数据库操作示例

以下示例显示了 theroutine，它创建一个新数据库，获取模型空间块表记录，并创建两个添加到模型空间的圆。它使用函数来保存绘图。第二个例程在保存的图形中读取，打开模型空间块表记录，并循环访问它，打印它所包含的实体的类名。createDwg()AcDbDatabase::saveAs()readDwg()

void
createDwg()
{
    AcDbDatabase *pDb = new AcDbDatabase();
    AcDbBlockTable *pBtbl;
    pDb->getSymbolTable(pBtbl, AcDb::kForRead);
    AcDbBlockTableRecord *pBtblRcd;
    pBtbl->getAt(ACDB_MODEL_SPACE, pBtblRcd,
        AcDb::kForWrite);
    pBtbl->close();
    AcDbCircle *pCir1 = new AcDbCircle(AcGePoint3d(1,1,1),
                                       AcGeVector3d(0,0,1),
                                       1.0),
               *pCir2 = new AcDbCircle(AcGePoint3d(4,4,4),
                                       AcGeVector3d(0,0,1),
                                       2.0);
    pBtblRcd->appendAcDbEntity(pCir1);
    pCir1->close();
    pBtblRcd->appendAcDbEntity(pCir2);
    pCir2->close();
    pBtblRcd->close();
    // AcDbDatabase::saveAs() does 
not
 automatically
    // append a DWG file extension, so it
    // must be specified.
    //
    pDb->saveAs(_T("c:\\test1.dwg"));
    delete pDb;
}
void
readDwg()
{
    // Set constructor parameter to kFalse so that the
    // database will be constructed empty.  This way only
    // what is read in will be in the database.
    //
    AcDbDatabase *pDb = new AcDbDatabase(Adesk::kFalse);
    // The AcDbDatabase::readDwgFile() function
    // automatically appends a DWG extension if it is not
    // specified in the filename parameter.
    //
    if(Acad::eOk != pDb->readDwgFile(_T("c:\\test1.dwg")))
	return;
    // Open the model space block table record.
    //
    AcDbBlockTable *pBlkTbl;
    pDb->getSymbolTable(pBlkTbl, AcDb::kForRead);
    AcDbBlockTableRecord *pBlkTblRcd;
    pBlkTbl->getAt(ACDB_MODEL_SPACE, pBlkTblRcd,
        AcDb::kForRead);
    pBlkTbl->close();
    AcDbBlockTableRecordIterator *pBlkTblRcdItr;
    pBlkTblRcd->newIterator(pBlkTblRcdItr);
    AcDbEntity *pEnt;
    for (pBlkTblRcdItr->start(); !pBlkTblRcdItr->done();
        pBlkTblRcdItr->step())
    {
        pBlkTblRcdItr->getEntity(pEnt,
            AcDb::kForRead);
        acutPrintf("classname: %s\n",
            (pEnt->isA())->name());
        pEnt->close();
    }
    pBlkTblRcd->close();
    delete pBlkTblRcdItr;
    delete pDb;
}