問題描述
我嘗試使用 XQuery .nodes 將 XML 分解到一個臨時表中，如下所示.但是，我遇到了性能問題.粉碎需要很多時間.請給我一個關于此替代方案的想法.
I tried to shred XML into a temporary table by using XQuery .nodes as follows. But, I got performance problem. It is taking much time to shred. Please give me an idea on alternatives for this.
我的要求是將批量記錄傳遞給存儲過程并解析這些記錄并根據記錄值執行一些操作.
My requirement is to pass bulk records to a stored procedure and parse those records and do some operation based on record values.
CREATE TABLE #DW_TEMP_TABLE_SAVE(
[USER_ID] [NVARCHAR](30),
[USER_NAME] [NVARCHAR](255)
)
insert into #DW_TEMP_TABLE_SAVE
select
A.B.value('(USER_ID)[1]', 'nvarchar(30)' ) [USER_ID],
A.B.value('(USER_NAME)[1]', 'nvarchar(30)' ) [USER_NAME]
from
@l_n_XMLDoc.nodes('//ROW') as A(B)
推薦答案
在 values 子句中指定 text() 節點.
Specify the text() node in your values clause.
insert into #DW_TEMP_TABLE_SAVE
select A.B.value('(USER_ID/text())[1]', 'nvarchar(30)' ) [USER_ID],
A.B.value('(USER_NAME/text())[1]', 'nvarchar(30)' ) [USER_NAME]
from @l_n_XMLDoc.nodes('/USER_DETAILS/RECORDSET/ROW') as A(B)
不使用 text() 將創建一個查詢計劃，該計劃嘗試將來自指定節點的值與其所有子節點連接起來，我想在這種情況下您不希望這樣.如果您不使用 text()，則查詢的連接部分由 UDX 運算符完成，最好不要在您的計劃中使用它.
Not using text() will create a query plan that tries concatenate the values from the specified node with all its child nodes and I guess you don't want that in this scenario. The concatenation part of the query if you don't use text() is done by the UDX operator and it is a good thing not to have it in your plan.
另一件要嘗試的事情是 OPENXML.在某些情況下(大型 xml 文檔)，我發現 OPENXML 執行速度更快.
Another thing to try is OPENXML. In some scenarios (large xml documents) I have found that OPENXML performs faster.
declare @idoc int
exec sp_xml_preparedocument @idoc out, @l_n_XMLDoc
insert into #DW_TEMP_TABLE_SAVE
select USER_ID, USER_NAME
from openxml(@idoc, '/USER_DETAILS/RECORDSET/ROW', 2)
with (USER_ID nvarchar(30), USER_NAME nvarchar(30))
exec sp_xml_removedocument @idoc
這篇關于SQL 中 XML 粉碎的替代方案的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！