How to implement database connection pooling in unigui?

[ChenHaibin]

How to implement database connection pooling in unigui?

[jlrozano]

I think you can use a static class as

 

 

TConnectionPool = class

private

class var FConnectionList: TThreadList;

class procedure CloseAll;

public

class function Get: TConnection;

class procedure Release( cn: TConnection);

end

 

.....

 

function TConnectionPoll.Get;

var

LList: TList;

begin

LList := FConnectionList.LockList;

try

if LList.Count = 0 then

Result := TConnection.Create(....)

else

begin

Result := TConnection(LList[0]);

LList.Delete(0);

end

finally

FConnectionList.UnLockList;

end;

end;

 

 

procedure TConnectionPool.CloseAll;

var

LList: TList;

LIndex: integer;

begin

try

for LIndex := 0 to LList.Count-1 do

TConnection(LLIst.Free);

LList.Clear;

finally

FConnectionList.UnLockList;

end;

end;

 

procedure TConnectionPool.Release(cn: TConnection);

var

LList: TList;

begin

LList := FConnectionList.LockList;

try

if LList.Count< MaxPoolSize then

LList.Add(cn)

else

cn.Free;

finally

FConnectionList.UnLockList;

end;

end;

 

....

 

initialization

TConnectionPool.FConnectionList := TThreadList.Create;

finalization

TConnectionPool.CloseAll;

TConnectionPool.FConnectionList.Free;

End..

 

( code is not real, only as example idea).

 

Use:

 

....

var

LCn: TConnection;

begin

....

LCn := TConnectionPool.Get;

try

<your code>

finally

TConnectionPool.Release(cn);

end;

.....

[ChenHaibin]

Thank you! Very nice idea！

In application, I think the object should be created in ServerModule.....Right?

If someone can make a example, it would be better.

[jlrozano]

Thank you! Very nice idea！

In application, I think the object should be created in ServerModule.....Right?

If someone can make a example, it would be better.

 

 

This class can be defined into a new unit. When you need a connection, use it. It is a static class, so it is shared by all sessions. Only use as example:

 

var

LCn: TConnection;

begin

....

LCn := TConnectionPool.Get;

try

<your code>

finally

TConnectionPool.Release(cn);

end;