vb.net 检查sql server数据库中是否存在一行，然后使用vb.net删除
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Check if a row exists in sql server database then delete using vb.net
提问by user3284316
Problem:I am currently using a vb application(Visual Studio 2012) to query my database (SQL Server 2012) to check if the row exists in a table if the row does exist then delete it. However if it does not exist then add the row to the database.
问题：我目前正在使用 vb 应用程序 (Visual Studio 2012) 查询我的数据库 (SQL Server 2012) 以检查该行是否存在于表中，如果该行确实存在，则将其删除。但是，如果它不存在，则将该行添加到数据库中。
Additional information:I have text boxes on my vb application with the data. This data is saved to the database.
附加信息：我的 vb 应用程序中有包含数据的文本框。该数据被保存到数据库中。
I have complied the code and cannot seem to find the error in the line of code. Please find the code below!
我已经编译了代码，但似乎无法在代码行中找到错误。请找到下面的代码！
Code:
代码：
cmd2.CommandText =
"IF EXISTS(SELECT * FROM(tblLocation) WHERE Tag_ID = '"
& txttags.Text
& "') THEN (DELETE FROM tblLocation WHERE Tag_ID = '"
& txttags.Text
& ")' ELSE INSERT INTO tblLocation([Area], [Area_Time], [TagID]) VALUES('"
& txtLocation.Text & "' , '"
& txtdate.Text & "','" & txttags.Text & "')"
Any help or suggestions would be greatly appreciated!
任何帮助或建议将不胜感激！
采纳答案by wdosanjos
Remove the parenthesis before/after the DELETE statement as follows:
删除 DELETE 语句之前/之后的括号，如下所示：
cmd2.CommandText =
"IF EXISTS(SELECT * FROM tblLocation WHERE Tag_ID = '"
& txttags.Text
& "') DELETE FROM tblLocation WHERE Tag_ID = '"
& txttags.Text
& "' ELSE INSERT INTO tblLocation([Area], [Area_Time], [TagID]) VALUES('"
& txtLocation.Text & "' , '"
& txtdate.Text & "','" & txttags.Text & "')"
