libpqxx  7.0.1
pqxx::const_result_iterator Class Reference

Iterator for rows in a result. Use as result::const_iterator. More...

#include <result_iterator.hxx>

Inheritance diagram for pqxx::const_result_iterator:

Public Types

using iterator_category = std::random_access_iterator_tag
 
using value_type = row const
 
using pointer = row const *
 
using reference = row
 
using size_type = result_size_type
 
using difference_type = result_difference_type
 
- Public Types inherited from pqxx::row
using size_type = row_size_type
 
using difference_type = row_difference_type
 
using const_iterator = const_row_iterator
 
using iterator = const_iterator
 
using reference = field
 
using pointer = const_row_iterator
 
using const_reverse_iterator = const_reverse_row_iterator
 
using reverse_iterator = const_reverse_iterator
 

Public Member Functions

 const_result_iterator () noexcept
 
 const_result_iterator (row const &t) noexcept
 
Dereferencing operators
pointer operator-> () const
 
reference operator* () const
 
Manipulations
const_result_iterator operator++ (int)
 
const_result_iteratoroperator++ ()
 
const_result_iterator operator-- (int)
 
const_result_iteratoroperator-- ()
 
const_result_iteratoroperator+= (difference_type i)
 
const_result_iteratoroperator-= (difference_type i)
 
Comparisons
bool operator== (const_result_iterator const &i) const
 
bool operator!= (const_result_iterator const &i) const
 
bool operator< (const_result_iterator const &i) const
 
bool operator<= (const_result_iterator const &i) const
 
bool operator> (const_result_iterator const &i) const
 
bool operator>= (const_result_iterator const &i) const
 
- Public Member Functions inherited from pqxx::row
 row ()=default
 
const_iterator begin () const noexcept
 
const_iterator cbegin () const noexcept
 
const_iterator end () const noexcept
 
const_iterator cend () const noexcept
 
size_type size () const noexcept
 
void swap (row &) noexcept
 
result::size_type rownumber () const noexcept
 Row number, assuming this is a real row and not end()/rend(). More...
 
result::size_type num () const
 
row slice (size_type sbegin, size_type send) const
 
PQXX_PURE bool empty () const noexcept
 
PQXX_PURE bool operator== (row const &) const noexcept
 
bool operator!= (row const &rhs) const noexcept
 
reference front () const noexcept
 
reference back () const noexcept
 
const_reverse_row_iterator rbegin () const
 
const_reverse_row_iterator crbegin () const
 
const_reverse_row_iterator rend () const
 
const_reverse_row_iterator crend () const
 
reference operator[] (size_type) const noexcept
 
reference operator[] (char const []) const
 
reference operator[] (std::string const &s) const
 
reference at (size_type) const
 
reference at (char const []) const
 
reference at (std::string const &s) const
 
size_type column_number (std::string const &col_name) const
 Number of given column (throws exception if it doesn't exist). More...
 
size_type column_number (char const []) const
 Number of given column (throws exception if it doesn't exist). More...
 
oid column_type (size_type) const
 Return a column's type. More...
 
template<typename STRING >
oid column_type (STRING col_name) const
 Return a column's type. More...
 
oid column_table (size_type col_num) const
 What table did this column come from? More...
 
template<typename STRING >
oid column_table (STRING col_name) const
 What table did this column come from? More...
 
size_type table_column (size_type) const
 What column number in its table did this result column come from? More...
 
template<typename STRING >
size_type table_column (STRING col_name) const
 What column number in its table did this result column come from? More...
 

Friends

class pqxx::result
 

Arithmetic operators

const_result_iterator operator+ (difference_type, const_result_iterator const &)
 
const_result_iterator operator+ (difference_type) const
 
const_result_iterator operator- (difference_type) const
 
difference_type operator- (const_result_iterator const &) const
 

Additional Inherited Members

- Protected Member Functions inherited from pqxx::row
 row (result const &r, result_size_type i) noexcept
 
- Protected Attributes inherited from pqxx::row
result m_result
 Result set of which this is one row. More...
 
result::size_type m_index = 0
 Row number. More...
 
size_type m_begin = 0
 First column in slice. This row ignores lower-numbered columns. More...
 
size_type m_end = 0
 End column in slice. This row only sees lower-numbered columns. More...
 

Detailed Description

Iterator for rows in a result. Use as result::const_iterator.

A result, once obtained, cannot be modified. Therefore there is no plain iterator type for result. However its const_iterator type can be used to inspect its rows without changing them.

Member Typedef Documentation

◆ difference_type

◆ iterator_category

using pqxx::const_result_iterator::iterator_category = std::random_access_iterator_tag

◆ pointer

◆ reference

◆ size_type

◆ value_type

Constructor & Destructor Documentation

◆ const_result_iterator() [1/2]

pqxx::const_result_iterator::const_result_iterator ( )
noexcept

◆ const_result_iterator() [2/2]

pqxx::const_result_iterator::const_result_iterator ( row const &  t)
noexcept

Member Function Documentation

◆ operator!=()

bool pqxx::const_result_iterator::operator!= ( const_result_iterator const &  i) const

References pqxx::row::m_index.

◆ operator*()

reference pqxx::const_result_iterator::operator* ( ) const

◆ operator+()

const_result_iterator pqxx::const_result_iterator::operator+ ( result::difference_type  o) const

◆ operator++() [1/2]

pqxx::const_result_iterator pqxx::const_result_iterator::operator++ ( int  )

◆ operator++() [2/2]

const_result_iterator& pqxx::const_result_iterator::operator++ ( )

◆ operator+=()

const_result_iterator& pqxx::const_result_iterator::operator+= ( difference_type  i)

◆ operator-() [1/2]

const_result_iterator pqxx::const_result_iterator::operator- ( result::difference_type  o) const

Referenced by pqxx::operator+().

◆ operator-() [2/2]

result::difference_type pqxx::const_result_iterator::operator- ( const_result_iterator const &  i) const

References pqxx::row::num().

◆ operator--() [1/2]

pqxx::const_result_iterator pqxx::const_result_iterator::operator-- ( int  )

◆ operator--() [2/2]

const_result_iterator& pqxx::const_result_iterator::operator-- ( )

◆ operator-=()

const_result_iterator& pqxx::const_result_iterator::operator-= ( difference_type  i)

◆ operator->()

pointer pqxx::const_result_iterator::operator-> ( ) const

The iterator "points to" its own row, which is also itself. This allows a result to be addressed as a two-dimensional container without going through the intermediate step of dereferencing the iterator. I hope this works out to be similar to C pointer/array semantics in useful cases.

IIRC Alex Stepanov, the inventor of the STL, once remarked that having this as standard behaviour for pointers would be useful in some algorithms. So even if this makes me look foolish, I would seem to be in distinguished company.

◆ operator<()

bool pqxx::const_result_iterator::operator< ( const_result_iterator const &  i) const

References pqxx::row::m_index.

◆ operator<=()

bool pqxx::const_result_iterator::operator<= ( const_result_iterator const &  i) const

References pqxx::row::m_index.

◆ operator==()

bool pqxx::const_result_iterator::operator== ( const_result_iterator const &  i) const

References pqxx::row::m_index.

◆ operator>()

bool pqxx::const_result_iterator::operator> ( const_result_iterator const &  i) const

References pqxx::row::m_index.

◆ operator>=()

bool pqxx::const_result_iterator::operator>= ( const_result_iterator const &  i) const

Friends And Related Function Documentation

◆ operator+

const_result_iterator operator+ ( result::difference_type  o,
const_result_iterator const &  i 
)
friend

◆ pqxx::result

friend class pqxx::result
friend

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