ogrocidatasource.cpp

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

    if( pszDialect != NULL && EQUAL(pszDialect,"OGRSQL") )
        return OGRDataSource::ExecuteSQL( pszSQLCommand, 
                                          poSpatialFilter, 
                                          pszDialect );

/* -------------------------------------------------------------------- */
/*      Ensure any pending stuff is flushed to the database.            */
/* -------------------------------------------------------------------- */
    SyncToDisk();

/* -------------------------------------------------------------------- */
/*      Special case DELLAYER: command.                                 */
/* -------------------------------------------------------------------- */
    if( EQUALN(pszSQLCommand,"DELLAYER:",9) )
    {
        const char *pszLayerName = pszSQLCommand + 9;

        while( *pszLayerName == ' ' )
            pszLayerName++;

        DeleteLayer( pszLayerName );
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Special case VALLAYER: command.                                 */
/* -------------------------------------------------------------------- */
    if( EQUALN(pszSQLCommand,"VALLAYER:",9) )
    {
        const char *pszLayerName = pszSQLCommand + 9;

        while( *pszLayerName == ' ' )
            pszLayerName++;

        ValidateLayer( pszLayerName );
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Just execute simple command.                                    */
/* -------------------------------------------------------------------- */
    if( !EQUALN(pszSQLCommand,"SELECT",6) )
    {
        OGROCIStatement oCommand( poSession );

        oCommand.Execute( pszSQLCommand, OCI_COMMIT_ON_SUCCESS );

        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Otherwise instantiate a layer.                                  */
/* -------------------------------------------------------------------- */
    else
    {
        OGROCIStatement oCommand( poSession );
        
        if( oCommand.Execute( pszSQLCommand, OCI_DESCRIBE_ONLY ) == CE_None )
            return new OGROCISelectLayer( this, pszSQLCommand, &oCommand );
        else
            return NULL;
    }
}

/************************************************************************/
/*                          ReleaseResultSet()                          */
/************************************************************************/

void OGROCIDataSource::ReleaseResultSet( OGRLayer * poLayer )

{
    delete poLayer;
}

/************************************************************************/
/*                              FetchSRS()                              */
/*                                                                      */
/*      Return a SRS corresponding to a particular id.  Note that       */
/*      reference counting should be honoured on the returned           */
/*      OGRSpatialReference, as handles may be cached.                  */
/************************************************************************/

OGRSpatialReference *OGROCIDataSource::FetchSRS( int nId )

{
    if( nId < 0 )
        return NULL;

/* -------------------------------------------------------------------- */
/*      First, we look through our SRID cache, is it there?             */
/* -------------------------------------------------------------------- */
    int  i;

    for( i = 0; i < nKnownSRID; i++ )
    {
        if( panSRID[i] == nId )
            return papoSRS[i];
    }

/* -------------------------------------------------------------------- */
/*      Try looking up in MDSYS.CS_SRS table.                           */
/* -------------------------------------------------------------------- */
    OGROCIStatement oStatement( GetSession() );
    char            szSelect[200], **papszResult;

    sprintf( szSelect, "SELECT WKTEXT, AUTH_SRID, AUTH_NAME FROM MDSYS.CS_SRS WHERE SRID = %d", nId );

    if( oStatement.Execute( szSelect ) != CE_None )
        return NULL;

    papszResult = oStatement.SimpleFetchRow();
    if( CSLCount(papszResult) < 1 )
        return NULL;

/* -------------------------------------------------------------------- */
/*      Turn into a spatial reference.                                  */
/* -------------------------------------------------------------------- */
    char *pszWKT = papszResult[0];
    OGRSpatialReference *poSRS = NULL;

    poSRS = new OGRSpatialReference();
    if( poSRS->importFromWkt( &pszWKT ) != OGRERR_NONE )
    {
        delete poSRS;
        poSRS = NULL;
    }

/* -------------------------------------------------------------------- */
/*      If we have a corresponding EPSG code for this SRID, use that    */
/*      authority.                                                      */
/* -------------------------------------------------------------------- */
    int bGotEPSGMapping = FALSE;
    for( i = 0; anEPSGOracleMapping[i] != 0; i += 2 )
    {
        if( anEPSGOracleMapping[i] == nId )
        {
            poSRS->SetAuthority( poSRS->GetRoot()->GetValue(), "EPSG",
                                 anEPSGOracleMapping[i+1] );
            bGotEPSGMapping = TRUE;
            break;
        }
    }

/* -------------------------------------------------------------------- */
/*      Insert authority information, if it is available.               */
/* -------------------------------------------------------------------- */
    if( papszResult[1] != NULL && atoi(papszResult[1]) != 0
        && papszResult[2] != NULL && strlen(papszResult[1]) != 0 
        && poSRS->GetRoot() != NULL 
        && !bGotEPSGMapping )
    {
        poSRS->SetAuthority( poSRS->GetRoot()->GetValue(), 
                             papszResult[2], atoi(papszResult[1]) );
    }

/* -------------------------------------------------------------------- */
/*      Add to the cache.                                               */
/* -------------------------------------------------------------------- */
    panSRID = (int *) CPLRealloc(panSRID,sizeof(int) * (nKnownSRID+1) );
    papoSRS = (OGRSpatialReference **) 
        CPLRealloc(papoSRS, sizeof(void*) * (nKnownSRID + 1) );
    panSRID[nKnownSRID] = nId;
    papoSRS[nKnownSRID] = poSRS;

    nKnownSRID++;

    return poSRS;
}

/************************************************************************/
/*                             FetchSRSId()                             */
/*                                                                      */
/*      Fetch the id corresponding to an SRS, and if not found, add     */
/*      it to the table.                                                */
/************************************************************************/

int OGROCIDataSource::FetchSRSId( OGRSpatialReference * poSRS )

