ogrmysqltablelayer.cpp

来自「支持各种栅格图像和矢量图像读取的库」· C++ 代码 · 共 1,065 行 · 第 1/3 页

            poDefn->SetGeomType( nGeomType );

        } 

        if( hResult != NULL )
            mysql_free_result( hResult );   //Free our query results for finding type.
			hResult = NULL;
    } 
 
    // Fetch the SRID for this table now
    nSRSId = FetchSRSId(); 
    return poDefn;
}

/************************************************************************/
/*                          SetSpatialFilter()                          */
/************************************************************************/

void OGRMySQLTableLayer::SetSpatialFilter( OGRGeometry * poGeomIn )

{
    if( !InstallFilter( poGeomIn ) )
        return;

    BuildWhere();

    ResetReading();
}



/************************************************************************/
/*                             BuildWhere()                             */
/*                                                                      */
/*      Build the WHERE statement appropriate to the current set of     */
/*      criteria (spatial and attribute queries).                       */
/************************************************************************/

void OGRMySQLTableLayer::BuildWhere()

{
    char        szWHERE[4096];
    
    CPLFree( pszWHERE );
    pszWHERE = NULL;

    szWHERE[0] = '\0';

    if( m_poFilterGeom != NULL && pszGeomColumn )
    {
        char szEnvelope[4096];
        OGREnvelope  sEnvelope;
        szEnvelope[0] = '\0';
        
        //POLYGON((MINX MINY, MAXX MINY, MAXX MAXY, MINX MAXY, MINX MINY))
        m_poFilterGeom->getEnvelope( &sEnvelope );
        
        sprintf(szEnvelope,
                "POLYGON((%.12f %.12f, %.12f %.12f, %.12f %.12f, %.12f %.12f, %.12f %.12f))",
                sEnvelope.MinX, sEnvelope.MinY,
                sEnvelope.MaxX, sEnvelope.MinY,
                sEnvelope.MaxX, sEnvelope.MaxY,
                sEnvelope.MinX, sEnvelope.MaxY,
                sEnvelope.MinX, sEnvelope.MinY);

        sprintf( szWHERE,
                 "WHERE MBRIntersects(GeomFromText('%s'), %s)",
                 szEnvelope,
                 pszGeomColumn);

    }

    if( pszQuery != NULL )
    {
        if( strlen(szWHERE) == 0 )
            sprintf( szWHERE, "WHERE %s ", pszQuery  );
        else
            sprintf( szWHERE+strlen(szWHERE), "&& %s ", pszQuery );
    }

    pszWHERE = CPLStrdup(szWHERE);
}

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

void OGRMySQLTableLayer::BuildFullQueryStatement()

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

    char *pszFields = BuildFields();

    pszQueryStatement = (char *) 
        CPLMalloc(strlen(pszFields)+strlen(pszWHERE)
                  +strlen(poFeatureDefn->GetName()) + 40);
    sprintf( pszQueryStatement,
             "SELECT %s FROM %s %s", 
             pszFields, poFeatureDefn->GetName(), pszWHERE );
    
    CPLFree( pszFields );
}

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

void OGRMySQLTableLayer::ResetReading()

{
    BuildFullQueryStatement();

    OGRMySQLLayer::ResetReading();
}

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

char *OGRMySQLTableLayer::BuildFields()

{
    int         i, nSize;
    char        *pszFieldList;

    nSize = 25;
    if( pszGeomColumn )
        nSize += strlen(pszGeomColumn);

    if( bHasFid )
        nSize += strlen(pszFIDColumn);
        

    for( i = 0; i < poFeatureDefn->GetFieldCount(); i++ )
        nSize += strlen(poFeatureDefn->GetFieldDefn(i)->GetNameRef()) + 4;

    pszFieldList = (char *) CPLMalloc(nSize);
    pszFieldList[0] = '\0';

    if( bHasFid && poFeatureDefn->GetFieldIndex( pszFIDColumn ) == -1 )
        sprintf( pszFieldList, "%s", pszFIDColumn );

    if( pszGeomColumn )
    {
        if( strlen(pszFieldList) > 0 )
            strcat( pszFieldList, ", " );

		/* ------------------------------------------------------------ */
		/*      Geometry returned from MySQL is as WKB, with the        */
        /*      first 4 bytes being an int that defines the SRID        */
        /*      and the rest being the WKB.                             */
		/* ------------------------------------------------------------ */            
        sprintf( pszFieldList+strlen(pszFieldList), 
                 "%s %s", pszGeomColumn, pszGeomColumn );
    }

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

        if( strlen(pszFieldList) > 0 )
            strcat( pszFieldList, ", " );

        strcat( pszFieldList, pszName );
    }

    CPLAssert( (int) strlen(pszFieldList) < nSize );

    return pszFieldList;
}

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

OGRErr OGRMySQLTableLayer::SetAttributeFilter( const char *pszQuery )

{
    CPLFree( this->pszQuery );

    if( pszQuery == NULL || strlen(pszQuery) == 0 )
        this->pszQuery = NULL;
    else
        this->pszQuery = CPLStrdup( pszQuery );

    BuildWhere();

    ResetReading();

    return OGRERR_NONE;
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int OGRMySQLTableLayer::TestCapability( const char * pszCap )

{
    if( EQUAL(pszCap,OLCRandomRead) )
        return bHasFid;

    else if( EQUAL(pszCap,OLCFastFeatureCount) )
        return TRUE;

    else 
        return OGRMySQLLayer::TestCapability( pszCap );
}

/************************************************************************/
/*                             SetFeature()                             */
/*                                                                      */
/*      SetFeature() is implemented by dropping the old copy of the     */
/*      feature in question (if there is one) and then creating a       */
/*      new one with the provided feature id.                           */
/************************************************************************/

OGRErr OGRMySQLTableLayer::SetFeature( OGRFeature *poFeature )

{
    OGRErr eErr;

    if( poFeature->GetFID() == OGRNullFID )
    {
        CPLError( CE_Failure, CPLE_AppDefined,
                  "FID required on features given to SetFeature()." );
        return OGRERR_FAILURE;
    }

    eErr = DeleteFeature( poFeature->GetFID() );
    if( eErr != OGRERR_NONE )
        return eErr;

    return CreateFeature( poFeature );
}

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

OGRErr OGRMySQLTableLayer::DeleteFeature( long nFID )

{
    MYSQL_RES           *hResult=NULL;
    CPLString           osCommand;


/* -------------------------------------------------------------------- */
/*      We can only delete features if we have a well defined FID       */
/*      column to target.                                               */
/* -------------------------------------------------------------------- */
    if( !bHasFid )
    {
        CPLError( CE_Failure, CPLE_AppDefined,
                  "DeleteFeature(%d) failed.  Unable to delete features "
                  "in tables without\n a recognised FID column.",
                  nFID );
        return OGRERR_FAILURE;

    }

/* -------------------------------------------------------------------- */
/*      Form the statement to drop the record.                          */
/* -------------------------------------------------------------------- */
    osCommand.Printf( "DELETE FROM %s WHERE %s = %ld",
                      poFeatureDefn->GetName(), pszFIDColumn, nFID );
                      
/* -------------------------------------------------------------------- */
/*      Execute the delete.                                             */
/* -------------------------------------------------------------------- */
    if( mysql_query(poDS->GetConn(), osCommand.c_str() ) ){   
        poDS->ReportError(  osCommand.c_str() );
        return OGRERR_FAILURE;   
    }

    // make sure to attempt to free results of successful queries
    hResult = mysql_store_result( poDS->GetConn() );
    if( hResult != NULL )
        mysql_free_result( hResult );
    hResult = NULL;
    
    return OGRERR_NONE;
}


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

OGRErr OGRMySQLTableLayer::CreateFeature( OGRFeature *poFeature )

{
    MYSQL_RES           *hResult=NULL;
    CPLString           osCommand;
    int                 i, bNeedComma = FALSE;

/* -------------------------------------------------------------------- */
/*      Form the INSERT command.                                        */
/* -------------------------------------------------------------------- */
    osCommand.Printf( "INSERT INTO %s (", poFeatureDefn->GetName() );

    if( poFeature->GetGeometryRef() != NULL )
    {
        osCommand = osCommand + pszGeomColumn + " ";
        bNeedComma = TRUE;
    }

    if( poFeature->GetFID() != OGRNullFID && pszFIDColumn != NULL )
    {
        if( bNeedComma )
            osCommand += ", ";
        
        osCommand = osCommand + pszFIDColumn + " ";
        bNeedComma = TRUE;
    }

    for( i = 0; i < poFeatureDefn->GetFieldCount(); i++ )
    {
        if( !poFeature->IsFieldSet( i ) )
            continue;

        if( !bNeedComma )
            bNeedComma = TRUE;
        else
            osCommand += ", ";

        osCommand = osCommand 
             + poFeatureDefn->GetFieldDefn(i)->GetNameRef();
    }

    osCommand += ") VALUES (";

    // Set the geometry 
    bNeedComma = poFeature->GetGeometryRef() != NULL;
    if( poFeature->GetGeometryRef() != NULL)
    {
        char    *pszWKT = NULL;

        if( poFeature->GetGeometryRef() != NULL )
        {
            OGRGeometry *poGeom = (OGRGeometry *) poFeature->GetGeometryRef();
            
            poGeom->closeRings();
            poGeom->exportToWkt( &pszWKT );
        }

        if( pszWKT != NULL )