cppdb::result Class Reference

This object represents query result. More...

#include <cppdb/frontend.h>

List of all members.

Public Member Functions
	result ()
	~result ()
	result (result const &)
result const &	operator= (result const &)
int	cols ()
bool	next ()
int	index (std::string const &n)
int	find_column (std::string const &name)
std::string	name (int col)
bool	is_null (int col)
bool	is_null (std::string const &n)
void	clear ()
void	rewind_column ()
bool	empty ()
bool	fetch (int col, short &v)
bool	fetch (int col, unsigned short &v)
bool	fetch (int col, int &v)
bool	fetch (int col, unsigned &v)
bool	fetch (int col, long &v)
bool	fetch (int col, unsigned long &v)
bool	fetch (int col, long long &v)
bool	fetch (int col, unsigned long long &v)
bool	fetch (int col, float &v)
bool	fetch (int col, double &v)
bool	fetch (int col, long double &v)
bool	fetch (int col, std::string &v)
bool	fetch (int col, std::tm &v)
bool	fetch (int col, std::ostream &v)
bool	fetch (std::string const &n, short &v)
bool	fetch (std::string const &n, unsigned short &v)
bool	fetch (std::string const &n, int &v)
bool	fetch (std::string const &n, unsigned &v)
bool	fetch (std::string const &n, long &v)
bool	fetch (std::string const &n, unsigned long &v)
bool	fetch (std::string const &n, long long &v)
bool	fetch (std::string const &n, unsigned long long &v)
bool	fetch (std::string const &n, float &v)
bool	fetch (std::string const &n, double &v)
bool	fetch (std::string const &n, long double &v)
bool	fetch (std::string const &n, std::string &v)
bool	fetch (std::string const &n, std::tm &v)
bool	fetch (std::string const &n, std::ostream &v)
bool	fetch (short &v)
bool	fetch (unsigned short &v)
bool	fetch (int &v)
bool	fetch (unsigned &v)
bool	fetch (long &v)
bool	fetch (unsigned long &v)
bool	fetch (long long &v)
bool	fetch (unsigned long long &v)
bool	fetch (float &v)
bool	fetch (double &v)
bool	fetch (long double &v)
bool	fetch (std::string &v)
bool	fetch (std::tm &v)
bool	fetch (std::ostream &v)
template<typename T >
T	get (std::string const &name)
template<typename T >
T	get (std::string const &name, T const &def)
template<typename T >
T	get (int col)
template<typename T >
T	get (int col, T const &def)
template<typename T >
result &	operator>> (tags::into_tag< T > ref)
template<typename T >
result &	operator>> (T &value)
Friends
class	statement

---

Detailed Description

This object represents query result.

This object and it is generally created by statement::query() call, default constructor is provided for consistency, but access to any member function with exception of empty() would throw an exception.

---

Constructor & Destructor Documentation

cppdb::result::result

(

)

Create an empty result, it is not useful except for having default constructor

cppdb::result::~result

(

)

Destroys the result, note, if the result of statement is not destroyed, it would not be returned to statements cache.

cppdb::result::result

(

result const &

)

Copy result, note it only keeps the reference to actual object so copy is just copy of the reference

---

Member Function Documentation

void cppdb::result::clear

(

)

Clears the result, no further use of the result should be done until it is assigned again with a new statement result.

It is useful when you want to release all data and return the statement to cache

int cppdb::result::cols

(

)

Return the number of columns in the result

bool cppdb::result::empty

(

)

Check if the current row is empty, it is in 3 cases:

1. Empty result
2. next() wasn't called first time
3. next() returned false;

bool cppdb::result::fetch	(	int	col,
		short &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		unsigned short &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		int &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		unsigned &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		long &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		unsigned long &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		long long &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		unsigned long long &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		float &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		double &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		long double &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		std::string &	v
	)

Fetch a textual value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same, if possible it converts it into textual representation.

bool cppdb::result::fetch	(	int	col,
		std::tm &	v
	)

Fetch a value from column col (starting from 0) into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

bool cppdb::result::fetch	(	int	col,
		std::ostream &	v
	)

