pqxx::transaction< ISOLATION, READWRITE > Class Template Reference

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

#include <transaction.hxx>

Inheritance diagram for pqxx::transaction< ISOLATION, READWRITE >:

Public Member Functions
	transaction (connection &c, std::string_view tname)
	Begin a transaction. More...
	transaction (connection &c)
	Begin a transaction. More...
virtual	~transaction () noexcept override
Public Member Functions inherited from pqxx::transaction_base
	transaction_base ()=delete
	transaction_base (transaction_base const &)=delete
	transaction_base (transaction_base &&)=delete
transaction_base &	operator= (transaction_base const &)=delete
transaction_base &	operator= (transaction_base &&)=delete
virtual	~transaction_base ()=0
void	commit ()
	Commit the transaction. More...
void	abort ()
	Abort the transaction. More...
connection &	conn () const
	The connection in which this transaction lives. More...
void	set_variable (std::string_view var, std::string_view value)
	Set session variable using SQL "SET" command. More...
std::string	get_variable (std::string_view)
	Read session variable using SQL "SHOW" command. More...
std::string_view	name () const noexcept
	Transaction name, if you passed one to the constructor; or empty string. More...
template<>
zview	query_value (zview query, std::string_view desc)=delete
	Forbidden specialisation: underlying buffer immediately goes out of scope. More...
std::string	esc (char const text[]) const
	Escape string for use as SQL string literal in this transaction. More...
std::string	esc (char const text[], std::size_t maxlen) const
	Escape string for use as SQL string literal in this transaction. More...
std::string	esc (std::string_view text) const
	Escape string for use as SQL string literal in this transaction. More...
std::string	esc_raw (unsigned char const data[], std::size_t len) const
	Escape binary data for use as SQL string literal in this transaction. More...
std::string	esc_raw (zview) const
	Escape binary data for use as SQL string literal in this transaction. More...
std::string	unesc_raw (zview text) const
	Unescape binary data, e.g. from a table field or notification payload. More...
std::string	unesc_raw (char const *text) const
	Unescape binary data, e.g. from a table field or notification payload. More...
template<typename T >
std::string	quote (T const &t) const
	Represent object as SQL string, including quoting & escaping. More...
std::string	quote_raw (unsigned char const bin[], std::size_t len) const
	Binary-escape and quote a binary string for use as an SQL constant. More...
std::string	quote_raw (zview bin) const
	Binary-escape and quote a binary string for use as an SQL constant. More...
std::string	quote_name (std::string_view identifier) const
	Escape an SQL identifier for use in a query. More...
std::string	esc_like (std::string_view bin, char escape_char='\\') const
	Escape string for literal LIKE match. More...
result	exec (std::string_view query, std::string_view desc=std::string_view{})
	Execute a command. More...
result	exec (std::stringstream const &query, std::string_view desc=std::string_view{})
	Execute a command. More...
result	exec0 (zview query, std::string_view desc=std::string_view{})
	Execute command, which should return zero rows of data. More...
row	exec1 (zview query, std::string_view desc=std::string_view{})
	Execute command returning a single row of data. More...
result	exec_n (result::size_type rows, zview query, std::string_view desc=std::string_view{})
	Execute command, expect given number of rows. More...
template<typename TYPE >
TYPE	query_value (zview query, std::string_view desc=std::string_view{})
	Perform query, expecting exactly 1 row with 1 field, and convert it. More...
template<typename... TYPE>
auto	stream (std::string_view query)
	Execute a query, and loop over the results row by row. More...
template<typename... Args>
result	exec_params (zview query, Args &&...args)
	Execute an SQL statement with parameters. More...
template<typename... Args>
row	exec_params1 (zview query, Args &&...args)
template<typename... Args>
result	exec_params0 (zview query, Args &&...args)
template<typename... Args>
result	exec_params_n (std::size_t rows, zview query, Args &&...args)
template<typename... Args>
result	exec_prepared (zview statement, Args &&...args)
	Execute a prepared statement, with optional arguments. More...
template<typename... Args>
row	exec_prepared1 (zview statement, Args &&...args)
	Execute a prepared statement, and expect a single-row result. More...
template<typename... Args>
result	exec_prepared0 (zview statement, Args &&...args)
	Execute a prepared statement, and expect a result with zero rows. More...
template<typename... Args>
result	exec_prepared_n (result::size_type rows, zview statement, Args &&...args)
	Execute a prepared statement, expect a result with given number of rows. More...
void	process_notice (char const msg[]) const
	Have connection process a warning message. More...
void	process_notice (zview msg) const
	Have connection process a warning message. More...

