ibis::table::cursor Class Reference

Cursor class for row-wise data accesses. More...

#include <table.h>

Inherited by ibis::bord::cursor, ibis::mensa::cursor, ibis::tabele::cursor, and ibis::tabula::cursor.

List of all members.

Public Member Functions
virtual ibis::table::stringList	columnNames () const =0
virtual ibis::table::typeList	columnTypes () const =0
virtual int	dump (std::ostream &out, const char *del=", ") const =0
	Print out the values of the current row.
virtual int	fetch (uint64_t rownum, ibis::table::row &)=0
	Fetch the content of the specified row and make that row the current row as well.
virtual int	fetch (ibis::table::row &)=0
	Fetch the content of the next row and make the next row as the current row as well.
virtual int	fetch (uint64_t rownum)=0
	Make the specified row in the data set available for retrieval.
virtual int	fetch ()=0
	Make the next row of the data set available for retrieval.
virtual int	getColumnAsByte (size_t cnum, char *val) const =0
	This version of getColumnAsTTT directly use the column number, i.e., the position of a column in the list returned by function columnNames or columnTypes.
virtual int	getColumnAsByte (const char *cname, char *) const =0
	Retrieve the value of the named column.
virtual int	getColumnAsDouble (size_t cnum, double *val) const =0
virtual int	getColumnAsDouble (const char *cname, double *) const =0
virtual int	getColumnAsFloat (size_t cnum, float *val) const =0
virtual int	getColumnAsFloat (const char *cname, float *) const =0
virtual int	getColumnAsInt (size_t cnum, int32_t *val) const =0
virtual int	getColumnAsInt (const char *cname, int32_t *) const =0
virtual int	getColumnAsLong (size_t cnum, int64_t *val) const =0
virtual int	getColumnAsLong (const char *cname, int64_t *) const =0
virtual int	getColumnAsShort (size_t cnum, int16_t *val) const =0
virtual int	getColumnAsShort (const char *cname, int16_t *) const =0
virtual int	getColumnAsString (size_t cnum, std::string &val) const =0
virtual int	getColumnAsString (const char *cname, std::string &) const =0
virtual int	getColumnAsUByte (size_t cnum, unsigned char *val) const =0
virtual int	getColumnAsUByte (const char *cname, unsigned char *) const =0
virtual int	getColumnAsUInt (size_t cnum, uint32_t *val) const =0
virtual int	getColumnAsUInt (const char *cname, uint32_t *) const =0
virtual int	getColumnAsULong (size_t cnum, uint64_t *val) const =0
virtual int	getColumnAsULong (const char *cname, uint64_t *) const =0
virtual int	getColumnAsUShort (size_t cnum, uint16_t *val) const =0
virtual int	getColumnAsUShort (const char *cname, uint16_t *) const =0
virtual uint64_t	getCurrentRowNumber () const =0
	Return the current row number.
virtual size_t	nColumns () const =0
virtual uint64_t	nRows () const =0
Protected Member Functions
	cursor (const cursor &)
cursor &	operator= (const cursor &)

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Detailed Description

Cursor class for row-wise data accesses.

Note:

Note that this cursor is associated with a table object and can only iterate overall rows of a table. To iterate an arbitrary selection of rows, use the select function to create a new table and then iterate over the new table.

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Member Function Documentation

virtual int ibis::table::cursor::fetch	(	uint64_t	rownum,
		ibis::table::row &
	)			[pure virtual]

Fetch the content of the specified row and make that row the current row as well.

virtual int ibis::table::cursor::fetch

(

ibis::table::row &

)

[pure virtual]

Fetch the content of the next row and make the next row as the current row as well.

virtual int ibis::table::cursor::fetch

(

uint64_t

rownum

)

[pure virtual]

Make the specified row in the data set available for retrieval.

Returns 0 if the specified row is found, returns a negative number to indicate error, such as rownum out of range (-1).

virtual int ibis::table::cursor::fetch

(

)

[pure virtual]

Make the next row of the data set available for retrieval.

Returns 0 if successful, returns a negative number to indicate error.

virtual int ibis::table::cursor::getColumnAsByte	(	size_t	cnum,
		char *	val
	)			const [pure virtual]

This version of getColumnAsTTT directly use the column number, i.e., the position of a column in the list returned by function columnNames or columnTypes.

This version of the data access function may be able to avoid the name lookup and reduce the execution time.

virtual int ibis::table::cursor::getColumnAsByte	(	const char *	cname,
		char *
	)			const [pure virtual]

Retrieve the value of the named column.

Note:

Note the cost of name lookup is likely to dominate the total cost of such a function.

virtual uint64_t ibis::table::cursor::getCurrentRowNumber

(

)

const [pure virtual]

Return the current row number.

Rows in a data set are numbered [0

• nRows()-1]. If the cursor is not ready, such as before the first call to fetch or function fetch returned an error, this function return the same value as function nRows.

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

• table.h