isc::db::PgSqlResult Class Reference

RAII wrapper for PostgreSQL Result sets. More...

#include <pgsql_exchange.h>

Inheritance diagram for isc::db::PgSqlResult:

Public Member Functions
	PgSqlResult (PGresult *result)
	Constructor.
	~PgSqlResult ()
	Destructor.
void	colCheck (int col) const
	Determines if a column index is valid.
int	getCols () const
	Returns the number of columns in the result set.
std::string	getColumnLabel (const int col) const
	Fetches the name of the column in a result set.
int	getRows () const
	Returns the number of rows in the result set.
	operator bool () const
	Boolean Operator.
	operator PGresult * () const
	Conversion Operator.
void	rowCheck (int row) const
	Determines if a row index is valid.
void	rowColCheck (int row, int col) const
	Determines if both a row and column index are valid.

Detailed Description

RAII wrapper for PostgreSQL Result sets.

When a Postgresql statement is executed, the results are returned in a pointer allocated structure, PGresult*. Data and status information are accessed via calls to functions such as PQgetvalue() which require the results pointer. In order to ensure this structure is freed, any invocation of Psql function which returns a PGresult* (e.g. PQexec, PQExecPrepared, ...) must save the result to an instance of this class. Example: {{{ PgSqlResult r(PQexec(conn_, "ROLLBACK")); }}}

This eliminates the need for an explicit release via, PQclear() and guarantees that the resources are released even if the an exception is thrown.

Definition at line 46 of file pgsql_exchange.h.

Constructor & Destructor Documentation

PgSqlResult()

isc::db::PgSqlResult::PgSqlResult

(

PGresult *

result

)

Constructor.

Store the pointer to the fetched result set. Set row and column counts for convenience.

Parameters

result

pointer to the Postgresql client layer result If the value of is NULL, row and col values will be set to -1. This allows PgSqlResult to be passed into statement error checking.

Definition at line 56 of file pgsql_connection.cc.

~PgSqlResult()

isc::db::PgSqlResult::~PgSqlResult

(

)

Destructor.

Frees the result set

Definition at line 79 of file pgsql_connection.cc.

Member Function Documentation

colCheck()

void isc::db::PgSqlResult::colCheck

(

int

col

)

const

Determines if a column index is valid.

Parameters

col	index to range check

Exceptions

DbOperationError

if the column index is out of range

Definition at line 86 of file pgsql_connection.cc.

References isc_throw.

Referenced by getColumnLabel(), and rowColCheck().

getCols()

int isc::db::PgSqlResult::getCols ( ) const

inline

Returns the number of columns in the result set.

Definition at line 70 of file pgsql_exchange.h.

getColumnLabel()

std::string isc::db::PgSqlResult::getColumnLabel

(

const int

col

)

const

Fetches the name of the column in a result set.

Returns the column name of the column from the result set. If the column index is out of range it will return the string "Unknown column:<index>"

Parameters

col	index of the column name to fetch

Returns

string containing the name of the column This method is exception safe.

Definition at line 100 of file pgsql_connection.cc.

References colCheck().

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getRows()

int isc::db::PgSqlResult::getRows ( ) const

inline

Returns the number of rows in the result set.

Definition at line 65 of file pgsql_exchange.h.

operator bool()

isc::db::PgSqlResult::operator bool ( ) const

inline

Boolean Operator.

Allows testing the PgSqlResult object for emptiness: "if (result)"

Definition at line 119 of file pgsql_exchange.h.

operator PGresult *()

isc::db::PgSqlResult::operator PGresult * ( ) const

inline

Conversion Operator.

Allows the PgSqlResult object to be passed as the result set argument to PQxxxx functions.

Definition at line 112 of file pgsql_exchange.h.

rowCheck()

void isc::db::PgSqlResult::rowCheck

(

int

row

)

const

Determines if a row index is valid.

Parameters

row	index to range check

Exceptions

DbOperationError

if the row index is out of range

Definition at line 72 of file pgsql_connection.cc.

References isc_throw.

Referenced by rowColCheck().

rowColCheck()

void isc::db::PgSqlResult::rowColCheck	(	int	row,
		int	col ) const

Determines if both a row and column index are valid.

Parameters

row	index to range check
col	index to range check

Exceptions

DbOperationError

if either the row or column index is out of range

Definition at line 94 of file pgsql_connection.cc.

References colCheck(), and rowCheck().

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

• pgsql_exchange.h
• pgsql_connection.cc