R shiny crashed even after trycatch()

Question

Below is the part of my server code. Actually there is an error in SQL for some conditions. So when I execute in R calling SQL, the R shiny crashes. So i tried putting trycatch(). Even then the app crashes but I can see notifications when app crashes. Please anyone help

if(input$ID != "" && !is.null(input$Date)){

      # to get data from SQL
      tryCatch({
      # to get data from SQL
      sql <- paste0("SELECT * FROM [SSS].[AAA].[CCC]")
      df1 <- sqlQuery(db, sql)   # db is already declared
        },

      error = function(err){
        showNotification(paste0(err), type = 'err')
      })

user12728748 · Accepted Answer · 2020-02-12T15:01:05.320

0

You could try to do df1 <- sqlQuery(db, sql, errors=FALSE), which should return -1; you could then check df1 != -1 before continuing in your code.

edit: You could do something like:

myReactiveFun <- reactive({
  shiny::req(input$Date)
  sql <- paste0("SELECT * FROM [SSS].[AAA].[CCC]")
  df1 <- sqlQuery(db, sql, errors=FALSE) 
  shiny::validate(shiny::need( df1 != -1, "need valid SQL query result...")

})

edited Feb 12 '20 at 15:01

answered Feb 12 '20 at 14:25

user12728748

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yes i got. but I get notification now. But it the original message and not what is there in "Show notification". May I know why? – imran p Feb 12 '20 at 14:30
Also can we copy sql error messages to ````show notification```` – imran p Feb 12 '20 at 15:32
see https://stackoverflow.com/questions/3501528/rodbc-functions-and-errors-warnings for a way to do that – user12728748 Feb 13 '20 at 16:20
Feel free to mark the question as answered if this answered it. – user12728748 Feb 13 '20 at 17:19

R shiny crashed even after trycatch()

1 Answers1