Scott Hanselman

KISS - Keep it Simple, Stupid. While I don't like calling people stupid, I do like to Keep it Super Simple!

I was talking to Jeff Fritz on my team about a new system we're architecting. I suggested CosmosDB or perhaps Azure Table Storage. Then we considered the amount of data we were storing (less than 100 megs) and Jeff said...let's just use CSV files and CsvHelper.

First I was shocked. SHOCKED I SAY.

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Then I was offended

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But finally I was hey...that's a good idea.

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A fine idea in fact. Why use more moving parts than needed? Sure we could use XML or JSON, but for our project we decided rather than even bother with an admin site that we'd use Excel for administration! It edits CSV files nicely thank you very much.

Can you parse CSV files yourself? Sure, but it'll start getting complex as you move between data types, think about quotes, deal with headers, whitespace, encoding, dates, etc. CSV files can be MUCH more complex and subtle than you'd think. Really.

Here's what CsvHelper can do for you:

var csv = new CsvReader( textReader );
var records = csv.GetRecords<MyClass>();

Here you just get an array of some class - if your class's structure maps 1:1 with your CSV file. If not, you can map your class with a projection of the types in the CSV file.

public sealed class PersonMap : CsvClassMap<Person>
{
    public PersonMap()
    {
        Map( m => m.Id );
        Map( m => m.Name );
        References<AddressMap>( m => m.Address );
    }
}

public sealed class AddressMap : CsvClassMap<Address>
{
    public AddressMap()
    {
        Map( m => m.Street );
        Map( m => m.City );
        Map( m => m.State );
        Map( m => m.Zip );
    }
}

And finally, just want to export a CSV from an Enumerable that mirrors what you want? Boom.

var csv = new CsvWriter( textWriter );
csv.WriteRecords( records );

Or do it manually if you like (hardcode some, pull from multiple sources, whatever):

var csv = new CsvWriter( textWriter );
foreach( var item in list )
{
    csv.WriteField( "a" );
    csv.WriteField( 2 );
    csv.WriteField( true );
    csv.NextRecord();
}

It won't replace SQL Server but it may just replace one-table SQLite's and "using a JSON file as a database" for some of your smaller projects. Check out CsvHelper's site and excellent docs here along with the CsvHelper GitHub here.

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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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