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harbour-core/harbour/contrib/odbc/todbc.prg

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/*
* $Id$
*/
/*
* Harbour Project source code:
* ODBC Access Class
*
* Copyright 1999 Felipe G. Coury <fcoury@creation.com.br>
* www - http://www.harbour-project.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA (or visit the web site http://www.gnu.org/).
*
* As a special exception, the Harbour Project gives permission for
* additional uses of the text contained in its release of Harbour.
*
* The exception is that, if you link the Harbour libraries with other
* files to produce an executable, this does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* Your use of that executable is in no way restricted on account of
* linking the Harbour library code into it.
*
* This exception does not however invalidate any other reasons why
* the executable file might be covered by the GNU General Public License.
*
* This exception applies only to the code released by the Harbour
* Project under the name Harbour. If you copy code from other
* Harbour Project or Free Software Foundation releases into a copy of
* Harbour, as the General Public License permits, the exception does
* not apply to the code that you add in this way. To avoid misleading
* anyone as to the status of such modified files, you must delete
* this exception notice from them.
*
* If you write modifications of your own for Harbour, it is your choice
* whether to permit this exception to apply to your modifications.
* If you do not wish that, delete this exception notice.
*
*/
#include "hbclass.ch"
#include "common.ch"
#include "sql.ch"
*+--------------------------------------------------------------------
*+
*+ Class TODBCField
*+ Fields information collection
*+
*+--------------------------------------------------------------------
*+
CLASS TODBCField FROM HBClass
DATA FieldID
DATA FieldName
DATA DataType
DATA DataSize
DATA DataDecs
DATA AllowNull
DATA Value
METHOD New()
ENDCLASS
// New fields instance
METHOD New() CLASS TODBCField
::FieldId := - 1
::FieldName := ""
::DataType := - 1
::DataSize := - 1
::DataDecs := - 1
::AllowNull := .f.
::Value := NIL
RETURN ( Self )
/*-----------------------------------------------------------------------*/
*+--------------------------------------------------------------------
*+
*+ Class TODBC
*+ Manages ODBC access
*+
*+--------------------------------------------------------------------
*+
CLASS TODBC FROM HBClass
DATA hEnv
DATA hDbc
DATA hStmt
DATA cODBCStr
DATA cODBCRes
DATA cSQL
DATA Active
DATA Fields
DATA nEof
DATA lBof
DATA nRetCode
DATA nRecCount // number of rows in current recordset
DATA nRecNo // Current row number in current recordset
DATA lCacheRS // Do we want to cache recordset in memory
DATA aRecordSet // Array to store cached recordset
METHOD New( cODBCStr )
METHOD Destroy()
METHOD SetSQL( cSQL )
METHOD Open()
METHOD ExecSQL()
METHOD CLOSE()
METHOD LoadData()
METHOD ClearData()
METHOD FieldByName( cField )
METHOD Fetch( nFetchType, nOffSet )
METHOD Next()
METHOD Prior()
METHOD First()
METHOD last()
METHOD MoveBy( nSteps )
METHOD GoTo( nRecNo )
METHOD Skip()
METHOD Eof()
METHOD Bof()
METHOD RecCount()
METHOD Lastrec()
METHOD RecNo()
METHOD SQLErrorMessage()
ENDCLASS
METHOD SQLErrorMessage() CLASS TODBC
LOCAL cErrorClass, nType, cErrorMsg
SQLError( ::hEnv, ::hDbc, ::hStmt, @cErrorClass, @nType, @cErrorMsg )
RETURN( "Error " + cErrorClass + " - " + cErrorMsg )
// New instance of TODBC
METHOD New( cODBCStr, cUserName, cPassword, lCache ) CLASS TODBC
LOCAL xBuf
LOCAL nRet
IF cUserName != NIL
DEFAULT cPassword TO ""
ENDIF
DEFAULT lCache TO .T.
// WHILE .t.
::cODBCStr := cODBCStr
::Active := .f.
::Fields := {}
::nEof := 0
::lBof := .F.
