libpqxx  7.3.1
pqxx::stateless_cursor< up, op > Class Template Reference

"Stateless cursor" class: easy API for retrieving parts of result sets More...

#include <cursor.hxx>

Public Types

using size_type = result_size_type
 
using difference_type = result_difference_type
 

Public Member Functions

 stateless_cursor (transaction_base &trans, std::string_view query, std::string_view cname, bool hold)
 Create cursor. More...
 
 stateless_cursor (transaction_base &trans, std::string_view adopted_cursor)
 Adopt existing scrolling SQL cursor. More...
 
void close () noexcept
 Close this cursor. The destructor will do this automatically. More...
 
size_type size ()
 Number of rows in cursor's result set. More...
 
result retrieve (difference_type begin_pos, difference_type end_pos)
 Retrieve rows from begin_pos (inclusive) to end_pos (exclusive) More...
 
std::string const & name () const noexcept
 Return this cursor's name. More...
 

Detailed Description

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
class pqxx::stateless_cursor< up, op >

"Stateless cursor" class: easy API for retrieving parts of result sets

This is a front-end for SQL cursors, but with a more C++-like API.

Actually, stateless_cursor feels entirely different from SQL cursors. You don't keep track of positions, fetches, and moves; you just say which rows you want. See the retrieve() member function.

Member Typedef Documentation

◆ difference_type

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
using pqxx::stateless_cursor< up, op >::difference_type = result_difference_type

◆ size_type

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
using pqxx::stateless_cursor< up, op >::size_type = result_size_type

Constructor & Destructor Documentation

◆ stateless_cursor() [1/2]

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
pqxx::stateless_cursor< up, op >::stateless_cursor ( transaction_base trans,
std::string_view  query,
std::string_view  cname,
bool  hold 
)

Create cursor.

References pqxx::cursor_base::random_access.

◆ stateless_cursor() [2/2]

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
pqxx::stateless_cursor< up, op >::stateless_cursor ( transaction_base trans,
std::string_view  adopted_cursor 
)

Adopt existing scrolling SQL cursor.

References pqxx::cursor_base::backward_all().

Member Function Documentation

◆ close()

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
void pqxx::stateless_cursor< up, op >::close ( )
noexcept

Close this cursor. The destructor will do this automatically.

◆ name()

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
std::string const& pqxx::stateless_cursor< up, op >::name ( ) const
noexcept

Return this cursor's name.

◆ retrieve()

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
result pqxx::stateless_cursor< up, op >::retrieve ( difference_type  begin_pos,
difference_type  end_pos 
)

Retrieve rows from begin_pos (inclusive) to end_pos (exclusive)

Rows are numbered starting from 0 to size()-1.

Parameters
begin_posFirst row to retrieve. May be one row beyond the end of the result set, to avoid errors for empty result sets. Otherwise, must be a valid row number in the result set.
end_posRow up to which to fetch. Rows are returned ordered from begin_pos to end_pos, i.e. in ascending order if begin_pos < end_pos but in descending order if begin_pos > end_pos. The end_pos may be arbitrarily inside or outside the result set; only existing rows are included in the result.

◆ size()

template<cursor_base::update_policy up, cursor_base::ownership_policy op>
size_type pqxx::stateless_cursor< up, op >::size ( )

Number of rows in cursor's result set.

Note
This function is not const; it may need to scroll to find the size of the result set.

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