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

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

Public Types
using	size_type = result_size_type
using	difference_type = result_difference_type

Public Member Functions
	stateless_cursor (transaction_base &tx, std::string_view query, std::string_view cname, bool hold)
	Create cursor.
	stateless_cursor (transaction_base &tx, std::string_view adopted_cursor)
	Adopt an existing scrolling SQL cursor.
void	close () noexcept
	Close this cursor.
size_type	size ()
	Number of rows in cursor's result set.
result	retrieve (difference_type begin_pos, difference_type end_pos)
	Retrieve rows from begin_pos (inclusive) to end_pos (exclusive)
constexpr std::string const &	name () const noexcept
	Return this cursor's name.

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.

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 &  tx, std::string_view  query, std::string_view  cname, bool  hold  )

inline

Create cursor.

Parameters

tx	The transaction within which you want to create the cursor.
query	The SQL query whose results the cursor should traverse.
cname	A hint for the cursor's name. The actual SQL cursor's name will be based on this (though not necessarily identical).
hold	Create a WITH HOLD cursor? Such cursors stay alive after the transaction has ended, so you can continue to use it.

stateless_cursor() [2/2]

template<cursor_base::update_policy up, cursor_base::ownership_policy op>

pqxx::stateless_cursor< up, op >::stateless_cursor ( transaction_base &  tx, std::string_view  adopted_cursor  )

inline

Adopt an existing scrolling SQL cursor.

This lets you define a cursor yourself, and then wrap it in a libpqxx-managed stateless_cursor object.

Parameters

tx	The transaction within which you want to manage the cursor.
adopted_cursor	Your cursor's SQL name.

Member Function Documentation

close()

template<cursor_base::update_policy up, cursor_base::ownership_policy op>

void pqxx::stateless_cursor< up, op >::close ( )

inlinenoexcept

Close this cursor.

The destructor will do this for you automatically.

Closing a cursor is idempotent. Closing a cursor that's already closed does nothing.

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  )

inline

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

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

Parameters

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()

template<cursor_base::update_policy up, cursor_base::ownership_policy op>

size_type pqxx::stateless_cursor< up, op >::size ( )

inline

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.

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

• /build/reproducible-path/libpqxx-7.10.0/include/pqxx/cursor.hxx