::nRecCount := 0
::nRecNo := 0
::lCacheRS := lCache
::aRecordSet:= {}
// Allocates SQL Environment
IF ( (nRet := SQLAllocEn( @xBuf )) == SQL_SUCCESS )
::hEnv := xBuf
ELSE
::nRetCode := nRet
alert( "SQLAllocEnvironment Error" )
alert( ::SQLErrorMessage() )
// EXIT
ENDIF
SQLAllocCo( ::hEnv, @xBuf ) // Allocates SQL Connection
::hDbc := xBuf
IF cUserName == NIL
SQLDriverC( ::hDbc, ::cODBCStr, @xBuf ) // Connects to Driver
::cODBCRes := xBuf
ELSE
IF .not. ( (nRet := SQLConnect( ::hDbc, cODBCStr, cUserName, cPassword)) == SQL_SUCCESS )
//TODO: Some error here
ENDIF
ENDIF
// ENDDO
RETURN ( Self )
// Destructor for TODBC class
METHOD Destroy() CLASS TODBC
SQLDisconn( ::hDbc ) // Disconnects from Driver
SQLFreeCon( ::hDbc ) // Frees the connection
SQLFreeEnv( ::hEnv ) // Frees the environment
RETURN ( NIL )
// Sets SQL Statement
METHOD SetSQL( cSQL ) CLASS TODBC
// If the DataSet is active, close it
// before assigning new statement
IF ::Active
::Close()
ENDIF
::cSQL := cSQL
RETURN ( NIL )
// Opens a DataSet given the SQL Statement
METHOD Open() CLASS TODBC
LOCAL nRet
LOCAL nCols
LOCAL nRows
LOCAL i
LOCAL cColName
LOCAL nNameLen
LOCAL nDataType
LOCAL nColSize
LOCAL nDecimals
LOCAL nNul
LOCAL xBuf
LOCAL nResult
LOCAL aCurRow
WHILE .T.
// Dataset must be closed
IF ::Active
// TODO: Some error here
// Cannot do this operation on an opened dataset
nRet := - 1
EXIT
ENDIF
// SQL statement is mandatory
IF empty( ::cSQL )
// TODO: Some error here
// SQL Statement not defined
nRet := - 1
EXIT
ENDIF
// Allocates and executes the statement
xBuf := ::hStmt
SQLAllocSt( ::hDbc, @xBuf )
::hStmt := xBuf
nRet := SQLExecDir( ::hStmt, ::cSQL )
// Get result information about fields and stores it
// on Fields collection
SQLNumRes( ::hStmt, @nCols )
// Get number of rows in result set
nResult := SQLRowCoun(::hStmt, @nRows )
if nResult == SQL_SUCCESS
::nRecCount := nRows
endif
::Fields := {}
FOR i := 1 TO nCols
SQLDescrib( ::hStmt, i, @cColName, 255, @nNameLen, @nDataType, ;
@ nColSize, @nDecimals, @nNul )
aadd( ::Fields, TODBCField():New() )
::Fields[ len( ::Fields ) ] :FieldID := i
::Fields[ len( ::Fields ) ] :FieldName := cColName
::Fields[ len( ::Fields ) ] :DataSize := nColSize
::Fields[ len( ::Fields ) ] :DataType := nDataType
::Fields[ len( ::Fields ) ] :DataDecs := nDecimals
::Fields[ len( ::Fields ) ] :AllowNull := ( nNul != 0 )
NEXT
// Do we cache recordset?
IF ::lCacheRS
::aRecordSet:={}
WHILE ::Fetch( SQL_FETCH_NEXT, 1 ) == SQL_SUCCESS
aCurRow :={}
FOR i := 1 TO nCols
aadd(aCurRow,::Fields[i]:value)
NEXT
aadd(::aRecordSet,aCurRow)
END
::nRecCount := len(::aRecordSet)
ENDIF
// Newly opened recordset - we are on first row
::nRecNo := 1
// Sets the Dataset state to active
::Active := .t.
