更正此 SQL 查询：错误“Microsoft Jet 数据库引擎找不到输入表或查询 'IF'”

Question

我应该说嗨专家：D。帮我写这段漂亮的代码:)

数据库：

"ID（主键）" | “标题”
0 | “标题1”
1 | “标题2”
2 | “标题3”
3 | “标题4”

---

Sub AddRecord(ByVal Table As String, ByVal Columns As String, ByVal Record() As String)
    Dim SubDir As String = ""

    Dim Adapter As OleDbDataAdapter = New OleDbDataAdapter("SELECT * FROM " & Table, connectionString)
    Dim command As OleDbCommand
    Dim tbCorrectSyntax = ""

    Using connection As New OleDbConnection(connectionString)
        Try
            connection.Open()
            Dim Commandtxt As String = ""
            For i = 0 To Record.GetUpperBound(0)
                If Record(i).IndexOf(",") > 0 Then
                    Dim tmpRec() As String = Nothing
                    Dim cols() As String = Nothing

                    tmpRec = Record(i).Split(",")
                    cols = Columns.Split(",")

                    For j = 0 To tmpRec.GetUpperBound(0)
                        tbCorrectSyntax &= cols(j) & " = '" & tmpRec(j) & "' " & IIf(j = tmpRec.GetUpperBound(0), "", " , ")
                    Next
                End If


                Dim txtCorrect As String = IIf(tbCorrectSyntax = "", Columns & " = " & Record(i), tbCorrectSyntax)

                Commandtxt = "IF OBJECT_ID ( 'InsertOrUpdateItem', 'P' ) IS NOT NULL " & _
                                "DROP PROCEDURE InsertOrUpdateItem " & _
                             "GO " & _
                             "CREATE PROCEDURE InsertOrUpdateItem " & _
                                "AS " & _
                                "IF (EXISTS (SELECT * FROM " & Table & _
                                            " WHERE " & txtCorrect & "))" & _
                                            " begin " & _
                                                "UPDATE (" & Table & ") " & _
                                                txtCorrect & _
                                                " WHERE " & txtCorrect & " " & _
                                            " End " & _
                                            " else " & _
                                                " begin " & _
                                                " INSERT INTO " & Table & " (" & Columns & ") " & _
                                                " VALUES (" & Record(i) & ")" & _
                                            " End " & _
                                "End "

                'Commandtxt = "INSERT INTO " & Table & " (" & Columns & ") VALUES (" & Record(i) & ")"
                command = New OleDbCommand(Commandtxt, connection)
                command.CommandType = CommandType.StoredProcedure
                command.ExecuteNonQuery()

            Next


        Catch ex As Exception
            msgbox(ex.Message)
        Finally
            connection.Close()
        End Try
    End Using
End Sub

Function connectionString() As String
    Return "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & DBdir & ";User Id=admin;Password=;"
End Function

---

第一个过程是将数据添加到数据库字段的包装器（如果数据不存在） 但是用已经存在的新数据更新它。

输入：
表 = 表名
Columns = 将要更新的列的名称，以逗号分隔（Ex1：“ID”，Ex2：“ID,Title,...”）
Record() = 表示新值的字符串数组（多个值用逗号分隔）

好的，在向数据库添加值之前，我们应该检查是否存在具有该值的行:)
为此，创建存储过程是快速处理数据库的最佳方式。

所以...现在的问题是，在运行时，Miss OleDB 抛出了这个错误：
Microsoft Jet 数据库引擎找不到输入表或查询 'IF' ....

提前致谢：D

Answer 1

 command.CommandType = CommandType.StoredProcedure 

您声称您正在运行存储过程（CommandText 将是现有 SProc 的名称）。您实际上是在给它一个要直接执行的 SQL 命令。 CommandType 应该是 Text；

Answer 2

我找到了解决问题的方法（通过一些网络研究:)）哈哈哈我很高兴
无论如何，最初的问题是：“如何更新数据库中的记录（如果存在）” 所以我尝试在数据库中创建和存储一个存储过程......但是...... :)

然后我发现了一个有趣的方法：OleDBcommand 类的 ExecuteScalar

它只是根据 Sql 输入返回一个值：在我使用的以下示例中，如果记录存在，它返回索引（主键）。那么让我们开始吧：

Function GetRecordIndex(ByVal Table As String, ByVal Columns As String, ByVal Record As String) As String
    Dim Commandtxt As String = ""
    Dim Command As OleDbCommand
    Dim tbCorrectSyntax As String = ""
    Dim tbCorrectSyntaxAND As String = ""

    Using connection As New OleDbConnection(connectionString)

        Try
            connection.Open()
            If Record.IndexOf(",") > 0 Then
                Dim tmpRec() As String = Nothing
                Dim cols() As String = Nothing

                tmpRec = Record.Split(",")
                cols = Columns.Split(",")

                For j = 0 To tmpRec.GetUpperBound(0)
                    tbCorrectSyntax &= cols(j) & "='" & tmpRec(j) & "' " & IIf(j = tmpRec.GetUpperBound(0), "", " , ")
                    tbCorrectSyntaxAND &= cols(j) & "='" & tmpRec(j) & "' " & IIf(j = tmpRec.GetUpperBound(0), "", " AND ")
                Next
            End If
            Dim txtCorrect As String = IIf(tbCorrectSyntax = "", Columns & "=" & Record, tbCorrectSyntax)
            Dim txtCorrectAND As String = IIf(tbCorrectSyntaxAND = "", Columns & "=" & Record, tbCorrectSyntaxAND)

            Commandtxt = "SELECT * FROM " & Table & " WHERE " & txtCorrectAND
            Command = New OleDbCommand(Commandtxt, connection)
            Dim RecordIndex As String = Command.ExecuteScalar

            Return RecordIndex

        Catch ex As Exception
            Return Nothing
        Finally
            connection.Close()
        End Try
    End Using
End Function

和以前一样，Columns 参数可以是单个数据库列，也可以是用逗号分隔的多个列。与表示每列内数据的 Record 相同

感谢您的帮助
法德洛夫斯基