's XML, so if you needed to store more data then the OPML specification supplies, you can always add your own namespace.
Additionally, importing and exporting from other RSS readers is all done via OPML. Often there is library support for it. If you're interested in having users switch then you have to support OPML. Thansk to jamesh for bringing that point up.
Why not XML?
If you're dealing with RSS anyway you mayaswell :)
Do you plan just to store URLs? Or you plan to add data like last_fetch_time or so?
If it's just a simple URL list that your program will read line-by-line and download data, store it in a file or even better in some serialized object written to a file.
If you plan to extend it, add comments/time of last fetch, etc, I'd go for SQLite, it's not that much overhead.
If it's a single user application that only has one instance, SQLite might be overkill.
You've got a few options as I see it:
SQLite / Database layer. Increases the dependencies your code needs to run. But allows concurrent access
Roll your own text parser. Complexity increases as you want to save more data and you're re-inventing the wheel. Less dependency and initially, while your data is simple, it's trivial for a novice user of your application to edit.
Use XML. It's well formed & defined and text editable. Could be overkill for storing just a URL though.
Use something like pickle to serialize your objects and save them to disk. Changes to your data structure means "upgrading" the pickle files. Not very intuitive to edit for a novice user, but extremely easy to implement.
I'd go with the XML text file option. You can use the XSD tool built into Visual Studio to create a DataTable out of the XML data, and it easily serializes back into the file when needed.
The other caveat is that I'm sure you're going to want the end user to be able to categorize their RSS feeds and be able to potentially search/sort them, and having that kind of datatable style will help with this.
You'll get easy file storage and access, the benefit of a "database" structure, but not quite the overhead of SQLite.