TDbiConnection Class Reference

Concept A managed TSQLServer connection- dropped when idle. More...

#include <TDbiConnection.hxx>

Collaboration diagram for TDbiConnection:

[legend]

List of all members.

Public Member Functions
	TDbiConnection (const std::string &url="", const std::string &user="", const std::string &password="", int maxConnects=20)
virtual	~TDbiConnection ()
const std::string &	GetDbName () const
const std::string &	GetPassword () const
const std::string &	GetUrl () const
const std::string &	GetUser () const
Bool_t	IsClosed () const
Bool_t	IsTemporary () const
Bool_t	TableExists (const std::string &tableName) const
const TDbiExceptionLog &	GetExceptionLog () const
void	ClearExceptionLog ()
Bool_t	PrintExceptionLog (Int_t level=3) const
	Print exceptions at level of above and return true if any.
void	RecordException ()
void	SetTableExists (const std::string &tableName="")
void	Connect ()
	Methods used when "borrowing" the server (use same as for Statement).
void	DisConnect ()
void	ConnectStatement ()
	Increment number of statements relying on this connection.
void	DisConnectStatement ()
	Decrement number of statements relying on this connection and close if idle.
void	SetPermanent (Bool_t permanent=true)
	Connection is permanent, don't close even when idle.
Bool_t	Close (Bool_t force=false)
Bool_t	Open ()
TSQLServer *	GetServer ()
TSQLStatement *	CreatePreparedStatement (const std::string &sql)
Private Member Functions
void	CloseIdleConnection ()
Private Attributes
std::string	fDbName
	Database Name.
std::string	fExistingTableList
	A comma separate list of existing tables each in single quotes : 'table1','table2',...
TUrl	fUrl
	TSQLServer URL.
std::string	fUser
	Username.
std::string	fPassword
	Password.
Bool_t	fUrlValidated
	True if URL works.
int	fMaxConnectionAttempts
	Maximum number of times to try making a connection.
Int_t	fNumConnectedStatements
	Number of connected statements.
Bool_t	fIsTemporary
	Connection closes after each I/O (no connections left).
TSQLServer *	fServer
	TSQLServer or 0 if closed.
TDbiExceptionLog	fExceptionLog

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Detailed Description

Concept A managed TSQLServer connection- dropped when idle.

Purpose To minimise connections. Contact: A.Finch@lancaster.ac.uk

Definition at line 42 of file TDbiConnection.hxx.

---

Constructor & Destructor Documentation

TDbiConnection::TDbiConnection	(	const std::string &	url = "",
		const std::string &	user = "",
		const std::string &	password = "",
		int	maxConnects = 20
	)

Passed in url - address of sql server user - username to use password - password to use macConnects = maximum number of connections to attempt before giving up, default to 20 throws EBadConnection() if can not make connection

TDbiConnection::~TDbiConnection

(

)

[virtual]

Definition at line 117 of file TDbiConnection.cxx.

References Close(), and SK_DBI_Trace.

                                {
//
//
//  Purpose: Destructor


  SK_DBI_Trace( "Destroying TDbiConnection" << "  ");
  this->Close(true);

}

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Member Function Documentation

void TDbiConnection::ClearExceptionLog

(

)

[inline]

Definition at line 76 of file TDbiConnection.hxx.

References TDbiExceptionLog::Clear(), and fExceptionLog.

Referenced by Close(), and Open().

{ fExceptionLog.Clear(); }

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Bool_t TDbiConnection::Close

(

Bool_t

force = false

)

   
     Purpose: Close server connection unless active (or always if forced) .
   
     Return:  true if connection now closed.
   

Definition at line 134 of file TDbiConnection.cxx.

References ClearExceptionLog(), fNumConnectedStatements, fServer, GetUrl(), IsClosed(), SK_DBI_Debug, and SK_DBI_Info.

Referenced by CloseIdleConnection(), and ~TDbiConnection().

                                                        {

  this->ClearExceptionLog();
  if ( this->IsClosed() ) return true;

  if ( fNumConnectedStatements ) {
    if ( ! force ) {
      SK_DBI_Info( "Unable to close connection: " << this->GetUrl()
                            << "; it still has  "
                            << fNumConnectedStatements << "active statements. " << "  ");
      return false;
    }
    SK_DBI_Info( "Closing connection: " << this->GetUrl()
                          << "; even though it still has "
                          << fNumConnectedStatements << " active statements. " << "  ");
  }

  delete fServer;
  fServer = 0;
  SK_DBI_Debug( "Closed connection: " << this->GetUrl() << "  ");
  return true;

}

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void TDbiConnection::CloseIdleConnection

(

)

[private]

Purpose: Close idle connection. Idle means there are no active connections to this database.

