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libpqxx
3.1.1
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"Transaction" nested within another transaction More...
#include <subtransaction.hxx>
Public Member Functions | |
| subtransaction (dbtransaction &T, const std::string &Name=std::string()) | |
Public Member Functions inherited from pqxx::internal::transactionfocus | |
| transactionfocus (transaction_base &t) | |
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 |
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. | |
| void | abort () |
| Abort the transaction. | |
| std::string | esc (const char str[]) const |
| Escape string for use as SQL string literal in this transaction. | |
| std::string | esc (const char str[], size_t maxlen) const |
| Escape string for use as SQL string literal in this transaction. | |
| std::string | esc (const std::string &str) const |
| Escape string for use as SQL string literal in this transaction. | |
| std::string | esc_raw (const unsigned char str[], size_t len) const |
| Escape binary data for use as SQL string literal in this transaction. | |
| std::string | esc_raw (const std::string &) const |
| Escape binary data for use as SQL string literal in this transaction. | |
| template<typename T > | |
| std::string | quote (const T &t) const |
| Represent object as SQL string, including quoting & escaping. | |
| result | exec (const std::string &Query, const std::string &Desc=std::string()) |
| Execute query. | |
| result | exec (const std::stringstream &Query, const std::string &Desc=std::string()) |
| internal::parameterized_invocation | parameterized (const std::string &query) |
| Parameterize a statement. | |
| connection_base & | conn () const |
| Connection this transaction is running in. | |
| void | set_variable (const std::string &Var, const std::string &Val) |
| Set session variable in this connection. | |
| std::string | get_variable (const std::string &) |
| Get currently applicable value of variable. | |
| prepare::invocation | prepared (const std::string &statement=std::string()) |
| Execute prepared statement. | |
| void | process_notice (const char Msg[]) const |
| Have connection process warning message. | |
| void | process_notice (const std::string &Msg) const |
| Have connection process warning message. | |
Additional Inherited Members | |
Public Types inherited from pqxx::transaction_base | |
| typedef isolation_traits < read_committed > | isolation_tag |
| If nothing else is known, our isolation level is at least read_committed. | |
Protected Member Functions inherited from pqxx::internal::transactionfocus | |
| void | register_me () |
| void | unregister_me () throw () |
| void | reg_pending_error (const std::string &) throw () |
| bool | registered () const throw () |
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. | |
| virtual void | do_begin () |
| Sensible default implemented here: begin backend transaction. | |
| virtual result | do_exec (const char Query[]) |
| Sensible default implemented here: perform query. | |
| virtual void | do_commit ()=0 |
| To be implemented by derived class: commit backend transaction. | |
| virtual void | do_abort () |
| Sensible default implemented here: abort backend transaction. | |
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::internal::transactionfocus | |
| transaction_base & | m_Trans |
Protected Attributes inherited from pqxx::transaction_base | |
| internal::reactivation_avoidance_counter | m_reactivation_avoidance |
| Resources allocated in this transaction that make reactivation impossible. | |
"Transaction" nested within another transaction
A subtransaction can be executed inside a backend transaction, or inside another subtransaction. This can be useful when, for example, statements in a transaction may harmlessly fail and you don't want them to abort the entire transaction. Here's an example of how a temporary table may be dropped before re-creating it, without failing if the table did not exist:
There are no isolation levels inside a transaction. They are not needed because all actions within the same backend transaction are always performed sequentially anyway.
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explicit |