Select Class Reference

#include <select.h>

Inheritance diagram for Select:

Collaboration diagram for Select:

Public Member Functions
	Select (FileId rel_id, FileId result_id, std::vector< FieldId > fields, std::vector< Comp > comps, std::vector< void * > values, Catalog *catalog)
	Constructor for Select operation. Both FileScan and IndexScan use this constructor.
	~Select ()
	Destructor for the Select Operation.
Public Member Functions inherited from Operation
	Operation (FileId result_id, Catalog *catalog)
	Constructor for the Operation class. Because Operation is an abstract class, an object cannot be created, but this constructor is used by derived classes.
virtual	~Operation ()
	Destructor for the Operation class. Cleans up dynamic memory in result state.
virtual void	runOperation ()=0
	Runs the operation. Other than initial setup in the initialization, all the work of each operation is done in this function. It is a pure virtual method, and is implemented in inherited classes. All child classes must implement this method.

Protected Attributes
std::vector< FieldId >	fields
std::vector< Comp >	comps
std::vector< void * >	values
fileState	file_state
Protected Attributes inherited from Operation
fileState	result_state
Catalog *	catalog

Additional Inherited Members
Protected Member Functions inherited from Operation
void	_initState (FileId file_id, std::vector< FieldId > fields, fileState *state)
	Performs the file and temporary record setup for relational operators.
void	_delState (fileState *file_state)
	Deletes objects created in relop structs.

Detailed Description

Select is an abstract class that lays the foundation for select operations

Constructor & Destructor Documentation

Select()

Select::Select	(	FileId	rel_id,
		FileId	result_id,
		std::vector< FieldId >	fields,
		std::vector< Comp >	comps,
		std::vector< void * >	values,
		Catalog *	catalog
	)

Constructor for Select operation. Both FileScan and IndexScan use this constructor.

Parameters

rel_id.	FileId of the relation file.
result_id.	FileId of the result file.
fields.	Vector of field ids for the select operation.
comps.	Vector of Comps for the select operation.
values.	Vector of Void * for the select operation.
catalog.	pointer to the catalog of SwatDB

Precondition

file_name is the name of a valid file.

Postcondition

private variables have been set accordingly.

Member Data Documentation

comps

std::vector<Comp> Select::comps

protected

comparators used in the select operation

fields

std::vector<FieldId> Select::fields

protected

The positions of the following three vectors are lined up, so index 0 of each are one conjunct of the select, index 1 is the next, and so on. Fields used in the select operation

values

std::vector<void *> Select::values

protected

Values used in the select operation. Type is void * because this could be a mix of float, int, and char * types.

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

• select.h