Dv::Sql::boolexp Class Reference

An abstract base class for boolean expressions. More...

#include <select_exp.h>

Inheritance diagram for Dv::Sql::boolexp:

Public Member Functions
virtual std::ostream &	print (std::ostream &os, const Dv::Sql::Db &db) const =0
	Print this expression on a stream, using escapes for column values.
virtual	~boolexp ()
	Destructor.
const Dv::Sql::Table::Set &	tables () const
	The set of tables involved in this expression.
std::string	from () const
	Return "from" clause corresponding to this expression.
std::string	where (const Dv::Sql::Db &db) const
	Return where clause corresponding to this epression.
std::string	from_where (Dv::Sql::Db &db, const std::string &rest="") const
	Return "from .. where .. " part of an sql select statement corresponding to this expression.
std::string	query (Dv::Sql::Table::Ref table, const std::string &rest="") const
	Return a complete select statement corresponding to this expression and a table.
Protected Member Functions
template<typename T >
void	add_table (const T &t)
	Add the table(s) mentioned in a (component) of an expression to the list of involved tables.
void	add_table (const Dv::Sql::ValueExp &e)
	Add the tables involved in a value expression to the list of involved tables.
void	add_table (const Dv::Sql::Table::Column &c)
	Add the table of this column to the list of involved tables.
void	add_table (const Dv::Sql::boolexp &c)
	Add the tables involved in an expression to the list of involved tables.
Protected Attributes
Dv::Sql::Table::Set	tables_
	Set of tables mentioned in this expression.

Detailed Description

An abstract base class for boolean expressions.

See also:: Dv::Sql::basic_boolexp; Dv::Sql::complex_boolexp; Dv::Sql::true_boolexp; Dv::Sql::SelectExp

Definition at line 91 of file select_exp.h.

Constructor & Destructor Documentation

virtual Dv::Sql::boolexp::~boolexp ( ) [inline, virtual]

Destructor.

Definition at line 101 of file select_exp.h.

Member Function Documentation

virtual std::ostream& Dv::Sql::boolexp::print	(	std::ostream &	os,
		const Dv::Sql::Db &	db
	)			const `[pure virtual]`

Print this expression on a stream, using escapes for column values.

Parameters:

	os	stream to print to
	db	whose associated escape function will be used

Returns:: os

Implemented in Dv::Sql::true_boolexp, Dv::Sql::basic_boolexp< L, R >, Dv::Sql::basic_unary_boolexp< L >, Dv::Sql::match_boolexp, and Dv::Sql::complex_boolexp.

const Dv::Sql::Table::Set& Dv::Sql::boolexp::tables ( ) const [inline]

The set of tables involved in this expression.

Returns:: the set of tables involved in this expression

Definition at line 105 of file select_exp.h.

References tables_.

std::string Dv::Sql::boolexp::from ( ) const

Return "from" clause corresponding to this expression.

Returns:

A string of the form

  from table_1 , table_2 , .. , table_n

where "from" is preceeded by a space and table_1, .. , table_n are the names of the tables mentioned in the expression.

See also:: Dv::Sql::boolexp::tables; Dv::Sql::SelectExp::from

std::string Dv::Sql::boolexp::where ( const Dv::Sql::Db & db ) const

Return where clause corresponding to this epression.

Parameters:

db

database connection (needed for DBMS-dependent escape for string values).

Returns:

a string of the form

  where condition

where "where" is preceeded by a space and condition is generated by Dv::Sql::boolexp::print.

std::string Dv::Sql::boolexp::from_where	(	Dv::Sql::Db &	db,
		const std::string &	rest = `""`
	)			const

Return "from .. where .. " part of an sql select statement corresponding to this expression.

Parameters:

	db	database connection (needed for DBMS-dependent escape for string values).
	rest	optional suffix to append to the generated string.

Returns:

the string

 from() + where() + rest

Example

 Customer::Row cust;
 ...
 Dv::Sql::SelectExp e = acct_cust.match_target(cust) 
                        && acct_cust.match() 
                        && trans_acct.match();
 Dv::Sql::Object total(db, 
              "select sum(transaction.amount) as total" + e.from_where(db));

See also:: Dv::Sql::boolexp::from; Dv::Sql::boolexp::where

std::string Dv::Sql::boolexp::query	(	Dv::Sql::Table::Ref	table,
		const std::string &	rest = `""`
	)			const

Return a complete select statement corresponding to this expression and a table.

The statement retrieves all columns (using "select distinct") of the table. If there are no tables associated with this expression, as can happen e.g. when the expression is "true", then the from clause will be "from table_name" where table_name is the name of the table parameter.

Parameters:

	table	for which the columns need to be retrieved
	rest	optional suffix for the statement.

Returns:

a full sql select statement of the form

 table->select(true) +  from() + where(table->db()) + rest

See also:: Dv::Sql::Table::select; Dv::Sql::SelectExp::from

template<typename T >

void Dv::Sql::boolexp::add_table ( const T & t ) [inline, protected]

Add the table(s) mentioned in a (component) of an expression to the list of involved tables.

Parameters:

t

expression component

See also:: Dv::Sql::boolexp::tables

Definition at line 180 of file select_exp.h.

Referenced by Dv::Sql::complex_boolexp::complex_boolexp(), and Dv::Sql::match_boolexp::match_boolexp().

void Dv::Sql::boolexp::add_table ( const Dv::Sql::ValueExp & e ) [protected]

Add the tables involved in a value expression to the list of involved tables.

See also:: Dv::Sql::ValueExp::tables; Dv::Sql::boolexp::add_table(const T&)

void Dv::Sql::boolexp::add_table ( const Dv::Sql::Table::Column & c ) [protected]

Add the table of this column to the list of involved tables.

See also:: Dv::Sql::boolexp::tables; Dv::Sql::boolexp::add_table(const T&)

void Dv::Sql::boolexp::add_table ( const Dv::Sql::boolexp & c ) [protected]

Add the tables involved in an expression to the list of involved tables.

See also:: Dv::Sql::boolexp::tables; Dv::Sql::boolexp::add_table(const T&)

Member Data Documentation

Dv::Sql::Table::Set Dv::Sql::boolexp::tables_ [protected]

Set of tables mentioned in this expression.

Definition at line 173 of file select_exp.h.

Referenced by tables().

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

select_exp.h

Dv::Sql::boolexp Class Reference

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation