C ++静态变量可由类成员访问

Question

Please have a look at the following code:

#include<string>
class abc
{
  public:
    static const abc PENDING;
  private:
    static const string PENDING_STATUS_CD;
    abc ( const string& iStatus )
    {
     //...........
     Logintodatabase();
     //.............
     logoutfromdatabase();

    }
};

const string abc::PENDING_STATUS_CD  = "P";
const abc abc::PENDING ( abc::PENDING_STATUS_CD );

---

Once the const abc abc::PENDING( abc::PENDING_STATUS_CD ); is called, it will call constructor abc ( const string& iStatus ) .

In fact if more than one static class variable is defined inside class, for each initialization it will call the constructor.

This constructor is responsible for opening & closing the database.
For each static variable initialization, the database will open & close.
Suppose this class is used by more than one process then so many times database will open & close.

can you suggest how to overcome this issue?

can anyone tell me how to design this logic?

Answer 1

The database is a dependency. Pass it from outside, maybe in the constructor. Assume it already is open and let the caller of your class worry about opening, closing or caching connections.

On a technical level, if you don't want to do dependency injection, look up connection pooling for your respective database.