Additional Inherited Members
Protected Member Functions inherited from pqxx::internal::basic_transaction
	basic_transaction (connection &c, zview begin_command, std::string_view tname)
	basic_transaction (connection &c, zview begin_command, std::string &&tname)
	basic_transaction (connection &c, zview begin_command)
virtual	~basic_transaction () noexcept override=0
Protected Member Functions inherited from pqxx::dbtransaction
	dbtransaction (connection &c)
	Begin transaction. More...
	dbtransaction (connection &c, std::string_view tname)
	Begin transaction. More...
	dbtransaction (connection &c, std::string_view tname, std::shared_ptr< std::string > rollback_cmd)
	Begin transaction. More...
Protected Member Functions inherited from pqxx::transaction_base
	transaction_base (connection &c, std::string_view tname, std::shared_ptr< std::string > rollback_cmd)
	Create a transaction (to be called by implementation classes only). More...
	transaction_base (connection &c, std::string_view tname)
	Create a transaction (to be called by implementation classes only). More...
	transaction_base (connection &c)
	Create a transaction (to be called by implementation classes only). More...
void	register_transaction ()
	Register this transaction with the connection. More...
void	close () noexcept
	End transaction. To be called by implementing class' destructor. More...
virtual void	do_abort ()
	Transaction type-specific way of aborting a transaction. More...
void	set_rollback_cmd (std::shared_ptr< std::string > cmd)
	Set the rollback command. More...
result	direct_exec (std::string_view, std::string_view desc=""sv)
	Execute query on connection directly. More...
result	direct_exec (std::shared_ptr< std::string >, std::string_view desc=""sv)

Detailed Description

template<isolation_level ISOLATION = isolation_level::read_committed, write_policy READWRITE = write_policy::read_write>
class pqxx::transaction< ISOLATION, READWRITE >

Standard back-end transaction, templatised on isolation level.

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

Usage example: double all wages.

extern connection C;
work T(C);
try
{
  T.exec0("UPDATE employees SET wage=wage*2");
  T.commit();   // NOTE: do this inside try block
}
catch (exception const &e)
{
  cerr << e.what() << endl;
  T.abort();            // Usually not needed; same happens when T's life ends.
}

Constructor & Destructor Documentation

transaction() [1/2]

template<isolation_level ISOLATION = isolation_level::read_committed, write_policy READWRITE = write_policy::read_write>

pqxx::transaction< ISOLATION, READWRITE >::transaction	(	connection &	c,
		std::string_view	tname
	)

Begin a transaction.

Parameters

c	Connection for this transaction to operate on.
tname	Optional name for transaction. Must begin with a letter and may contain letters and digits only.

transaction() [2/2]

template<isolation_level ISOLATION = isolation_level::read_committed, write_policy READWRITE = write_policy::read_write>

pqxx::transaction< ISOLATION, READWRITE >::transaction ( connection &  c )

explicit

Begin a transaction.

Parameters

c	Connection for this transaction to operate on.
tname	Optional name for transaction. Must begin with a letter and may contain letters and digits only.

~transaction()

template<isolation_level ISOLATION = isolation_level::read_committed, write_policy READWRITE = write_policy::read_write>

virtual pqxx::transaction< ISOLATION, READWRITE >::~transaction ( )

overridevirtualnoexcept

---

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

• transaction.hxx