pqxx::nontransaction Class Referencefinal
Simple "transaction" class offering no transactional integrity. More...
#include <nontransaction.hxx>
Inheritance diagram for pqxx::nontransaction:
Public Member Functions | |
| nontransaction (connection &c, std::string_view tname=""sv) | |
| Constructor. More... | |
| virtual | ~nontransaction () 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::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
Simple "transaction" class offering no transactional integrity.
nontransaction, like transaction or any other transaction_base-derived class, provides access to a database through a connection. Unlike its siblings, however, nontransaction does not maintain any kind of transactional integrity. This may be useful eg. for read-only access to the database that does not require a consistent, atomic view on its data; or for operations that are not allowed within a backend transaction, such as creating tables.
For queries that update the database, however, a real transaction is likely to be faster unless the transaction consists of only a single record update.
Also, you can keep a nontransaction open for as long as you like. Actual back-end transactions are limited in lifespan, and will sometimes fail just because they took too long to execute or were left idle for too long. This will not happen with a nontransaction (although the connection may still time out, e.g. when the network is unavailable for a very long time).
Any query executed in a nontransaction is committed immediately, and neither commit() nor abort() has any effect.
Database features that require a backend transaction, such as cursors or large objects, will not work in a nontransaction.
Constructor & Destructor Documentation
◆ nontransaction()
| pqxx::nontransaction::nontransaction | ( | connection & | c, |
| std::string_view | tname = ""sv |
||
| ) |
Constructor.
Create a "dummy" transaction.
- Parameters
-
c Connection that this "transaction" will operate on. name Optional name for the transaction, beginning with a letter and containing only letters and digits.
◆ ~nontransaction()
|
overridevirtual |
The documentation for this class was generated from the following file:
