RWDBSimpleCaseExpr Class Reference

Used to build simple CASE expressions. More...

#include <rw/db/expr.h>

Inheritance diagram for RWDBSimpleCaseExpr:

Public Member Functions
	RWDBSimpleCaseExpr (const RWDBExpr &input)
	RWDBSimpleCaseExpr (const RWDBSimpleCaseExpr &simpleCaseExpr)
void	else_ (const RWDBExpr &elseExpr)
RWDBSimpleCaseExpr &	operator= (const RWDBSimpleCaseExpr &simpleCaseExpr)
void	when (const RWDBExpr &whenExpr, const RWDBExpr &thenExpr)
Public Member Functions inherited from RWDBExpr
	RWDBExpr ()
	RWDBExpr (char value)
	RWDBExpr (const char *value)
	RWDBExpr (const RWBasicUString &value)
	RWDBExpr (const RWCollection &collection)
	RWDBExpr (const RWCString &value)
	RWDBExpr (const RWDate &value)
	RWDBExpr (const RWDateTime &value)
	RWDBExpr (const RWDBBlob &value)
	RWDBExpr (const RWDBColumn &column)
	RWDBExpr (const RWDBColumn &left, const RWDBExpr &right)
	RWDBExpr (const RWDBColumn &left, const RWDBValue &right)
	RWDBExpr (const RWDBDateTime &value)
	RWDBExpr (const RWDBDuration &value)
	RWDBExpr (const RWDBExpr &expr)
	RWDBExpr (const RWDBMBString &value)
	RWDBExpr (const RWDBSelectorBase &subSelect)
	RWDBExpr (const RWDBTable &)
	RWDBExpr (const RWDBValue &value, bool usePhraseBook=true)
	RWDBExpr (const RWDecimalPortable &value)
	RWDBExpr (const RWTime &value)
	RWDBExpr (const RWWString &value)
	RWDBExpr (const wchar_t *value)
	RWDBExpr (double value)
	RWDBExpr (float value)
	RWDBExpr (int value)
	RWDBExpr (long double value)
	RWDBExpr (long int value)
	RWDBExpr (long long value)
	RWDBExpr (RWDBValueManip manip)
	RWDBExpr (short value)
	RWDBExpr (unsigned char value)
	RWDBExpr (unsigned int value)
	RWDBExpr (unsigned long int value)
	RWDBExpr (unsigned long long value)
	RWDBExpr (unsigned short value)
RWCString	asString (const RWDBPhraseBook &phraseBook, AsStringControlFlag control=normal) const
RWDBCriterion	between (const RWDBExpr &expression1, const RWDBExpr &expression2) const
RWDBCriterion	in (const RWDBExpr &expression1) const
RWDBCriterion	isNull (void) const
bool	isValid (void) const
RWDBCriterion	leftOuterJoin (const RWDBExpr &expression) const
RWDBCriterion	like (const RWDBExpr &expression1) const
RWDBCriterion	matchUnique (const RWDBExpr &expression1) const
RWDBExpr &	operator= (const RWDBExpr &expr)
RWDBCriterion	rightOuterJoin (const RWDBExpr &expression) const

Additional Inherited Members
Public Types inherited from RWDBExpr
enum	AsStringControlFlag { normal , suppressTagsOnColumns , noPlaceHolder , placeHolderNotRecommended }
Related Symbols inherited from RWDBExpr
RWDBCriterion	operator! (const RWDBCriterion &)
RWDBCriterion	operator!= (const RWDBExpr &, const RWDBExpr &)
RWDBExpr	operator% (const RWDBExpr &, const RWDBExpr &)
RWDBCriterion	operator&& (const RWDBCriterion &, const RWDBCriterion &)
RWDBExpr	operator* (const RWDBExpr &, const RWDBExpr &)
RWDBExpr	operator+ (const RWDBExpr &)
RWDBExpr	operator+ (const RWDBExpr &, const RWDBExpr &)
RWDBExpr	operator- (const RWDBExpr &)
RWDBExpr	operator- (const RWDBExpr &, const RWDBExpr &)
RWDBExpr	operator/ (const RWDBExpr &, const RWDBExpr &)
RWDBCriterion	operator< (const RWDBExpr &, const RWDBExpr &)
RWDBCriterion	operator<= (const RWDBExpr &, const RWDBExpr &)
RWDBCriterion	operator== (const RWDBExpr &, const RWDBExpr &)
RWDBCriterion	operator> (const RWDBExpr &, const RWDBExpr &)
RWDBCriterion	operator>= (const RWDBExpr &, const RWDBExpr &)
RWDBCriterion	operator|| (const RWDBCriterion &, const RWDBCriterion &)
RWDBExpr	rwdbAvg (const RWDBExpr &expr)
RWDBExpr	rwdbCast (const RWDBExpr &expr, const RWDBValue &type)
RWDBExpr	rwdbCast (const RWDBExpr &expr, const RWDBValue &typeName, const RWDBExpr &formatString)
RWDBExpr	rwdbCast (const RWDBExpr &expr, const RWDBValue &typeName, const RWDBExpr &formatString, const RWDBExpr &secondaryFormat)
RWDBExpr	rwdbCharLength (const RWDBExpr &expr)
RWDBExpr	rwdbCount ()
RWDBExpr	rwdbCount (const RWDBExpr &expr)
RWDBExpr	rwdbCountDistinct (const RWDBExpr &expr)
RWDBExpr	rwdbCurrentUser ()
RWDBCriterion	rwdbExists (const RWDBSelectorBase &select)
RWDBExpr	rwdbLower (const RWDBExpr &expr)
RWDBExpr	rwdbMax (const RWDBExpr &expr)
RWDBExpr	rwdbMin (const RWDBExpr &expr)
RWDBExpr	rwdbName (const RWCString &name, const RWDBExpr &expr)
RWDBExpr	rwdbPosition (const RWDBExpr &expr1, const RWDBExpr &expr2)
RWDBExpr	rwdbSessionUser ()
RWDBExpr	rwdbSubString (const RWDBExpr &expr1, const RWDBExpr &expr2)
RWDBExpr	rwdbSubString (const RWDBExpr &expr1, const RWDBExpr &expr2, const RWDBExpr &expr3)
RWDBExpr	rwdbSum (const RWDBExpr &expr)
RWDBExpr	rwdbSystemDateTime ()
RWDBExpr	rwdbSystemUser ()
RWDBExpr	rwdbTrimBoth (const RWDBExpr &expr1, const RWDBExpr &expr2)
RWDBExpr	rwdbTrimLeading (const RWDBExpr &expr1, const RWDBExpr &expr2)
RWDBExpr	rwdbTrimTrailing (const RWDBExpr &expr1, const RWDBExpr &expr2)
RWDBExpr	rwdbUpper (const RWDBExpr &expr)

