VFP 愛用者社區

Ruey · 註冊時間: 2003-03-12 文章: 1698 來自: tunglo 第 1 樓

來源:程式設計師俱樂部
http://programmer.eforum2000.net/pc2020v5/forum/ShowSameTitle.asp?URL=N&board_pc2020=foxpro&index=135&id=887&mode=&type_pc2020=sametitleLevel-2

作者 : Dani3911 [ 貼文 109 | 人氣 1.33 | 評價 0 ] 回應本文發表新文給予評價 4/25/03 5:41:44 PM
在 textbox 的 Valid Event 試試加上
LOCAL c,n
c=THIS.VALUE
SELECT * FROM table2 WHERE fieldn=c INTO CURSOR tempA
n=_TALLY
USE IN tempA
IF n>0
MESSAGEBOX('資料重複...!')
RETURN(0) && 限制回到該欄位, 不得離開(lost)
ENDIF
DODEFAULT()

作者 : JC [ 貼文 1 | 人氣 0.03 | 評價 0 ] 回應本文發表新文給予評價 5/16/03 1:13:55 AM
以下的方式也是可行!!
local _ve
_ve=this.value
if indexseek(_ve,.F.,"資料表格","索引")
=messagebox("輸入值已重覆!!")
retu 0
endif

jakan9 · 註冊時間: 2003-10-22 文章: 130 第 2 樓

如果欄位值𤰉有修改,還是會select 的到本筆資料,說資料重覆,其實𤰉有重覆,該如何做,請指導,thinks!

RORI · 發表於: 星期日二月 22, 2004 11:33 pm 文章主題:

PUT A FLAG THISFORM.OPMODE
THISFORM.OPMODE 1.ADD 2.MODIFY 3 DEFAULT 4 DELETE ......
OPMODE=1 ----> CHECK

catjoke · 發表於: 星期一二月 23, 2004 2:29 pm 文章主題:

第一個方法不是不用, 如果同時間有5-10個用家新增資料...

不幸最後的一個存檔時, 才順著跳出流水號, 足足檢查了10次才可以存檔...
你想想這個 SELECT-SQL 閃動了10次才告訴你成功存檔,
你有甚麼感受!? 很慢, 很花畫面似的! -_-"

方法2中 indexseek() 是新功能嗎!? 我用的VFP 版本太舊了.. (5.0)
只是另開一次 table, 並 search 它出來...

syntech · 發表於: 星期一二月 23, 2004 5:10 pm 文章主題:

INDEXSEEK() VFP6.0以上有.
以下為HELP 內容

Without moving the record pointer, searches an indexed table for the first occurrence of a record whose index key matches a specified expression.

Syntax

INDEXSEEK(eExpression [, lMovePointer [, nWorkArea | cTableAlias
[, nIndexNumber | cIDXIndexFileName | cTagName]]])

Returns

Logical

Arguments

eExpression

Specifies the index key expression for which you want INDEXSEEK( ) to search.

lMovePointer

Specifies if the record pointer is moved to the matching record. If lMovePointer is true (.T.) and a matching record exists, the record pointer is moved to the matching record. If lMovePointer is true (.T.) and a matching record doesn't exist, the record pointer isn’t moved. If lMovePointer is false (.F.) or is omitted, the record pointer isn't moved even if a matching record exists.

nWorkArea

Specifies the work area number of the table that is searched for the index key.

cTableAlias

Specifies the alias of the table that is searched. If you omit nWorkArea and cTableAlias, the table in the currently selected work area is searched.

nIndexNumber

Specifies the number of the index file or tag that is used to search for the index key. nIndexNumber refers to the index files as they are listed in USE or SET INDEX. Open .IDX files are numbered first in the order in which they appear in USE or SET INDEX. Tags in the structural .cdx file (if one exists) are then numbered in the order in which they were created. Finally, tags in any open independent .cdx files are numbered in the order in which they were created. For more information about index numbering, see SET ORDER.

cIDXIndexFileName

Specifies an .idx file that is used to search for the index key.

cTagName

Specifies a tag of a .cdx file that is used to search for the index key. The tag name can be from a structural .cdx file or any open independent .cdx file.

Note The .idx file takes precedence if duplicate .idx file and tag names exist.

Remarks

INDEXSEEK( ) returns true (.T.) if a match is found; otherwise false (.F.) is returned. You can use INDEXSEEK( ) only with a table with an index order set, and you can search only for an index key. The match must be exact unless SET EXACT is set to OFF.

INDEXSEEK( ) provides a fast way to search for records without moving the record pointer. Because the record pointer isn't moved, rules and triggers aren't executed. If INDEXSEEK( ) returns true (.T.) indicating that a matching record is found, you can execute INDEXSEEK( ) again with the second parameter lMovePointer set to true (.T.) to move to the matching record.

catjoke · 發表於: 星期一二月 23, 2004 5:46 pm 文章主題:

謝謝!

越來越覺得現今的程式員幸福!
e.g. 以前用寫 FCREATE(), FWRITE(), FPUTS(), FFLUSH(), FCLOSE() 等等..
才可以把資料寫到檔案去... 現在郤一行: STRTOFILE()

INDEXSEEK() 無須多開一次table 已能找到有否重覆, 出蟲的機會大大減少了..

an1060 · 發表於: 星期二三月 02, 2004 9:02 am 文章主題:

用INDEXSEEK()只能套用在新增一筆資料,如果是修改資料,那可就無法判別了.

最佳方式是同一個檔案,用不同的ALIAS開第二次
以目前值(This.Value),用SEEK()在第二個ALIAS上找尋,找到了,只要是兩個ALIAS之RECNO()不相等,那鐵定是資料重覆.