Question

正如标题所说，我正试图让Shiny显示一个SelectBox，这样我就可以从SQL Server表中动态选择记录，并根据CATEGORY的选择，显示表中的所有内容。下面的脚本必须关闭。我正在使SelectBox工作，但是当我做出选择时，什么也没有显示。

library(shiny)
library(RODBCext)

shinyApp(
  ui = 
    shinyUI(
      fluidPage(
        uiOutput("select_category"),
        tableOutput("display_data")
      #  plotOutput("plot_data")
      )
    ),


  server = shinyServer(function(input, output, session){

    # A reactive object to get the query. This lets you use
    # the data in multiple locations (plots, tables, etc) without
    # having to perform the query in each output slot.
    QueriedData <- 
      reactive({
        req(input$showDrop)
        ch <- odbcDriverConnect('driver={SQL Server};server=MyServer;database=Northwind;trusted_connection=true')
        showList <- sqlExecute(ch, 
                               "SELECT * FROM [NORTHWND].[dbo].[Customers] WHERE [CUSTOMERID] = ?",
                               data = list(AnalyteId = input$showDrop),
                               fetch = TRUE,
                               stringsAsFactors = FALSE)
        odbcClose(ch)
        showList
      })

    # The select input control.  These can be managed dynamically 
    # from the server, and then the control send back to the UI
    # using `renderUI`
    output$select_category <- 
      renderUI({
        ch <- odbcDriverConnect('driver={SQL Server};server=MyServer;database=Northwind;trusted_connection=true')
        showList <- sqlExecute(ch, 
                               "SELECT DISTINCT AnalyteId From [NORTHWND].[dbo].[Customers] ORDER BY [CUSTOMERID]", 
                               fetch = TRUE,
                               stringsAsFactors = FALSE)
        odbcClose(ch)
        selectInput(inputId = "showDrop",
                    label = "Select Asset",
                    showList$AnalyteId)
      })

    # Display the data in a table
    output$display_data <- 
      renderTable({
        QueriedData()
      })

    # Display a plot
    # output$plot_data <- 
    #   renderPlot({
    #     plot(QueriedData()) # fill in the plot code you want to use.
    #   })

  })
)

有人能帮我搞定吗？此外，您可以使表格动态选择，还是不是一个选项？

谢谢！

Answer 1

您似乎错过了一些组件。一些说明：

您的UI定义无效。 UI的每个参数都应该产生某种UI元素。您定义连接并从SQL Server导出数据的行将不会按照您期望的方式行事。您应该在服务器上执行这些操作，或者应该全局定义它们。

您正在检索output$cumReturn广告位中的数据，但您正在使用renderPlot来执行此操作。这有点不相干。如果要渲染绘图，则应生成绘图。如果您希望显示数据，则应使用renderTable（或类似内容）。

您还没有在UI中的任何位置显示cumReturn输出槽，因此实际上从未调用过查询。

最后，output$cumReturn中的查询在进入服务器时会失败。我猜你的意思是在input$showDrop语句中使用WHERE，但你的查询没有这样的陈述。这不会在上面的代码中输出错误，因为您从不尝试呈现cumReturn输出，因此永远不会调用查询。

以下是您的代码的变体，应该会生成属于该类别的数据表。

library(shiny)
library(RODBCext)

shinyApp(
  ui = 
    shinyUI(
      fluidPage(
        uiOutput("select_category"),
        tableOutput("display_data"),
        plotOutput("plot_data")
      )
    ),


  server = shinyServer(function(input, output, session){

    # A reactive object to get the query. This lets you use
    # the data in multiple locations (plots, tables, etc) without
    # having to perform the query in each output slot.
    QueriedData <- 
      reactive({
        req(input$showDrop)
        ch <- odbcDriverConnect('...')
        showList <- sqlExecute(ch, 
                               "SELECT * FROM dbo.Analyte WHERE AnalyteId = ?",
                               data = list(AnalyteId = input$showDrop),
                               fetch = TRUE,
                               stringsAsFactors = FALSE)
        odbcClose(ch)
        showList
      })

    # The select input control.  These can be managed dynamically 
    # from the server, and then the control send back to the UI
    # using `renderUI`
    output$select_category <- 
      renderUI({
        ch <- odbcDriverConnect('...')
        showList <- sqlExecute(ch, 
                               "SELECT DISTINCT AnalyteId FROM dbo.Analyte ORDER BY AnalyteId", 
                               fetch = TRUE,
                               stringsAsFactors = FALSE)
        odbcClose(ch)
        selectInput(inputId = "showDrop",
                    label = "Select Asset",
                    showList$AnalyteId)
      })

    # Display the data in a table
    output$display_data <- 
      renderTable({
        QueriedData()
      })

    # Display a plot
    output$plot_data <- 
      renderPlot({
        plot(QueriedData()) # fill in the plot code you want to use.
      })

  })
)

Answer 2

library(shiny)
library(RODBCext)

shinyApp(
  ui = 
    shinyUI(
      fluidPage(
        uiOutput("select_category"),
        tableOutput("display_data")
      #   plotOutput("plot_data")
      )
    ),

  # server needs the function; looks ok
  server = shinyServer(function(input, output, session)
    {
    # A reactive object to get the query. This lets you use
    # the data in multiple locations (plots, tables, etc) without
    # having to perform the query in each output slot.
    QueriedData <- reactive({
        req(input$showDrop)
        ch <- odbcDriverConnect("driver={SQL Server};server=SERVER;database=DB;trusted_connection=true")
        showList <- sqlExecute(ch, "SELECT * FROM [DB].[dbo].[TABLE] WHERE Category = ?",
                               data = list(Category = input$showDrop),
                               fetch = TRUE,
                               stringsAsFactors = FALSE)
        odbcClose(ch)
        showList
      })

    # The select input control.  These can be managed dynamically 
    # from the server, and then the control send back to the UI
    # using `renderUI`
     output$select_category <- renderUI({
         ch <- odbcDriverConnect("driver={SQL Server};server=SERVER;database=DB;trusted_connection=true")
         showList <- sqlExecute(ch, "Select Distinct Category From [DB].[dbo].[TABLE] Order by Category", 
                                fetch = TRUE,
                                stringsAsFactors = FALSE)
         odbcClose(ch)
         selectInput(inputId = "showDrop",
                     label = "Select Asset",
                     showList$Category)
       })

    # Display the data in a table
    output$display_data <- renderTable({
        QueriedData()
      })

    # Display a plot
    # output$plot_data <- 
    #  renderPlot({
    #    plot(QueriedData()) # fill in the plot code you want to use.
    #  })

  })
)

尝试使用Shiny SelectBox从SQL Server表中获取数据

2 个答案: