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oralib::parameter Class Reference

Encapsulates a named variable (AKA bound variable, parameter). More...

#include <parameter.h>

List of all members.

Public Methods
void	to_null (void)
	Sets parameter value to null.
parameter &	operator= (Pstr text)
	Sets parameter value to a text.
parameter &	operator= (double value)
	Sets parameter value to a double.
parameter &	operator= (long value)
	Sets parameter value to a long.
parameter &	operator= (const datetime &d)
	Sets parameter value to a date/time.
bool	is_null (void) const
	Returns whether parameter is having null value.
	operator Pstr (void) const
	Returns parameter value as text.
Pstr	as_string (void) const
	Returns parameter value as text.
	operator double (void) const
	Returns parameter value as double.
double	as_double (void) const
	Returns parameter value as double.
	operator long (void) const
	Returns parameter value as long.
long	as_long (void) const
	Returns parameter value as long.
	operator datetime (void) const
	Returns parameter value as date/time.
datetime	as_datetime (void) const
	Returns parameter value as date/time.
	operator resultset & (void)
	Returns parameter value as resultset. Internally cached - several calls will return same instance.
resultset &	as_resultset (void)
	Returns parameter value as resultset. Internally cached - several calls will return same instance.
void	release (void)
	Releases resources allocated for the bound variable (currently does nothing).
Friends
class	statement

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Detailed Description

Encapsulates a named variable (AKA bound variable, parameter).

Parameters (bound variables, named variables) could be used to pass data to Oracle as a part of SQL or PL/SQL statement. Although data could be part of SQL statement's text, for example "insert into TABLE_NAME (ID, NAME) values (1000, 'Your name goes here')", in most cases that data would be dynamic - that is a data, entered by the operator. By using parameters (names prefixed by colons ':') statement will be "insert into TABLE_NAME (ID, NAME) values (:ID, :NAME)" and parameter values will be initialized in run time.

Each parameter is having a data type (text, numeric, cursor, etc.) initialized in the time parameter is bound (statement::bind). Only resultsets (that is "REF CURSOR") are output-only. Text, numeric and date/time parameters could be input/output.

Supported data types are described in oralib::DataTypesEnum and currently are: text, numeric, date/time and resultsets.

parameter class provides C++ friendly interface by exposing overloaded operators, so parameter value could be set simply by using assignment operator and could be read by using C-style type casts. Parameter value can also be read by using methods, such as as_string() and as_long() for example.

to_null() and is_null() are NULL-asignment and NULL-test methods.

Any attempt to read parameter value in type, different than parameter's data type will cause an exception (for example a request for text as numeric). Parameters having NULL value will throw an exception if their value is requested - is_null() should be used when parameter could have NULL value.

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

• parameter.h
• parameter.txt

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