libpqxx
4.0.1
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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()) | |
Nest a subtransaction nested in another transaction. | |
subtransaction (subtransaction &T, const std::string &Name=std::string()) | |
Nest a subtransaction in another subtransaction. | |
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transactionfocus (transaction_base &t) | |
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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 |
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virtual | ~dbtransaction () |
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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. | |
std::string | quote_raw (const unsigned char str[], size_t len) const |
Binary-escape and quote a binarystring for use as an SQL constant. | |
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. | |
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 | |
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typedef isolation_traits < read_committed > | isolation_tag |
If nothing else is known, our isolation level is at least read_committed. | |
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void | register_me () |
void | unregister_me () throw () |
void | reg_pending_error (const std::string &) throw () |
bool | registered () const throw () |
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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. | |
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static std::string | fullname (const std::string &ttype, const std::string &isolation) |
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transaction_base & | m_Trans |
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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:
(This is just an example. If you really wanted to do drop a table without an error if it doesn't exist, you'd use DROP TABLE IF EXISTS.)
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 |
Nest a subtransaction nested in another transaction.
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explicit |
Nest a subtransaction in another subtransaction.