数据库访问控件：递归 逻辑优化 望指教解决办法

数据库访问控件：递归 逻辑优化 望指教
实现思路：每调用一次递归函数，就查询一条记录并添加到treeview中（之前是把数据全查出来然后再递归）
相关数据仍是之前用到的数据结构

C/C++ code

void __fastcall TForm1::AddTree(AnsiString parentID,TTreeNode *Node){    SQLQuery1->SQL->Text=        "select a.PDMObject_ID as Id,  \        ISNULL(b.PDMObject_ID_Parent,0) as pId, a.User_ID, a.User_Name  \        from PDM_Users_Roles_ORG a left join  \        Pdm_Organization_tree b on a.PDMObject_ID=b.PDMObject_ID_Son  \        where a.PDMObject_ID in  \        (select distinct PDMObject_ID_Son as id from PDM_Organization_Tree \         union \        select distinct PDMObject_ID_Parent as id from PDM_Organization_Tree) \        and a.PDMObject_ID="+parentID;    SQLQuery1->Open();    for(SQLQuery1->First();!SQLQuery1->Eof;SQLQuery1->Next())    {        int Id,pId;        Id = SQLQuery1->FieldByName("Id")->AsInteger;        AnsiString text;        text.sprintf("%d(%s %s)",Id,                    SQLQuery1->FieldByName("User_ID")->AsString,                    SQLQuery1->FieldByName("User_Name")->AsString                    );        TTreeNode *temp_Node; //临时节点        if((int)Node->Data == parentID)   //若 == 则为父节点        {            for(int i = 0;i<TreeView1->Items->Count;i++ )       //遍历树            {                if( (int)TreeView1->Items->Item[i]->Data == parentID)                    temp_Node = TreeView1->Items->Item[i];        //指向父节点            }            Node = temp_Node;        }        temp_Node = TreeView1->Items->AddChild(Node,text);        temp_Node->Data = (void*)Id;        AddTree(SQLQuery1->FieldByName("pId")->AsString,Node);    }}

疑问：
1.对于表中的根节点（这里是3）由于根节点没有父亲（parentID）(处理后置0)该如何调用？
如：开始时调用AddTree（0,0）;不会读取根节点的相关数据
2.进行断点调试时，到if((int)Node->Data == parentID) 这句没有报错，进行下一步时报错：
Exception class EAccessViolation with message 'Access violation at address 00401F5F in module 'recursion.exe'. Read of address 0000000C'. Process recursion.exe (3864)
请指点 谢谢！

[解决办法]
试试

C/C++ code

void __fastcall TForm1::AddTree(AnsiString parentID,TTreeNode *Node){    SQLQuery1->SQL->Text=        "select a.PDMObject_ID as Id,  \        ISNULL(b.PDMObject_ID_Parent,0) as pId, a.User_ID, a.User_Name  \        from PDM_Users_Roles_ORG a left join  \        Pdm_Organization_tree b on a.PDMObject_ID=b.PDMObject_ID_Son  \        where a.PDMObject_ID in  \        (select distinct PDMObject_ID_Son as id from PDM_Organization_Tree \         union \        select distinct PDMObject_ID_Parent as id from PDM_Organization_Tree) \        and pId ="+parentID;    SQLQuery1->Open();    for(SQLQuery1->First();!SQLQuery1->Eof;SQLQuery1->Next())    {        int Id,pId;        Id = SQLQuery1->FieldByName("Id")->AsInteger;        AnsiString text;        text.sprintf("%d(%s %s)",Id,                    SQLQuery1->FieldByName("User_ID")->AsString,                    SQLQuery1->FieldByName("User_Name")->AsString                    );        TTreeNode *temp_Node; //临时节点        if(Node && (int)Node->Data == parentID)   //若 == 则为父节点        {            for(int i = 0;i<TreeView1->Items->Count;i++ )       //遍历树            {                if( (int)TreeView1->Items->Item[i]->Data == parentID)                    temp_Node = TreeView1->Items->Item[i];        //指向父节点            }            Node = temp_Node;        }        temp_Node = TreeView1->Items->AddChild(Node,text);        temp_Node->Data = (void*)Id;        AddTree(SQLQuery1->FieldByName("pId")->AsString,Node);    }}
------解决方案-------------------- 
 
SQLQuery1->SQL->Text = .... ;  
SQLQuery1->Open();
for(SQLQuery1->First();!SQLQuery1->Eof;SQLQuery1->Next())
{
 .....\\Find ParentNode
 temp_Node = TreeView1->Items->AddChild(Node,text);
 ...
 AddTree(SQLQuery1->FieldByName("pId")->AsString,Node);//这里递归?
}
//这样是不行的吧。。。SQLQuery1作为全局数据，如何遍历记录集？

"每调用一次递归函数，就查询一条记录"，如果是确认只查询回一条记录，又何必 for ...



 

 

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