Detailed Description

RWDBSimpleCaseExpr represents a specialized type of RWDBExpr used to specify a simple SQL CASE expression.

Synopsis

#include <rw/db/expr.h>
 
RWDBSimpleCaseExpr caseExpr(aDatabase.table("table1").column("column1"));

See also

RWDBSimpleCaseExpr is a special case of RWDBExpr. See RWDBExpr for more details.

Example

In this example, an RWDBSimpleCaseExpr is constructed with an input expression. The instance adds several WHEN expressions and an ELSE expression, then is finally inserted into the SELECT list.

// SELECT c1,
// (CASE c2
//   WHEN 'NameA' THEN c1 * 2
//   WHEN 'NameB' THEN c1 * 5
//   ELSE c1 * 10
// END)
// FROM table1
// ORDER BY c2
 
// Instantiate a table object to represent the table.
RWDBTable t1 = aDatabase.table("table1");
 
// Instantiate a column object to represent the first column.
RWDBColumn c1 = t1["c1"];
 
// Instantiate a column object to represent the second column.
RWDBColumn c2 = t1["c2"];
 
// Instantiate simple CASE expression specifying column 2 as the input
// expression to be evaluated.
RWDBSimpleCaseExpr caseExpr(c2);
 
// Add WHEN clauses that are evaluated if column2 is equal to the
// specified WHEN expression argument.
caseExpr.when("NameA", RWDBExpr(c1) * 2);
caseExpr.when("NameB", RWDBExpr(c1) * 5);
 
// Add an ELSE expression that is evaluated if all WHEN clauses
// do not match.
caseExpr.elseExpr(c1 * 10);
 
// Instantiate a selector to represent a CASE query.
RWDBSelector aSel = db.selector();
 
// Add column 1 and the CASE expression to the SELECT list.
aSel << c1 << caseExpr;
 
// Specify an ORDER BY clause to order on column 2.
aSel.orderBy(c2);

Constructor & Destructor Documentation

RWDBSimpleCaseExpr() [1/2]

RWDBSimpleCaseExpr::RWDBSimpleCaseExpr ( const RWDBExpr & input )

explicit

Constructs an RWDBSimpleCaseExpr from input expression.

RWDBSimpleCaseExpr() [2/2]

RWDBSimpleCaseExpr::RWDBSimpleCaseExpr

(

const RWDBSimpleCaseExpr &

simpleCaseExpr

)

Copy constructor. The created RWDBSimpleCaseExpr shares an implementation with simpleCaseExpr.

Member Function Documentation

else_()

void RWDBSimpleCaseExpr::else_

(

const RWDBExpr &

elseExpr

)

Specifies the ELSE expression for self as elseExpr. If self already has an ELSE clause, this method replaces it.

operator=()

RWDBSimpleCaseExpr & RWDBSimpleCaseExpr::operator=

(

const RWDBSimpleCaseExpr &

simpleCaseExpr

)

Assignment operator. Self shares an implementation with simpleCaseExpr. Returns a reference to self.

when()

void RWDBSimpleCaseExpr::when	(	const RWDBExpr &	whenExpr,
		const RWDBExpr &	thenExpr )

Appends a WHEN/THEN clause to self where the argument whenExpr encapsulates the WHEN comparison expression, and the argument thenExpr encapsulates the THEN return expression.