Fetch a binary large object value from column col (starting from 0) into a stream v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not blob, it may throw bad_value_cast()

bool cppdb::result::fetch	(	std::string const &	n,
		short &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		unsigned short &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		int &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		unsigned &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		long &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		unsigned long &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		long long &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		unsigned long long &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		float &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		double &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		long double &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		std::string &	v
	)

Fetch a textual value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same, if possible it converts it into textual representation. If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		std::tm &	v
	)

Fetch a value from column named n into v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch	(	std::string const &	n,
		std::ostream &	v
	)

Fetch a binary large object value from column named name into a stream v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not blob, it may throw bad_value_cast(). If the n value is invalid throws invalid_column exception

bool cppdb::result::fetch

(

short &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

unsigned short &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

int &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

unsigned &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

long &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

unsigned long &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

long long &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

unsigned long long &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

float &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

double &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

long double &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

std::string &

v

)

Fetch a textual value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same, if possible it converts it into textual representation.

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

std::tm &

v

)

Fetch a value from the next column in the row starting from the first one. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not same it tries to cast the data, if casting fails or the data is out of the type range, throws bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

bool cppdb::result::fetch

(

std::ostream &

v

)

Fetch a blob value from the next column in the row starting from the first one into stream v. Returns false if the value in NULL and v is not updated, otherwise returns true.

If the data type is not blob, it may throw bad_value_cast().

If fetch was called more times then cols() it throws invalid_column exception, to use it once again from the beginning on the same row call rewind_column() member function. It is not required to call rewind_column() after calling next() as column index is reset automatically.

int cppdb::result::find_column

(

std::string const &

name

)

Convert column name n to its index, returns -1 if the name is not valid.

template<typename T >

T cppdb::result::get

(

std::string const &

name

)

[inline]

Get a value of type T from column named name. If the column is null throws null_value_fetch(), if the column name is invalid throws invalid_column, if the column value cannot be converted to type T (see fetch functions) it throws bad_value_cast.

template<typename T >

T cppdb::result::get	(	std::string const &	name,
		T const &	def
	)		[inline]

Get a value of type T from column named name. If the column is null returns def, if the column name is invalid throws invalid_column, if the column value cannot be converted to type T (see fetch functions) it throws bad_value_cast.

template<typename T >

T cppdb::result::get

(

int

col

)

[inline]

Get a value of type T from column col (starting from 0). If the column is null throws null_value_fetch(), if the column index is invalid throws invalid_column, if the column value cannot be converted to type T (see fetch functions) it throws bad_value_cast.

template<typename T >

T cppdb::result::get	(	int	col,
		T const &	def
	)		[inline]

Get a value of type T from column col (starting from 0). If the column is null returns def, if the column index is invalid throws invalid_column, if the column value cannot be converted to type T (see fetch functions) it throws bad_value_cast.

int cppdb::result::index

(

std::string const &

n

)

Convert column name n to its index, throws invalid_column if the name is not valid.

bool cppdb::result::is_null

(

int

col

)

Return true if the column number col (starting from 0) has NULL value

bool cppdb::result::is_null

(

std::string const &

n

)

Return true if the column named n has NULL value

std::string cppdb::result::name

(

int

col

)

Convert column index to column name, throws invalid_column if col is not in range 0<= col < cols()

bool cppdb::result::next

(

)

Move forward to next row, returns false if no more rows available.

Notes:

• You should call next() at least once before you use fetch() functions
• You must not call fetch() functions if next() returned false, it would cause empty_row_access exception.

result const& cppdb::result::operator=

(

result const &

)

Assign result, note it only keeps the reference to actual object so assignment is just copy of the reference

template<typename T >

result& cppdb::result::operator>>

(

tags::into_tag< T >

ref

)

[inline]

Syntactic sugar, used together with into() function.

res << into(x,y) is same as

 y = res.fetch(x) ? not_null_value : null_value 

template<typename T >

result& cppdb::result::operator>>

(

T &

value

)

[inline]

Syntactic sugar, same as fetch(value)

void cppdb::result::rewind_column

(

)

Reset current column index, so fetch without column index can be used once again

---

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

• cppdb/frontend.h