delphi 编程技巧

				在delphi4.0中如何真正删除dbf文件记录 (2000年11月20日) 
				
				本站更新  分类:   作者:dfw  推荐:   阅读次数:527  
				(http://www.codesky.net)  
				
				--------------------------------------------------------------------------------
				在delphi4.0中如何真正删除dbf文件记录，DBIPACKTABLE具体如何用(100分) 
				问题的分类是：数据库 - 文件型 , 分坛主: SeaSky, 分坛主: yifeng 
				
				来自：sxzww 时间：00-3-11 11:11:10 ID:197921 
				我的语句如下：
				sql.clear;
				SQL.ADD('delete from xz_jybj');
				q2.execsql;
				close;
				执行后，只在数据文件xz_jybj中做了删除标记，
				我查询过这个站点关于delete 记录的有关内容，似乎可以用DBIPACKTABLE
				函数,但我看不懂,谁能帮助我，谢谢 。
				
				
				
				
				
				--------------------------------------------------------------------------------
				来自：xWolf 时间：00-3-11 11:37:56 ID:197934 
				procedure PackTable(Table: TTable);
				var
				Props: CURProps;
				begin
				// 必须以独占方式打开
				if (not Table.Active) or (not Table.Exclusive) then Exit;
				Check(DBIGetCursorProps(Table.Handle, Props));
				// 必须是dBase或FoxPro
				if Props.szTableType  szDBASE then Exit;
				Check(DBIPackTable(Table.DBHandle, Table.Handle, nil, szDBASE, True));
				Table.Open;
				end;
				
				
				
				--------------------------------------------------------------------------------
				来自：xWolf 时间：00-3-11 11:47:51 ID:197941 
				function DbiPackTable (hDb: hDBIDb; hCursor: hDBICur; pszTableName: PChar; pszDriverType: PChar; bRegenIdxs: Bool): DBIResult stdcall;
				参数说明:
				hDB: 数据库句柄,可以由TTable.DBHandle得到
				hCursor: 数据表关联的游标,若为nil则数据表依赖于pszTableName和pszDriverType
				bRegenIdxs决定是否关联外接的索引文件尤其是MDX多索引文件
				
				
				以下摘自Delphi Help
				Example 1: Pack a Paradox or dBASE table.
				
				This example will pack a Paradox or dBASE table therfore removing already deleted rows 
				in a table. This function will also regenerate all out-of-date indexes (maintained 
				indexes). This example uses the following input:
				
				PackTable(Table1)
				
				The function is defined as follows: 
				
				// Pack a Paradox or dBASE table
				// The table must be opened execlusively before calling this function...
				procedure PackTable(Table: TTable);
				var
				Props: CURProps;
				hDb: hDBIDb;
				TableDesc: CRTblDesc;
				begin
				// Make sure the table is open exclusively so we can get the db handle...
				if not Table.Active then
				raise EDatabaseError.Create('Table must be opened to pack');
				if not Table.Exclusive then
				
				raise EDatabaseError.Create('Table must be opened exclusively to pack');
				
				// Get the table properties to determine table type...
				Check(DbiGetCursorProps(Table.Handle, Props));
				
				// If the table is a Paradox table, you must call DbiDoRestructure...
				if Props.szTableType = szPARADOX then begin
				// Blank out the structure...
				FillChar(TableDesc, sizeof(TableDesc), 0);
				// Get the database handle from the table's cursor handle...
				
				Check(DbiGetObjFromObj(hDBIObj(Table.Handle), objDATABASE, hDBIObj(hDb)));
				// Put the table name in the table descriptor...
				StrPCopy(TableDesc.szTblName, Table.TableName);
				// Put the table type in the table descriptor...
				StrPCopy(TableDesc.szTblType, Props.szTableType);
				// Set the Pack option in the table descriptor to TRUE...
				TableDesc.bPack := True;
				// Close the table so the restructure can complete...
				Table.Close;
				// Call DbiDoRestructure...
				
				Check(DbiDoRestructure(hDb, 1, @TableDesc, nil, nil, nil, False));
				end
				else
				// If the table is a dBASE table, simply call DbiPackTable...
				if (Props.szTableType = szDBASE) then
				Check(DbiPackTable(Table.DBHandle, Table.Handle, nil, szDBASE, True))
				else
				// Pack only works on PAradox or dBASE; nothing else...
				raise EDatabaseError.Create('Table must be either of Paradox or dBASE ' +
				
				'type to pack');
				
				Table.Open;
				
				end;
				
				
				
				--------------------------------------------------------------------------------
				来自：sxzww 时间：00-3-11 15:36:04 ID:198012 
				接受答案了.
				 
				 
				
				
				--------------------------------------------------------------------------------