Definition at line 163 of file TDbiConnection.cxx.

References Close(), fIsTemporary, and fNumConnectedStatements.

Referenced by DisConnectStatement().

                                         {

  if ( fIsTemporary &&  fNumConnectedStatements == 0 ) this->Close();

}

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void TDbiConnection::Connect

(

)

[inline]

Methods used when "borrowing" the server (use same as for Statement).

Definition at line 92 of file TDbiConnection.hxx.

References ConnectStatement().

Referenced by Open(), and TDbiDBProxy::StoreMetaData().

{ this->ConnectStatement(); }

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void TDbiConnection::ConnectStatement

(

)

[inline]

Increment number of statements relying on this connection.

Definition at line 96 of file TDbiConnection.hxx.

References fNumConnectedStatements.

Referenced by Connect().

{ ++fNumConnectedStatements; }

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TSQLStatement * TDbiConnection::CreatePreparedStatement

(

const std::string &

sql

)

Get statement, opening if necessary. Caller must take ownership.

   
     Purpose:  Open if necessary and get a prepared statment.
   
     Return:    Statement - Caller must take ownership.
                will be 0 if failure.
   

Definition at line 178 of file TDbiConnection.cxx.

References TDbiExceptionLog::AddEntry(), fExceptionLog, fServer, and Open().

Referenced by TDbiStatement::CreateProcessedStatement().

                                                                           {

  TSQLStatement* stmt = 0;
  if ( ! this->Open() ) return stmt;
  stmt = fServer->Statement(sql.c_str());
  if ( ! stmt ) {
    fExceptionLog.AddEntry(*fServer);
  }
  else stmt->EnableErrorOutput(false);

  return stmt;
}

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void TDbiConnection::DisConnect

(

)

[inline]

Definition at line 93 of file TDbiConnection.hxx.

References DisConnectStatement().

Referenced by TDbiDBProxy::StoreMetaData().

{ this->DisConnectStatement(); }

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void TDbiConnection::DisConnectStatement

(

)

[inline]

Decrement number of statements relying on this connection and close if idle.

Definition at line 98 of file TDbiConnection.hxx.

References CloseIdleConnection(), and fNumConnectedStatements.

Referenced by DisConnect(), and TDbiStatement::~TDbiStatement().

                             {
       --fNumConnectedStatements;
      if ( ! fNumConnectedStatements ) this->CloseIdleConnection(); }

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const std::string& TDbiConnection::GetDbName

(

)

const [inline]

Definition at line 65 of file TDbiConnection.hxx.

References fDbName.

Referenced by TDbiStatement::ExecuteQuery(), and TDbiStatement::ExecuteUpdate().

{ return fDbName; }

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const TDbiExceptionLog& TDbiConnection::GetExceptionLog

(

)

const [inline]

Definition at line 75 of file TDbiConnection.hxx.

References fExceptionLog.

Referenced by TDbiStatement::AppendExceptionLog().

{ return fExceptionLog; }

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const std::string& TDbiConnection::GetPassword

(

)

const [inline]

Definition at line 66 of file TDbiConnection.hxx.

References fPassword.

{ return fPassword; }

TSQLServer * TDbiConnection::GetServer

(

)

Get server, opening if necessary TDbiConnection retains ownership

   
     Purpose:  Open if necessary and get a TSQLServer.
   
     Return:    Server ( = 0 if connection not open).
   
     WARNING:  The server returned remains is being borrowed from the
               TDbiConnection and remains under its ownership and must
               not be deleted.  However the caller must invoke the
               Connect() method on this TDbiConnection before borrowing
               it and must invoke the DisConnect() when it has finished
               using it to ensure the TDbiConnection does not close it
               prematurely i.e.:-
   
               void Demo(TDbiConnection* con) {
                 con->Connect();
                 TSQLServer* server = con->GetServer();
                 // Do stuff
                 con->DisConnect();
               }
   

Definition at line 212 of file TDbiConnection.cxx.

References fServer, and Open().

Referenced by TDbiStatement::ExecuteUpdate(), and TDbiDBProxy::StoreMetaData().

                                      {


  if ( ! this->Open() ) return 0;
  return fServer;
}

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const std::string & TDbiConnection::GetUrl

(

)

const

    Don't ask me why TUrl::GetUrl() is non-const, just accept that it is!
   
