TDbiConnection.hxx

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#ifndef DBICONNECTION
#define DBICONNECTION


//////////////////////////////////////////////////////////////////////////
////////////////////////////     ROOT API     ////////////////////////////
//////////////////////////////////////////////////////////////////////////

/**
 *
 *
 * \class TDbiConnection
 *
 *
 * \brief
 * <b>Concept</b> A managed TSQLServer connection- dropped when idle.
 *
 * \brief
 * <b>Purpose</b> To minimise connections.
 *
 * Contact: A.Finch@lancaster.ac.uk
 *
 *
 */


#include <string>

#ifndef ROOT_Rtypes
#if !defined(__CINT__) || defined(__MAKECINT__)
#include "Rtypes.h"
#endif
#endif
#include "TSQLServer.h"
#include "TSQLStatement.h"
#include "TUrl.h"

#include "TDbi.hxx"
#include "TDbiExceptionLog.hxx"

class TDbiConnection
{

public:

// Constructors and destructors.
/// 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(const std::string& url = "",
                         const std::string& user = "",
                         const std::string& password = "",
                         int maxConnects=20);
  virtual ~TDbiConnection();

// State testing member functions

// Standard getters.

    const std::string& GetDbName() const { return fDbName; }
    const std::string& GetPassword() const { return fPassword; }
    const std::string& GetUrl() const;
    const std::string& GetUser() const { return fUser; }
                Bool_t IsClosed() const { return ! fServer; }
                Bool_t IsTemporary() const { return fIsTemporary; }
                Bool_t TableExists(const std::string& tableName) const;

// Exception log handling

  const TDbiExceptionLog& GetExceptionLog() const { return fExceptionLog; }
  void ClearExceptionLog() { fExceptionLog.Clear(); }

/// Print exceptions at level of above and return true if any
  Bool_t PrintExceptionLog(Int_t level = 3) const;

  void RecordException();

// State changing member functions

/// Add name to list of existing tables (necessary when creating tables)
/// Default name = "", reread all tables from database.
  void SetTableExists(const std::string& tableName = "");

// Idle connnection management

/// Methods used when "borrowing" the server (use same as for Statement).
  void Connect()    { this->ConnectStatement(); }
  void DisConnect() { this->DisConnectStatement(); }

/// Increment number of statements relying on this connection
  void ConnectStatement() { ++fNumConnectedStatements; }
/// Decrement number of statements relying on this connection and close if idle
  void DisConnectStatement() {
       --fNumConnectedStatements;
      if ( ! fNumConnectedStatements ) this->CloseIdleConnection(); }
/// Connection is permanent, don't close even when idle.
  void SetPermanent(Bool_t permanent = true) { fIsTemporary = ! permanent; }


  Bool_t Close(Bool_t force = false);
  Bool_t Open();

/// Get server, opening if necessary
/// TDbiConnection retains ownership
  TSQLServer* GetServer();

/// Get statement, opening if necessary.
/// Caller must take ownership.
  TSQLStatement* CreatePreparedStatement(const std::string& sql);

private:

  void CloseIdleConnection();


// Data members

/// Database Name.
  std::string fDbName;

///  A comma separate list of existing tables each in single quotes : 'table1','table2',...
    std::string fExistingTableList;

/// TSQLServer URL
  TUrl fUrl;

/// Username
  std::string fUser;

/// Password
  std::string fPassword;

/// True if URL works
  Bool_t fUrlValidated;

  /// Maximum number of times to try making a connection.
      int fMaxConnectionAttempts;

/// Number of connected statements
  Int_t fNumConnectedStatements;

/// Connection closes after each I/O (no connections left)
  Bool_t fIsTemporary;

/// TSQLServer or 0 if closed
  TSQLServer* fServer;

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

 ClassDef(TDbiConnection,0)     // Managed TSQLServer

};


#endif // DBICONNECTION