RWDBExprFuncDef0 Class Reference
[Expressions]

Specialization of the base class RWDBExprFormDefinition used to define SQL functions that take no parameters. More...

#include <rw/db/func.h>

Inheritance diagram for RWDBExprFuncDef0:

List of all members.

Public Member Functions
	RWDBExprFuncDef0 (const RWCString &functionName)
virtual RWDBExpr	operator() ()
Private Member Functions
virtual RWDBExpr	operator() (const RWDBExpr &)
virtual RWDBExpr	operator() (const RWDBExpr &, const RWDBExpr &)
virtual RWDBExpr	operator() (const RWDBExpr &, const RWDBExpr &, const RWDBExpr &)
virtual RWDBExpr	operator() (const RWDBExpr &, const RWDBExpr &, const RWDBExpr &, const RWDBExpr &)

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Detailed Description

RWDBExprFuncDef0 is a specialization of the base class RWDBExprFormDefinition. This class provides a simplified mechanism for defining SQL functions taking no parameters. Unlike the base class, this class does not require positional placeholders in its function definitions. Also, since the number of required parameters is fixed, compile-time checking can be done on the number of parameters actually passed.

Synopsis

 #include <rw/db/func.h>
 
 RWDBExprFuncDef0 myFunc("myFunc");

Related Classes

RWDBCritFuncDef0 provides a parallel mechanism for defining an RWDBCriterion, rather than an RWDBExpr.

The RWDBExprFormDefinition base class may be used directly to gain additional flexibility.

See RWDBExpr for details on SQL expressions in the DB Interface Module, as well as for a complete listing of predefined SQL functions.

Examples

Please refer to the example in RWDBExprFuncDef3.

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Constructor & Destructor Documentation

RWDBExprFuncDef0::RWDBExprFuncDef0

(

const RWCString &

functionName

)

Creates an RWDBExprFuncDef0 for a functional expression that takes no parameters. After such an RWDBExprFuncDef0 is instantiated, functionName may be used as though it were a predefined function.

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Member Function Documentation

virtual RWDBExpr RWDBExprFuncDef0::operator()	(	const RWDBExpr &	,
		const RWDBExpr &	,
		const RWDBExpr &	,
		const RWDBExpr &
	)			[private, virtual]

Not applicable to this class. This class defines SQL functions taking no parameters.

Reimplemented from RWDBExprFormDefinition.

virtual RWDBExpr RWDBExprFuncDef0::operator()	(	const RWDBExpr &	,
		const RWDBExpr &	,
		const RWDBExpr &
	)			[private, virtual]

Not applicable to this class. This class defines SQL functions taking no parameters.

Reimplemented from RWDBExprFormDefinition.

virtual RWDBExpr RWDBExprFuncDef0::operator()	(	const RWDBExpr &	,
		const RWDBExpr &
	)			[private, virtual]

Not applicable to this class. This class defines SQL functions taking no parameters.

Reimplemented from RWDBExprFormDefinition.

virtual RWDBExpr RWDBExprFuncDef0::operator()

(

const RWDBExpr &

)

[private, virtual]

Not applicable to this class. This class defines SQL functions taking no parameters.

Reimplemented from RWDBExprFormDefinition.

virtual RWDBExpr RWDBExprFuncDef0::operator()

(

)

[virtual]

Returns an RWDBExpr in the form of a function with zero parameters whose name is the name which was passed to self's constructor.

Reimplemented from RWDBExprFormDefinition.