// Put data in fields array
::LoadData(::nRecNo)
EXIT
ENDDO
RETURN ( ( nRet == 0 ) )
// Only executes the SQL Statement
METHOD ExecSQL() CLASS TODBC
LOCAL lRet
LOCAL xBuf
LOCAL nRet
WHILE .T.
// SQL statement is mandatory
IF empty( ::cSQL )
nRet := SQL_ERROR
EXIT
ENDIF
// Allocates and executes the statement
xBuf := ::hStmt
SQLAllocSt( ::hDbc, @xBuf )
::hStmt := xBuf
nRet := SQLExecDir( ::hStmt, ::cSQL )
::Close()
EXIT
ENDDO
RETURN ( nRet )
// Closes the dataset
METHOD CLOSE() CLASS TODBC
// Frees the statement
SQLFreeStm( ::hStmt, SQL_DROP )
::Active := .F.
// Reset all recordset related variables
IF ::lCacheRS
::aRecordSet:= {}
ENDIF
::nRecCount:= 0
::nRecNo := 0
::lBof := .T.
RETURN ( NIL )
// Returns the Field object for a named field
METHOD FieldByName( cField ) CLASS TODBC
LOCAL nRet := ascan( ::Fields, { | x | upper( x:FieldName ) == upper( cField ) } )
LOCAL xRet
IF nRet == 0
// TODO: Some error here
// Invalid field name
xRet := NIL
ELSE
xRet := ::Fields[ nRet ]
ENDIF
RETURN ( xRet )
// General fetch wrapper - used by next methods
METHOD Fetch( nFetchType, nOffset ) CLASS TODBC
LOCAL nRows
LOCAL nRowStatus
LOCAL nResult
LOCAL nPos:=NIL
// First clear fields
::ClearData()
// Do we have cached recordset?
IF ::lCacheRS .AND. ::Active // looks like we do ...
// Change Recno according to nFetchType and nOffset
DO CASE
CASE nFetchType == SQL_FETCH_NEXT
IF ( ::nRecNo == ::nRecCount )
nResult := SQL_NO_DATA_FOUND
ELSE
nResult := SQL_SUCCESS
nPos := ::nRecNo + 1
ENDIF
CASE nFetchType == SQL_FETCH_PRIOR
IF ( ::nRecNo == 1 )
nResult := SQL_NO_DATA_FOUND
ELSE
nResult := SQL_SUCCESS
nPos := ::nRecNo - 1
ENDIF
CASE nFetchType == SQL_FETCH_FIRST
nResult := SQL_SUCCESS
nPos := 1
CASE nFetchType == SQL_FETCH_LAST
nResult := SQL_SUCCESS
nPos := ::nRecCount
CASE nFetchType == SQL_FETCH_RELATIVE
IF ( ::nRecNo + nOffset ) > ::nRecCount .OR. ( ::nRecNo + nOffset ) < 1 // TODO: Should we go to the first/last row if out of bounds?
nResult := SQL_ERROR
ELSE
nResult := SQL_SUCCESS
nPos := ::nRecNo + nOffset
ENDIF
CASE nFetchType == SQL_FETCH_ABSOLUTE
IF nOffset > ::nRecCount .OR. nOffset < 1 // TODO: Should we go to the first/last row if out of bounds?
nResult := SQL_ERROR
ELSE
nResult := SQL_SUCCESS
nPos := nOffset
ENDIF
OTHERWISE
nResult := SQL_ERROR
ENDCASE
ELSE // apearently we don't have
nResult := SQLFetchSc( ::hStmt, nFetchType, nOffSet )
ENDIF
IF nResult==SQL_SUCCESS
::LoadData(nPos)
::lBof := .F.
