ADO資料集元件之CursorType和LockType屬性 |
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cashxin2002
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ADO資料集元件(如ADODataSet, ADOTable, ADOQuery等)﹐其皆具有CursorType和LockType屬性﹐其中各屬性值之解釋意義如下﹕ 摘自[Delphi6實務經典][林金霖]
---------------------------------------- CursorType屬性值﹕ ctUnspecified: 代表游標形態尚未指定; ctOpenForwardOnly: 代表開啟一個只能向前的游標﹐也就是不能使用Prior操作方法將游標向后移; ctKeyset: 代表開啟一個ctKey形態的游標﹐它表示其它使用者所做的修改并不會即時的更新客戶端的資料內容的游標形態; ctDynamic: 代表開啟一個ctDynamic形態的游標﹐它表示其它使用者所作的修改會即時更新﹐而且可以任意操作游標; ctStatic: 代表開啟一個STatic形態的游標﹐通常用于使用報表的制作﹐其它使用者的資料修改并不會做即時的更新﹒ LockType屬性值﹕ LtUnspecfified: 代表Lock形態尚未指定; LtReadOnly: 代表此物件將以唯讀的方式開啟﹐因此無法執行新增﹑修改﹑刪 除等編輯功能; LtPessimistic: 代表當資料來源的資料正在更新時﹐系統會暫時鎖住其它使用者的動作﹐以确保資料的一致性; LtOptimistic: 代表當資料來源的資料正在更新時﹐系統不會鎖住其它使用者的動作﹐因此其它使用者同樣可以對資料進行新增﹑修改﹑刪除等編輯動作; LtBatchOptimistic: 通常使用于批次更新作業中﹒ ---------------------------------------- 努力,相信會獲得美麗! 忻晟 發表人 - cashxin2002 於 2003/07/26 16:01:35 發表人 - cashxin2002 於 2003/07/27 03:13:20
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忻晟 編輯記錄
GrandRURU 重新編輯於 2016-06-16 16:26:52, 註解 無‧
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timhuang
尊榮會員 發表:78 回覆:1815 積分:1608 註冊:2002-07-15 發送簡訊給我 |
Hi, 關於 LockType 的屬性值, 應該是 lt 開頭, 不是 It 開頭哦. 就像 CursorType 是 ct 開頭是一樣的!! 順便貼上在 help 中的英文說明: CursorType :
ctUnspecified A specific cursor type has not yet been specified. ctOpenForwardOnly Forward-only cursor in which you can only scroll forward; better performance because only requires single through recordset. ctKeyset Keyset cursor; records added by other users are not visible; records deleted by other users are inaccessible. ctDynamic Dynamic cursor; data modifications, deletions, and insertions by other users are visible; scrolling forward and back allowed. ctStatic Static cursor; static copy of records; data changes by other users not visible; used mostly for reporting.LockType : ltUnspecified A specific lock type has not been specified or determined. ltReadOnly Read-only; the current execution cannot modify data. ltPessimistic Pessimistic locks; locks instantiated on a record-by-record basis when edit mode is applied to a record. ltOptimistic Optimistic locks; locked are initiated on a record-by-record basis, but only when updates are applied and a record is being updated. ltBatchOptimistic Optimistic batch updates; used for batch update mode rather than immediate update mode. |
cashxin2002
版主 發表:231 回覆:2555 積分:1937 註冊:2003-03-28 發送簡訊給我 |
引言: Hi, 關於 LockType 的屬性值, 應該是 lt 開頭, 不是 It 開頭哦. 就像 CursorType 是 ct 開頭是一樣的!! 順便貼上在 help 中的英文說明: CursorType :謝謝timhuang前輩的指正﹒ 小弟最近好像經常筆誤... 壓力太大了﹐請各位多多見諒﹗ 已修正以上之錯誤﹒謝謝﹗ 努力,相信會獲得美麗! 忻晟ctUnspecified A specific cursor type has not yet been specified. ctOpenForwardOnly Forward-only cursor in which you can only scroll forward; better performance because only requires single through recordset. ctKeyset Keyset cursor; records added by other users are not visible; records deleted by other users are inaccessible. ctDynamic Dynamic cursor; data modifications, deletions, and insertions by other users are visible; scrolling forward and back allowed. ctStatic Static cursor; static copy of records; data changes by other users not visible; used mostly for reporting.LockType :ltUnspecified A specific lock type has not been specified or determined. ltReadOnly Read-only; the current execution cannot modify data. ltPessimistic Pessimistic locks; locks instantiated on a record-by-record basis when edit mode is applied to a record. ltOptimistic Optimistic locks; locked are initiated on a record-by-record basis, but only when updates are applied and a record is being updated. ltBatchOptimistic Optimistic batch updates; used for batch update mode rather than immediate update mode.
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忻晟 |
領航天使
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