具有某种子方法的C＃创建方法

Question

I want to build my own mysql class. But I'm relative new to c#.

So in my thoughts I would like to build some like:

mySqlTool.select("a,b,c").from("foo").where("x=y");

I dont know how this is called and actually I dont really know if this is even possible. My google search ended with no real result.

So my questions are:

Is it possible to do some like my sample above?

Answer 1

Creating a fluent api isn't overly complicated. You simply return the current instance of the class from each method which allows them to be chained the way that you specify in your post:

public class MySqlTool
{
    private string _fields, _table, _filters;

    public MySqlTool Select(string fields)
    {
        _fields = fields;
        return this;
    }

    public MySqlTool From(string table)
    {
        _table = table;
        return this;
    }

    public MySqlTool Where(string filters)
    {
        _filters = filters;
        return this;
    }

    public Results Execute()
    {
        // build your query from _fields, _table, _filters
        return results;
    }
}

Would allow for you to run a query like:

var tool = new MySqlTool();
var results = tool.Select("a, b, c").From("someTable").Where("a > 1").Execute();

Answer 2

It looks like you are trying to do something similar to Linq to SQL, but with MySQL instead. There is a project called LinqConnect that does this. I have no affiliation with them.

You can use it like this (from a LinqConnect tutorial ):

CrmDemoDataContext context = new CrmDemoDataContext();
var query = from it in context.Companies
    orderby it.CompanyID
    select it;

foreach (Company comp in query)
    Console.WriteLine("{0} | {1} | {2}", comp.CompanyID, comp.CompanyName, comp.Country);

Console.ReadLine();

Answer 3

I'm not a big fan of it personally, but it can be useful if you're just learning. Linq2SQL can give you that functionality somewhat out of the box.

If you're looking to accomplish this yourself. You'll want to turn to extension methods . A feature within c# that will allow you to extend your classes using static methods, operating on the base.

My recommendation if you're doing your own data-access layer, then you should use something like dapper (built/used by the crew at StackOverflow). Which offers you a simple wrapper around the base connection to the database. It offers simple ORM functionality and does parameterization for you.

I would also recommend strongly that you encapsulate your intensive queries within Stored Procedures.

Answer 4

What you're looking to do is design a fluent interface , and it's somewhat of an advanced concept for someone who is just learning C#. I would suggest you stick to the basics until you have a little more experience.

More importantly, there are already existing data adapters built into the .NET FCL and also third-party adapters like this one that are more suitable and already do what you're trying to do using "LINQ to (database)". I wouldn't reinvent the wheel if I were you.