libpqxx
7.0.5
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"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 |
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 |
"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.
using pqxx::stateless_cursor< up, op >::difference_type = result_difference_type |
using pqxx::stateless_cursor< up, op >::size_type = result_size_type |
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.
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().
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noexcept |
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noexcept |
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.
begin_pos | First 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_pos | Row 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_type pqxx::stateless_cursor< up, op >::size | ( | ) |
Number of rows in cursor's result set.