libpqxx  4.0.1
pqxx::transaction< ISOLATIONLEVEL, READWRITE > Class Template Reference

Standard back-end transaction, templatized on isolation level. More...

#include <transaction.hxx>

Inheritance diagram for pqxx::transaction< ISOLATIONLEVEL, READWRITE >:
pqxx::basic_transaction pqxx::dbtransaction pqxx::transaction_base pqxx::internal::namedclass

Public Types

typedef isolation_traits< ISOLATIONLEVEL > isolation_tag
 
- Public Types inherited from pqxx::transaction_base
typedef isolation_traits< read_committedisolation_tag
 If nothing else is known, our isolation level is at least read_committed. More...
 

Public Member Functions

 transaction (connection_base &C, const std::string &TName)
 Create a transaction. More...
 
 transaction (connection_base &C)
 
virtual ~transaction () throw ()
 
- Public Member Functions inherited from pqxx::dbtransaction
virtual ~dbtransaction ()
 
- Public Member Functions inherited from pqxx::transaction_base
virtual ~transaction_base ()=0
 
void commit ()
 Commit the transaction. More...
 
void abort ()
 Abort the transaction. More...
 
std::string esc (const char str[]) const
 Escape string for use as SQL string literal in this transaction. More...
 
std::string esc (const char str[], size_t maxlen) const
 Escape string for use as SQL string literal in this transaction. More...
 
std::string esc (const std::string &str) const
 Escape string for use as SQL string literal in this transaction. More...
 
std::string esc_raw (const unsigned char str[], size_t len) const
 Escape binary data for use as SQL string literal in this transaction. More...
 
std::string esc_raw (const std::string &) const
 Escape binary data for use as SQL string literal in this transaction. More...
 
template<typename T >
std::string quote (const T &t) const
 Represent object as SQL string, including quoting & escaping. More...
 
std::string quote_raw (const unsigned char str[], size_t len) const
 Binary-escape and quote a binarystring for use as an SQL constant. More...
 
std::string quote_raw (const std::string &str) const
 
std::string quote_name (const std::string &identifier) const
 Escape an SQL identifier for use in a query. More...
 
result exec (const std::string &Query, const std::string &Desc=std::string())
 Execute query. More...
 
result exec (const std::stringstream &Query, const std::string &Desc=std::string())
 
internal::parameterized_invocation parameterized (const std::string &query)
 Parameterize a statement. More...
 
connection_baseconn () const
 Connection this transaction is running in. More...
 
void set_variable (const std::string &Var, const std::string &Val)
 Set session variable in this connection. More...
 
std::string get_variable (const std::string &)
 Get currently applicable value of variable. More...
 
prepare::invocation prepared (const std::string &statement=std::string())
 Execute prepared statement. More...
 
void process_notice (const char Msg[]) const
 Have connection process warning message. More...
 
void process_notice (const std::string &Msg) const
 Have connection process warning message. More...
 
- Public Member Functions inherited from pqxx::internal::namedclass
 namedclass (const std::string &Classname, const std::string &Name="")
 
const std::string & name () const throw ()
 
const std::string & classname () const throw ()
 
std::string description () const
 

Additional Inherited Members

- Protected Member Functions inherited from pqxx::basic_transaction
 basic_transaction (connection_base &C, const std::string &IsolationLevel, readwrite_policy)
 
- Protected Member Functions inherited from pqxx::dbtransaction
 dbtransaction (connection_base &, const std::string &IsolationString, readwrite_policy rw=read_write)
 
 dbtransaction (connection_base &, bool direct=true, readwrite_policy rw=read_write)
 
void start_backend_transaction ()
 Start a transaction on the backend and set desired isolation level. More...
 
virtual void do_begin ()
 Sensible default implemented here: begin backend transaction. More...
 
virtual result do_exec (const char Query[])
 Sensible default implemented here: perform query. More...
 
virtual void do_abort ()
 Sensible default implemented here: abort backend transaction. More...
 
- Protected Member Functions inherited from pqxx::transaction_base
 transaction_base (connection_base &c, bool direct=true)
 Create a transaction (to be called by implementation classes only) More...
 
void Begin ()
 Begin transaction (to be called by implementing class) More...
 
void End () throw ()
 End transaction. To be called by implementing class' destructor. More...
 
result DirectExec (const char C[], int Retries=0)
 Execute query on connection directly. More...
 
void reactivation_avoidance_clear () throw ()
 Forget about any reactivation-blocking resources we tried to allocate. More...
 
- Static Protected Member Functions inherited from pqxx::dbtransaction
static std::string fullname (const std::string &ttype, const std::string &isolation)
 
- Protected Attributes inherited from pqxx::transaction_base
internal::reactivation_avoidance_counter m_reactivation_avoidance
 Resources allocated in this transaction that make reactivation impossible. More...
 

Detailed Description

template<isolation_level ISOLATIONLEVEL = read_committed, readwrite_policy READWRITE = read_write>
class pqxx::transaction< ISOLATIONLEVEL, READWRITE >

Standard back-end transaction, templatized on isolation level.

This is the type you'll normally want to use to represent a transaction on the database.

While you may choose to create your own transaction object to interface to the database backend, it is recommended that you wrap your transaction code into a transactor code instead and let the transaction be created for you.

See also
pqxx/transactor.hxx

If you should find that using a transactor makes your code less portable or too complex, go ahead, create your own transaction anyway.

Usage example: double all wages

extern connection C;
work T(C);
try
{
T.exec("UPDATE employees SET wage=wage*2");
T.commit(); // NOTE: do this inside try block
}
catch (const exception &e)
{
cerr << e.what() << endl;
T.abort(); // Usually not needed; same happens when T's life ends.
}

Member Typedef Documentation

template<isolation_level ISOLATIONLEVEL = read_committed, readwrite_policy READWRITE = read_write>
typedef isolation_traits<ISOLATIONLEVEL> pqxx::transaction< ISOLATIONLEVEL, READWRITE >::isolation_tag

Constructor & Destructor Documentation

template<isolation_level ISOLATIONLEVEL = read_committed, readwrite_policy READWRITE = read_write>
pqxx::transaction< ISOLATIONLEVEL, READWRITE >::transaction ( connection_base C,
const std::string &  TName 
)
explicit

Create a transaction.

Parameters
CConnection for this transaction to operate on
TNameOptional name for transaction; must begin with a letter and may contain letters and digits only
template<isolation_level ISOLATIONLEVEL = read_committed, readwrite_policy READWRITE = read_write>
pqxx::transaction< ISOLATIONLEVEL, READWRITE >::transaction ( connection_base C)
explicit
template<isolation_level ISOLATIONLEVEL = read_committed, readwrite_policy READWRITE = read_write>
virtual pqxx::transaction< ISOLATIONLEVEL, READWRITE >::~transaction ( )
throw (
)
virtual

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