Data Access Layer - Designing Class where should responsibility of creating saving be

Question

I am designing Data Access Layer with ADO.NET 2.0 and C#, Sql Server 2005. I often fight with my brain over where to place those calls. Which way of the below i should follow for maintainable robust code.

Method 1

Public Class Company
{

public string CompanyId
{get;set;}

public string CompanyAddress
{get;set;}

public bool Create()
{
}

public bool Update()
{
}

public bool Delete()
{
}

}

Method 2

Public Class Company
{

public string CompanyId
{get;set;}

public string CompanyAddress
{get;set;}
}

and i would use another class like below to do the core data access. Like below

Public Class CompanyRepository
{

public Company CreateCompany(string companyId,string companyDescription)
{
}

public bool UpdateCompany(Company updateCompany)
{
}

public bool DeleteCompany(string companyId)
{
}

public List<Company> FindById(string id)
{
}


}

Answer 1

Go with method 2. It is not the Company class's responsibility to read/write from a data source (single responsibility principle). However, I would even go as far as creating an ICompanyRepository interface and then creating a CompanyRepository implementation for the interface. This way you can inject the ICompanyRepository into the class that needs to save/retrieve company information. It also allows easier unit testing and the ability to create a different implementation in the future (switching from a database to xml files or whatever).