how to lock database from threading system

#include"mutex.h"
#include<time.h>
Mutex::Mutex()
{
 // pthread_mutexattr_init(&attr);
  //pthread_mutexattr_setpshared(&attr,PTHREAD_PROCESS_PRIVAITE);
 // pthread_mutex_init(&lock,NULL);

 lock = PTHREAD_MUTEX_INITIALIZER;
}

void Mutex::Lock()
{
/*struct timespec delta;
delta.tv_sec = 5;
delta.tv_nsec = 0;
pthread_mutex_timedlock_np(&lock,&delta);*/

   pthread_mutex_lock(&lock);

}

void Mutex::Unlock()
{
  pthread_mutex_unlock(&lock);
 pthread_mutex_destroy(&lock);

}
Mutex::~Mutex()
{

}

class LTSC_Manager
{
public:
 LTSC_Manager();
 virtual ~LTSC_Manager();
 
 IDriver * CreateDriver(char * technology);
 int RequestNewIdentifier();
 int DBConnect();  
 CDatabaseModule  dbConnection;
 
 //pthread_mutex_t lock ;
 
 Mutex c_section; // here 

};

   m_Manager->c_section.Lock();
     int res=m_Manager->m_DB.BookFreeTestHead("AXE",&h);
     m_Manager->c_section.Unlock();
printf(" res is %i ",res);