    Note: This function returns a reference to a shared string; use the
          value or make a copy of it before any subsequent call to this
          function.
   

Definition at line 227 of file TDbiConnection.cxx.

References fUrl.

Referenced by Close(), and TDbiCascader::CreateTemporaryTable().

                                              {

  

  static std::string url;
  url = const_cast<TDbiConnection*>(this)->fUrl.GetUrl();
  return url;

}

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const std::string& TDbiConnection::GetUser

(

)

const [inline]

Definition at line 68 of file TDbiConnection.hxx.

References fUser.

{ return fUser; }

Bool_t TDbiConnection::IsClosed

(

)

const [inline]

Definition at line 69 of file TDbiConnection.hxx.

References fServer.

Referenced by Close(), and Open().

{ return ! fServer; }

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Bool_t TDbiConnection::IsTemporary

(

)

const [inline]

Definition at line 70 of file TDbiConnection.hxx.

References fIsTemporary.

Referenced by TDbiCascader::CreateTemporaryTable().

{ return fIsTemporary; }

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Bool_t TDbiConnection::Open

(

)

Purpose: Open connection if necessary.

Definition at line 242 of file TDbiConnection.cxx.

References TDbiExceptionLog::AddEntry(), TDbiServices::AsciiDBConectionsTemporary(), ClearExceptionLog(), Connect(), fExceptionLog, fIsTemporary, fMaxConnectionAttempts, fPassword, fServer, fUrl, fUrlValidated, fUser, TDbiAsciiDbImporter::GetExceptionLog(), TDbiAsciiDbImporter::GetImportedTableNames(), IsClosed(), SetTableExists(), SK_DBI_Debug, SK_DBI_Log, SK_DBI_Severe, and SK_DBI_Warn.

Referenced by ClassImp(), CreatePreparedStatement(), and GetServer().

                            {


  this->ClearExceptionLog();
  if ( ! this->IsClosed() ) return true;

  if ( ! fUrl.IsValid() ) {

    ostringstream oss;
    oss << "Unable to open connection: URL '" << fUrl.GetUrl() << "' is invalid";
       SK_DBI_Severe( oss.str() << "  ");
    fExceptionLog.AddEntry(oss.str());
    return false;
  }

  // Make several attempts (or more if URL is known to be O.K.) to open connection.
  int maxAttempt = fUrlValidated ?  100: fMaxConnectionAttempts ;
  for (int attempt = 1; attempt <= maxAttempt; attempt++) {
    fServer = TSQLServer::Connect(fUrl.GetUrl(),fUser.c_str(),fPassword.c_str());

    if ( ! fServer ) {
      ostringstream oss;
      oss << "Failing to open: " << fUrl.GetUrl() << " for user " << fUser
          << " and password " << fPassword << " (attempt " << attempt << ")";
      fExceptionLog.AddEntry(oss.str());
      if ( fMaxConnectionAttempts > attempt ){
         
         if ( attempt == 1 ) {
              SK_DBI_Severe( " retrying ... " << "  ");
         }
         SK_DBI_Log(" Waiting "<<attempt<<" seconds before trying again");
         gSystem->Sleep(attempt*1000);
      }
    }

    else {
      fServer->EnableErrorOutput(false);
      if ( attempt > 1 ) SK_DBI_Warn( "... Connection opened on attempt " << attempt << "  ");
      SK_DBI_Debug(  "Successfully opened connection to: " << fUrl.GetUrl() << "  ");

      // If this is an ASCII database, populate it and make the connection permanent
      // unless even ASCII DB connections are temporary.

      TString ascii_file = fUrl.GetAnchor();
      if ( ascii_file.IsNull() ) return true;
      gSystem->Setenv("DBI_CATALOGUE_PATH",gSystem->DirName(fUrl.GetAnchor()));
      TDbiAsciiDbImporter importer(ascii_file,fServer);
      const TDbiExceptionLog& el(importer.GetExceptionLog());
      if ( ! el.IsEmpty() ) {
        SK_DBI_Severe( "Failed to populate ASCII database from " << fUrl.GetUrl() << "\n"
                               << el << "  ");
        delete fServer;
        fServer = 0;
        return false;
      }
      fIsTemporary = TDbiServices::AsciiDBConectionsTemporary();
      // Add imported tables names.
      const std::list<std::string> tableNames(importer.GetImportedTableNames());
      std::list<std::string>::const_iterator itr(tableNames.begin()), itrEnd(tableNames.end());
      while ( itr != itrEnd ) {
        this->SetTableExists(*itr);
        ++itr;
      }
      return true;

    }
  }
     SK_DBI_Severe(  "... Failed to open a connection to: " << fUrl.GetUrl()
    << " for user " << fUser << " and pwd " << fPassword << "  ");

  return false;

}//

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Bool_t TDbiConnection::PrintExceptionLog

(

Int_t

level = 3

)

const

Print exceptions at level of above and return true if any.

