C# – How to Save Complex Data to File or Disk

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I am working on a side project for a small business owner (my father) and part of the requirements for the application include saving customer and job related data in a way that it can easily be backed up and/or restored on demand.

I am familiar with how to save data to a flat file, and I am familiar with how to save data to a database. What I feel like I am missing is what are "typical" strategies for saving data such as I described above to a file?

For example I noticed Quickbooks has their own file format that encapsulates an entire "business" in one file that can easily be backed up and/or used for restoration. (Briefly) How is that accomplished?

I have come across integrated databases such as sqlExpress and am left wondering if this is how end user applications typically manage data or if it is something else entirely.

In short, how can I encapsulate a large amount of complex data into a single file either of a simple data type (i.e. .DAT/.TXT) or possibly a custom file format?

EDIT: As an added bit of information I would like to avoid having to install a stand-alone RDBMS in order to save data to a database.

Best Answer

Building on Franck's comment, you can use a DataSet to save to XML.

Writing DataSet Contents as XML Data

System.IO.StreamWriter xmlSW = new System.IO.StreamWriter("Customers.xml");

// This example assumes you have a custom dataset called ds holding customer data
ds.WriteXml(xmlSW, XmlWriteMode.WriteSchema);

xmlSW.Close();

This will produce an XML file called Customers.xml in your current directory that is a serialized version of your DataSet.

You will also need to know how to load that data back into your objects... Loading a DataSet from XML

// Load the dataset from a file called input.xml
DataSet ds = new DataSet();
ds.ReadXml("Customers.xml", XmlReadMode.ReadSchema);

Related Solutions

Data structure for file search

An Inverted Index seems to be what you seek. The basic idea is:

The messages/files are saved on disk in their full structure.
Each word in the file has a row in a table in the database.
There's a link table that allows you to do a join between the words and a unique ID for each message/file.

For example, here's the 3 database tables as I would create:

CREATE TABLE words (
    word_id INT PRIMARY KEY,
    word TEXT
)
CREATE TABLE links (
    word_id INT FOREIGN KEY words(word_id),
    file_id INT FOREIGN KEY files(file_id),
)
CREATE TABLE files (
    file_id INT PRIMARY KEY,
    filename TEXT
)

To find all filenames that contain the words "help" and "me":

SELECT filename
FROM files
INNER JOIN links l1 ON (files.file_id = l1.file_id)
INNER JOIN words w1 ON (l1.word_id = w1.word_id)
INNER JOIN links l2 ON (files.file_id = l2.file_id)
INNER JOIN words w2 ON (l2.word_id = w2.word_id)
WHERE w1.word = "help" AND w2.word = "me"

That help?

Haskell Data Structures – Is It Safe to Save and Retrieve Using Show and Read

It's perfectly safe to do it this way, especially since, as Doval pointed out, all the instances of Show and Read that you're using are in the standard library, and are thus guaranteed to cooperate with each other without any difficulty.

However, it's not the generally recommended way to do it, simply because saving to human-readable (and Haskell-readable) text is nowhere near as efficient as a tag-based binary format. For this, you can use the binary package, which already includes instances for all of the datatypes that you're using in the question.

More to the point, though, using the binary package to serialize to and deserialize from disk is even easier then using Show and Read! (Just use the functions encodeFile and decodeFile(OrFail) from the Data.Binary module.) In general, you will have to get used to things in Haskell being much simpler, at least in the common cases, then they typically are in most imperative languages. :)

Best Answer

Related Solutions

Data structure for file search

Haskell Data Structures – Is It Safe to Save and Retrieve Using Show and Read

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