One connection with DB or many?

[elGringo]

I use firedac but for my question it doesn't matter.

 

What is better?

 

To use 1 connection with DB or Many?

 

1 connection is like

 In mainUnit I create FDConnection:TFDConnection and everywhere in other modules I will use link to that

 

Many Connections means

 For Every procedure of every module I will Create Connection like

   procedure MyProcInSomeModule;
   var FDConnectionLocal:TFDConnection;
   begin
   
   FDConnectionLocal:=TFDConnection.Create(Self);
  
   //Do something;

   FreeAndNil(FDConnectionLocal);
   
   end;

Sometimes in MYSQL i meet "Too many connections" that's why I ask.

 

What is your experience. What is normal practice???

 

[adragan]

In MainModule you create a connection. All DB objects from other forms and frames link to that connection.

It's more economic in terms of database connections.

[elGringo]

Yes, but second approach calls connection only in the moment program need.

[albertovesx]

Yes, but second approach calls connection only in the moment program need.

It could be a slow method

[zilav]

The better is multiple connections with pooling. I don't use FireDAC and don't have any idea about it's support for pooling. In the worst case you can write your own connections pool.

 

Edit: a quick google attempt shows http://docwiki.embarcadero.com/CodeExamples/Berlin/en/FireDAC.Pooling_Sample

[elGringo]

Thank you, Zilav. 

multiple connections with pooling ? How much multuple? One for the unit, one for the procedure,function, one for the program?))

About pooling - yes - very useful information - i've read it monthes ago but have forgotten for the moment.

 

Now - i'm rewriting app to have one connection for the thread. One Connection for the main thread and others for each thread created in program. As I understand docs - it is correct;

[zilav]

Usually the size of pool is set to an average expected number of clients to work at the same time. However pools are dynamic and will expand if more connections are required. Check FireDAC docs.