   
     Purpose:  Print all warning at supplied  Msg log level.
   
     Return:    kTRUE if warnings have occurred
   

Definition at line 325 of file TDbiConnection.cxx.

References fExceptionLog, and TDbiExceptionLog::Size().

                                                          {


  return fExceptionLog.Size() != 0;

}

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void TDbiConnection::RecordException

(

)

Purpose: Record an exception that has occurred while a client was using its TSQLServer.

Definition at line 336 of file TDbiConnection.cxx.

References TDbiExceptionLog::AddEntry(), fExceptionLog, and fServer.

Referenced by TDbiStatement::ExecuteUpdate().

                                      {

  fExceptionLog.AddEntry(*fServer);

}

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void TDbiConnection::SetPermanent

(

Bool_t

permanent = true

)

[inline]

Connection is permanent, don't close even when idle.

Definition at line 102 of file TDbiConnection.hxx.

References fIsTemporary.

Referenced by TDbiCascader::CreateTemporaryTable().

{ fIsTemporary = ! permanent; }

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void TDbiConnection::SetTableExists

(

const std::string &

tableName = ""

)

Add name to list of existing tables (necessary when creating tables) Default name = "", reread all tables from database.

Referenced by TDbiCascader::CreateTemporaryTable(), and Open().

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Bool_t TDbiConnection::TableExists

(

const std::string &

tableName

)

const

Referenced by TDbiCascader::GetTableDbNo().

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Member Data Documentation

std::string TDbiConnection::fDbName [private]

Database Name.

Definition at line 124 of file TDbiConnection.hxx.

Referenced by GetDbName().

TDbiExceptionLog TDbiConnection::fExceptionLog [private]

Log of exceptions generated. Cleared by Open Close and (implicitly) by CreatePreparedStatement, GetServer

Definition at line 155 of file TDbiConnection.hxx.

Referenced by ClearExceptionLog(), CreatePreparedStatement(), GetExceptionLog(), Open(), PrintExceptionLog(), and RecordException().

std::string TDbiConnection::fExistingTableList [private]

A comma separate list of existing tables each in single quotes : 'table1','table2',...

Definition at line 127 of file TDbiConnection.hxx.

Bool_t TDbiConnection::fIsTemporary [private]

Connection closes after each I/O (no connections left).

Definition at line 148 of file TDbiConnection.hxx.

Referenced by CloseIdleConnection(), IsTemporary(), Open(), and SetPermanent().

int TDbiConnection::fMaxConnectionAttempts [private]

Maximum number of times to try making a connection.

Definition at line 142 of file TDbiConnection.hxx.

Referenced by Open().

Int_t TDbiConnection::fNumConnectedStatements [private]

Number of connected statements.

Definition at line 145 of file TDbiConnection.hxx.

Referenced by Close(), CloseIdleConnection(), ConnectStatement(), and DisConnectStatement().

std::string TDbiConnection::fPassword [private]

Password.

Definition at line 136 of file TDbiConnection.hxx.

Referenced by GetPassword(), and Open().

TSQLServer* TDbiConnection::fServer [private]

TSQLServer or 0 if closed.

Definition at line 151 of file TDbiConnection.hxx.

Referenced by Close(), CreatePreparedStatement(), GetServer(), IsClosed(), Open(), and RecordException().

TUrl TDbiConnection::fUrl [private]

TSQLServer URL.

Definition at line 130 of file TDbiConnection.hxx.

Referenced by GetUrl(), and Open().

Bool_t TDbiConnection::fUrlValidated [private]

True if URL works.

Definition at line 139 of file TDbiConnection.hxx.

Referenced by Open().

std::string TDbiConnection::fUser [private]

Username.

Definition at line 133 of file TDbiConnection.hxx.

Referenced by GetUser(), and Open().

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The documentation for this class was generated from the following files:

• src/TDbiConnection.hxx
• src/TDbiConnection.cxx