ELSE
// TODO: Report error here
ENDIF
RETURN ( nResult )
// Moves to next record on DataSet
METHOD NEXT () CLASS TODBC
LOCAL nResult
nResult := ::Fetch( SQL_FETCH_NEXT, 1 )
if nResult == SQL_SUCCESS
::nRecno := ::nRecno + 1
elseif ( nResult == SQL_NO_DATA_FOUND ) .AND. ( ::nRecNo==::nRecCount ) // permit skip on last row, so that EOF() can work properly
::nRecno := ::nRecno + 1
else
//TODO: Error handling
endif
RETURN ( nResult )
// Moves to prior record on DataSet
METHOD Prior() CLASS TODBC
LOCAL nResult
nResult := ::Fetch( SQL_FETCH_PRIOR, 1 )
if nResult == SQL_SUCCESS
::nRecno := ::nRecno - 1
elseif ( nResult == SQL_NO_DATA_FOUND ) .AND. ( ::nRecNo==1 ) // permit skip-1 on first row, so that BOF() can work properly
::nRecno := ::nRecno - 1
::next()
::lBof := .T.
else
//TODO: Error handling
endif
RETURN ( nResult )
// Moves to first record on DataSet
METHOD First() CLASS TODBC
LOCAL nResult
nResult := ::Fetch( SQL_FETCH_FIRST, 1 )
if nResult == SQL_SUCCESS
::nRecno := 1
else
//TODO: Error handling
endif
RETURN ( nResult )
// Moves to the last record on DataSet
METHOD last() CLASS TODBC
LOCAL nResult
nResult := ::Fetch( SQL_FETCH_LAST, 1 )
if nResult == SQL_SUCCESS
::nRecno := ::nRecCount
else
//TODO: Error handling
endif
RETURN ( nResult )
// Moves the DataSet nSteps from the current record
METHOD MoveBy( nSteps ) CLASS TODBC
LOCAL nResult
//TODO: Check if nSteps goes beyond eof
nResult := ::Fetch( SQL_FETCH_RELATIVE, nSteps )
if nResult == SQL_SUCCESS
::nRecno := ::nRecNo + nSteps
else
//TODO: Error handling
endif
RETURN ( nResult )
// Moves the DataSet to absolute record number
METHOD GOTO( nRecNo ) CLASS TODBC
LOCAL nResult
nResult := ::Fetch( SQL_FETCH_ABSOLUTE, nRecNo )
if nResult == SQL_SUCCESS
::nRecno := nRecNo
else
//TODO: Error handling
endif
RETURN ( nResult )
// Skips dataset to the next record - wrapper to Next()
METHOD SKIP() CLASS TODBC
RETURN ( ::Next() )
// Checks for End of File (End of DataSet, actually)
// NOTE: Current implementation usable only with drivers that report number of records in last select
METHOD eof() CLASS TODBC
LOCAL lResult := .F.
// Do we have any data in recordset?
if ::nRecCount > 0
lResult := ( ::nRecNo > ::nRecCount )
else
lResult := .T.
endif
RETURN ( lResult )
// Checks for Begining of File
METHOD bof() CLASS TODBC
RETURN ( ::lBof )
// Returns the current row in dataset
METHOD RecNo() CLASS TODBC
RETURN ( ::nRecNo )
// Returns number of rows ( if that function is supported by ODBC driver )
METHOD Lastrec() CLASS TODBC
RETURN ( ::nRecCount )
// Returns number of rows ( if that function is supported by ODBC driver )
METHOD RecCount() CLASS TODBC
RETURN ( ::nRecCount )
// Loads current record data into the Fields collection
METHOD LoadData(nPos) CLASS TODBC
LOCAL xRet
LOCAL i
FOR i := 1 TO len( ::Fields )
xRet := space( 128 )
IF ::lCacheRS .AND. ::Active
IF nPos > 0 .and. nPos <= ::nRecCount
xRet := ::aRecordSet[ nPos,i ]
ENDIF
ELSE
SQLGetData( ::hStmt, ::Fields[ i ] :FieldID, SQL_CHAR, len( xRet ), @xRet )
ENDIF
::Fields[ i ] :Value := xRet
NEXT
RETURN ( NIL )
// Clears the Fields collection
METHOD ClearData() CLASS TODBC
LOCAL i
FOR i := 1 TO len( ::Fields )
::Fields[ i ] :Value := NIL
NEXT
RETURN ( NIL )
*+ EOF: TODBC.PRG