Main | License | Installation | FAQ | Screenshots | Contact | Links | Sf.net | Freshmeat.net | KDE-Apps.org

MySQLStatement Class Reference
[MySQL C++ Wrappers]

#include <mysqlStatement.hpp>

Inheritance diagram for MySQLStatement:

[legend]

Public Member Functions
	MySQLStatement (MySQLDatabase *_database, const std::string &query) throw (Error)
virtual	~MySQLStatement (void)
	Destructor frees the statement handle.
virtual int	getNumCols (void) throw (Error)
virtual std::string	getColAttr (int col) throw (Error)
virtual ResultRowPtr	fetchRow (void) throw (Error)
	Fetch row of resulting row.
Protected Attributes
MySQLDatabase *	database
MYSQL_RES *	result
ResultRowPtr	resultRow

---

Detailed Description

Class for executing SQL query and querying results. Call MySQLDatabase::execQuery to acquire an instance of this class.

Date:

Thu Mar 03 2005

Author:

Jan Wedekind (wedesoft@users.sourceforge.net)

Definition at line 30 of file mysqlStatement.hpp.

---

Constructor & Destructor Documentation

MySQLStatement::MySQLStatement	(	MySQLDatabase *	_database,
		const std::string &	query
	)			throw (Error)

Constructor requiring MySQL handle. Call MySQLDatabase::execQuery to acquire an instance of this class.

See also:

MySQLDatabase::execQuery

Definition at line 22 of file mysqlStatement.cpp.

References ERRORMACRO.

               :
  database( _database ), result( NULL )
{
  if ( !query.empty() ) {
#ifndef NDEBUG
    // cerr << query << endl;
#endif
    // Apparently a trailing semicolon doesn't cause any problems.
    ERRORMACRO( mysql_real_query( database->getConnection(), query.c_str(),
                                  query.size() ) == 0,
                Error, , "Error executing query '" << query << "': "
                << mysql_error( database->getConnection() ) );

    // Retrieve column-information, if applicable.
    if ( getNumCols() > 0 ) {
      result = mysql_use_result( database->getConnection() );
      ERRORMACRO( result != NULL, Error, ,
                  "Error retrieving column-information: "
                  << mysql_error( database->getConnection() ) );
    };
  } else
    database = NULL;
}

MySQLStatement::~MySQLStatement

(

void

)

[virtual]

Destructor frees the statement handle.

Definition at line 48 of file mysqlStatement.cpp.

References result, and resultRow.

{

  if ( resultRow )
    resultRow->invalidate();

  if ( result != NULL ) {

    // Purge remaining data (see mysql-documentation!).
    while ( mysql_fetch_row( result ) );
    mysql_free_result( result );

  };

}

---

Member Function Documentation

int MySQLStatement::getNumCols

(

void

)

throw (Error) [virtual]

Get number of result columns.

Returns:

Number of resulting columns of a SELECT query. 0 if there is none.

Implements Statement.

Definition at line 64 of file mysqlStatement.cpp.

References database, and MySQLDatabase::getConnection().

Referenced by getColAttr().

{
  int retVal;
  if ( database != NULL )
    retVal = mysql_field_count( database->getConnection() );
  else
    retVal = 0;
  return retVal;
}

std::string MySQLStatement::getColAttr

(

int

col

)

throw (Error) [virtual]

Meta information about column.

Parameters:

col

Number of column (between 0 and getNumCols()-1).

Implements Statement.

Definition at line 74 of file mysqlStatement.cpp.

References ERRORMACRO, getNumCols(), and result.

{
  ERRORMACRO( col >= 0 && col < getNumCols(), Error, ,
              "Column number of meta-column must be between 0 and "
              << ( getNumCols() - 1 ) << " but was " << col << "." );

  assert( result != NULL );
  mysql_field_seek( result, col );
  return mysql_fetch_field( result )->name;
}

ResultRowPtr MySQLStatement::fetchRow

(

void

)

throw (Error) [virtual]

Fetch row of resulting row.

Implements Statement.

Definition at line 85 of file mysqlStatement.cpp.

References ERRORMACRO, result, and resultRow.

{
  assert( result != NULL );

  if ( resultRow ) {
    ERRORMACRO( resultRow.use_count() <= 1, Error, ,
                "Can not fetch new row, "
                "because previous row was not released yet." );
    assert( resultRow.use_count() == 1 );
  };

  MYSQL_ROW row = mysql_fetch_row( result );
  if ( row != NULL )
    resultRow = ResultRowPtr( new MySQLResultRow( row ) );
  else
    resultRow.reset();

  return resultRow;
}

---

Field Documentation

MySQLDatabase* MySQLStatement::database [protected]

Definition at line 48 of file mysqlStatement.hpp.

Referenced by getNumCols().

MYSQL_RES* MySQLStatement::result [protected]

Definition at line 50 of file mysqlStatement.hpp.

Referenced by fetchRow(), getColAttr(), and ~MySQLStatement().

ResultRowPtr MySQLStatement::resultRow [protected]

Definition at line 52 of file mysqlStatement.hpp.

Referenced by fetchRow(), and ~MySQLStatement().

---

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

• mysqlStatement.hpp
• mysqlStatement.cpp

---