ogrocitablelayer.cpp

来自「支持各种栅格图像和矢量图像读取的库」· C++ 代码 · 共 1,710 行 · 第 1/5 页

/************************************************************************/
/*                      BuildFullQueryStatement()                       */
/************************************************************************/

void OGROCITableLayer::BuildFullQueryStatement()

{
    if( pszQueryStatement != NULL )
    {
        CPLFree( pszQueryStatement );
        pszQueryStatement = NULL;
    }

    OGROCIStringBuf oCmd;
    char *pszFields = BuildFields();

    oCmd.Append( "SELECT " );
    oCmd.Append( pszFields );
    oCmd.Append( " FROM " );
    oCmd.Append( poFeatureDefn->GetName() );
    oCmd.Append( " " );
    oCmd.Append( pszWHERE );

    pszQueryStatement = oCmd.StealString();

    CPLFree( pszFields );
}

/************************************************************************/
/*                             GetFeature()                             */
/************************************************************************/

OGRFeature *OGROCITableLayer::GetFeature( long nFeatureId )

{

/* -------------------------------------------------------------------- */
/*      If we don't have an FID column scan for the desired feature.    */
/* -------------------------------------------------------------------- */
    if( pszFIDName == NULL )
        return OGROCILayer::GetFeature( nFeatureId );

/* -------------------------------------------------------------------- */
/*      Clear any existing query.                                       */
/* -------------------------------------------------------------------- */
    ResetReading();

/* -------------------------------------------------------------------- */
/*      Build query for this specific feature.                          */
/* -------------------------------------------------------------------- */
    OGROCIStringBuf oCmd;
    char *pszFields = BuildFields();

    oCmd.Append( "SELECT " );
    oCmd.Append( pszFields );
    oCmd.Append( " FROM " );
    oCmd.Append( poFeatureDefn->GetName() );
    oCmd.Append( " " );
    oCmd.Appendf( 50+strlen(pszFIDName), 
                  " WHERE \"%s\" = %ld ", 
                  pszFIDName, nFeatureId );

/* -------------------------------------------------------------------- */
/*      Execute the statement.                                          */
/* -------------------------------------------------------------------- */
    if( !ExecuteQuery( oCmd.GetString() ) )
        return NULL;

/* -------------------------------------------------------------------- */
/*      Get the feature.                                                */
/* -------------------------------------------------------------------- */
    OGRFeature *poFeature;

    poFeature = GetNextRawFeature();
    
    if( poFeature != NULL && poFeature->GetGeometryRef() != NULL )
        poFeature->GetGeometryRef()->assignSpatialReference( poSRS );

/* -------------------------------------------------------------------- */
/*      Cleanup the statement.                                          */
/* -------------------------------------------------------------------- */
    ResetReading();

/* -------------------------------------------------------------------- */
/*      verify the FID.                                                 */
/* -------------------------------------------------------------------- */
    if( poFeature != NULL && poFeature->GetFID() != nFeatureId )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "OGROCITableLayer::GetFeature(%d) ... query returned feature %d instead!",
                  nFeatureId, poFeature->GetFID() );
        delete poFeature;
        return NULL;
    }
    else
        return poFeature;
}

/************************************************************************/
/*                           GetNextFeature()                           */
/*                                                                      */
/*      We override the next feature method because we know that we     */
/*      implement the attribute query within the statement and so we    */
/*      don't have to test here.   Eventually the spatial query will    */
/*      be fully tested within the statement as well.                   */
/************************************************************************/

OGRFeature *OGROCITableLayer::GetNextFeature()

{

    for( ; TRUE; )
    {
        OGRFeature      *poFeature;

        poFeature = GetNextRawFeature();
        if( poFeature == NULL )
        {
            CPLDebug( "OCI", "Query complete, got %d hits, and %d discards.",
                      nHits, nDiscarded );
            nHits = 0;
            nDiscarded = 0;
            return NULL;
        }

        if( m_poFilterGeom == NULL
            || FilterGeometry( poFeature->GetGeometryRef() ) )
        {
            nHits++;
            if( poFeature->GetGeometryRef() != NULL )
                poFeature->GetGeometryRef()->assignSpatialReference( poSRS );
            return poFeature;
        }

        if( m_poFilterGeom != NULL )
            nDiscarded++;

        delete poFeature;
    }
}

/************************************************************************/
/*                            ResetReading()                            */
/************************************************************************/

void OGROCITableLayer::ResetReading()

{
    nHits = 0;
    nDiscarded = 0;

    FlushPendingFeatures();

    BuildFullQueryStatement();

    OGROCILayer::ResetReading();
}

/************************************************************************/
/*                            BuildFields()                             */
/*                                                                      */
/*      Build list of fields to fetch, performing any required          */
/*      transformations (such as on geometry).                          */
/************************************************************************/

char *OGROCITableLayer::BuildFields()