{
    char                *pszWKT = NULL;
    int                 nSRSId;

    if( poSRS == NULL )
        return -1;

    if( !poSRS->IsProjected() && !poSRS->IsGeographic() )
        return -1;

/* ==================================================================== */
/*      The first strategy is to see if we can identify it by           */
/*      authority information within the SRS.  Either using ORACLE      */
/*      authority values directly, or check if there is a known         */
/*      translation for an EPSG authority code.                         */
/* ==================================================================== */
    const char *pszAuthName = NULL, *pszAuthCode = NULL;

    if( poSRS->IsGeographic() )
    {
        pszAuthName = poSRS->GetAuthorityName( "GEOGCS" );
        pszAuthCode = poSRS->GetAuthorityCode( "GEOGCS" );
    }
    else if( poSRS->IsProjected() )
    {
        pszAuthName = poSRS->GetAuthorityName( "PROJCS" );
        pszAuthCode = poSRS->GetAuthorityCode( "PROJCS" );
    }

    if( pszAuthName != NULL && pszAuthCode != NULL )
    {
        if( EQUAL(pszAuthName,"Oracle") 
            && atoi(pszAuthCode) != 0 )
            return atoi(pszAuthCode);

        if( EQUAL(pszAuthName,"EPSG") )
        {
            int i, nEPSGCode = atoi(pszAuthCode);

            for( i = 0; anEPSGOracleMapping[i] != 0; i += 2 )
            {
                if( nEPSGCode == anEPSGOracleMapping[i+1] )
                    return anEPSGOracleMapping[i];
            }
        }
    }

/* ==================================================================== */
/*      We need to lookup the SRS in the existing Oracle CS_SRS         */
/*      table.                                                          */
/* ==================================================================== */

/* -------------------------------------------------------------------- */
/*      Convert SRS into old style format (SF-SQL 1.0).                 */
/* -------------------------------------------------------------------- */
    OGRSpatialReference *poSRS2 = poSRS->Clone();
    
    poSRS2->StripCTParms();

/* -------------------------------------------------------------------- */
/*      Convert any degree type unit names to "Decimal Degree".         */
/* -------------------------------------------------------------------- */
    double dfAngularUnits = poSRS2->GetAngularUnits( NULL );
    if( fabs(dfAngularUnits - 0.0174532925199433) < 0.0000000000000010 )
        poSRS2->SetAngularUnits( "Decimal Degree", 0.0174532925199433 );

/* -------------------------------------------------------------------- */
/*      Translate SRS to WKT.                                           */
/* -------------------------------------------------------------------- */
    if( poSRS2->exportToWkt( &pszWKT ) != OGRERR_NONE )
    {
        delete poSRS2;
        return -1;
    }
    
    delete poSRS2;
    
/* -------------------------------------------------------------------- */
/*      Try to find in the existing table.                              */
/* -------------------------------------------------------------------- */
    OGROCIStringBuf     oCmdText;
    OGROCIStatement     oCmdStatement( GetSession() );
    char                **papszResult = NULL;

    oCmdText.Append( "SELECT SRID FROM MDSYS.CS_SRS WHERE WKTEXT = '" );
    oCmdText.Append( pszWKT );
    oCmdText.Append( "'" );

    if( oCmdStatement.Execute( oCmdText.GetString() ) == CE_None )
        papszResult = oCmdStatement.SimpleFetchRow() ;

/* -------------------------------------------------------------------- */
/*      We got it!  Return it.                                          */
/* -------------------------------------------------------------------- */
    if( CSLCount(papszResult) == 1 )
    {
        CPLFree( pszWKT );
        return atoi( papszResult[0] );
    }
    
/* ==================================================================== */
/*      We didn't find it, so we need to define it as a new SRID at     */
/*      the end of the list of known values.                            */
/* ==================================================================== */

/* -------------------------------------------------------------------- */
/*      Get the current maximum srid in the srs table.                  */
/* -------------------------------------------------------------------- */
    if( oCmdStatement.Execute("SELECT MAX(SRID) FROM MDSYS.CS_SRS") == CE_None )
        papszResult = oCmdStatement.SimpleFetchRow();
    else
        papszResult = NULL;
        
    if( CSLCount(papszResult) == 1 )
        nSRSId = atoi(papszResult[0]) + 1;
    else
        nSRSId = 1;

/* -------------------------------------------------------------------- */
/*      Try adding the SRS to the SRS table.                            */
/* -------------------------------------------------------------------- */
    oCmdText.Clear();
    oCmdText.Append( "INSERT INTO MDSYS.CS_SRS (SRID, WKTEXT, CS_NAME) " );
    oCmdText.Appendf( 100, " VALUES (%d,'", nSRSId );
    oCmdText.Append( pszWKT );
    oCmdText.Append( "', '" );
    oCmdText.Append( poSRS->GetRoot()->GetChild(0)->GetValue() );
    oCmdText.Append( "' )" );

    CPLFree( pszWKT );

    if( oCmdStatement.Execute( oCmdText.GetString() ) != CE_None )
        return -1;
    else
        return nSRSId;
}