{
    int         i;
    OGROCIStringBuf oFldList;

    if( pszGeomName )                                                   
    {
        oFldList.Append( "\"" );
        oFldList.Append( pszGeomName );
        oFldList.Append( "\"" );
        iGeomColumn = 0;
    }

    for( i = 0; i < poFeatureDefn->GetFieldCount(); i++ )
    {
        const char *pszName = poFeatureDefn->GetFieldDefn(i)->GetNameRef();

        if( oFldList.GetLast() != '\0' )
            oFldList.Append( "," );

        oFldList.Append( "\"" );
        oFldList.Append( pszName );
        oFldList.Append( "\"" );
    }

    if( pszFIDName != NULL )
    {
        iFIDColumn = poFeatureDefn->GetFieldCount();
        oFldList.Append( ",\"" );
        oFldList.Append( pszFIDName );
        oFldList.Append( "\"" );
    }

    return oFldList.StealString();
}

/************************************************************************/
/*                         SetAttributeFilter()                         */
/************************************************************************/

OGRErr OGROCITableLayer::SetAttributeFilter( const char *pszQuery )

{
    if( (pszQuery == NULL && this->pszQuery == NULL)
        || (pszQuery != NULL && this->pszQuery != NULL
            && strcmp(pszQuery,this->pszQuery) == 0) )
        return OGRERR_NONE;
    
    CPLFree( this->pszQuery );

    if( pszQuery == NULL )
        this->pszQuery = NULL;
    else
        this->pszQuery = CPLStrdup( pszQuery );

    BuildWhere();

    ResetReading();

    return OGRERR_NONE;
}

/************************************************************************/
/*                             SetFeature()                             */
/*                                                                      */
/*      We implement SetFeature() by deleting the existing row (if      */
/*      it exists), and then using CreateFeature() to write it out      */
/*      tot he table normally.  CreateFeature() will preserve the       */
/*      existing FID if possible.                                       */
/************************************************************************/

OGRErr OGROCITableLayer::SetFeature( OGRFeature *poFeature )

{
/* -------------------------------------------------------------------- */
/*      Do some validation.                                             */
/* -------------------------------------------------------------------- */
    if( pszFIDName == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "OGROCITableLayer::SetFeature(%d) failed because there is "
                  "no apparent FID column on table %s.",
                  poFeature->GetFID(), 
                  poFeatureDefn->GetName() );

        return OGRERR_FAILURE;
    }

    if( poFeature->GetFID() == OGRNullFID )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "OGROCITableLayer::SetFeature(%d) failed because the feature "
                  "has no FID!", poFeature->GetFID() );

        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Prepare the delete command, and execute.  We don't check the    */
/*      error result of the execute, since attempting to Set a          */
/*      non-existing feature may be OK.                                 */
/* -------------------------------------------------------------------- */
    OGROCIStringBuf     oCmdText;
    OGROCIStatement     oCmdStatement( poDS->GetSession() );

    oCmdText.Appendf( strlen(poFeatureDefn->GetName())+strlen(pszFIDName)+100,
                      "DELETE FROM %s WHERE \"%s\" = %d",
                      poFeatureDefn->GetName(), 
                      pszFIDName, 
                      poFeature->GetFID() );

    oCmdStatement.Execute( oCmdText.GetString() );

    return CreateFeature( poFeature );
}

/************************************************************************/
/*                           DeleteFeature()                            */
/************************************************************************/

OGRErr OGROCITableLayer::DeleteFeature( long nFID )

{
/* -------------------------------------------------------------------- */
/*      Do some validation.                                             */
/* -------------------------------------------------------------------- */
    if( pszFIDName == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "OGROCITableLayer::DeleteFeature(%d) failed because there is "
                  "no apparent FID column on table %s.",
                  nFID, 
                  poFeatureDefn->GetName() );

        return OGRERR_FAILURE;
    }

    if( nFID == OGRNullFID )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "OGROCITableLayer::DeleteFeature(%d) failed for Null FID", 
                  nFID );

        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Prepare the delete command, and execute.  We don't check the    */
/*      error result of the execute, since attempting to Set a          */
/*      non-existing feature may be OK.                                 */
/* -------------------------------------------------------------------- */
    OGROCIStringBuf     oCmdText;
    OGROCIStatement     oCmdStatement( poDS->GetSession() );

    oCmdText.Appendf( strlen(poFeatureDefn->GetName())+strlen(pszFIDName)+100,
                      "DELETE FROM %s WHERE \"%s\" = %d",
                      poFeatureDefn->GetName(), 
                      pszFIDName, 
                      nFID );

    if( oCmdStatement.Execute( oCmdText.GetString() ) == CE_None )
        return OGRERR_NONE;
    else
        return OGRERR_FAILURE;
}

/************************************************************************/
/*                           CreateFeature()                            */
/************************************************************************/

OGRErr OGROCITableLayer::CreateFeature( OGRFeature *poFeature )

{
/* -------------------------------------------------------------------- */
/*      Add extents of this geometry to the existing layer extents.     */