rhandsontable on multiple tables from SQlite database - r

Question

Assistance will be greatly appreciated.
I am working on a shiny app which involves the use of both multiple SQlite databases and rhandsontable package. I found alot of helpful material online with respect to using this package but I am at a level of frustration as I spend 2 days stuck on one problem which I think its worth asking.
So the script below depicts the server and the UI of the rhandsontable. I wanted to be able to enable the user edit, and safe their modified table (which is covered alot online) but across multiple tables (something I am struggling with)
What my code does is that it opens the 1st table, and yes If i make a modification it does safe. But when I attempt to go to another table through the select input, the other table content immediately gets REPLACED by the initial modified one.
I really would like the modifications to be independent without affecting other tables.
Again, assistance will be greatly appreciated.
downloadTableUI <- function(id) {
ns <- NS(id)
tagList(
sidebarLayout(
sidebarPanel(
selectInput(ns("dataset"), "Choose a dataset:",
choices = dput(as.character(alltables[1: NROW(alltables)]))),
radioButtons(ns("filetype"), "File type:",
choices = c("csv", "tsv")),
dateRangeInput(ns("daterange2"), "Date Filtration",
start = "2017-02-17",
end = "2017-03-07"),
actionButton(ns("saveBtn"), "Save"),
br(),
downloadButton(ns('downloadData'), 'Download File', class = "btn-info")
),
mainPanel(
rHandsontableOutput(ns('tabletest'), width = 730, height = 600)
),
position = c("left")
)
)
}
DownloadTable <- function(input, output, session, pool) {
#select databases
tableChoozer <- reactive({input$dataset})
# dateSelector <- reactive({input$daterange2})
# Initiate the reactive table
p1 <- reactive({
results <- dbGetQuery(pool, paste('select * from ', tableChoozer()))
return (results)
})
Mychanges <- reactive({
observe({
input$saveBtn# update database file each time the button is pressed
if (!is.null(input$tabletest)) {#if there 's a table input
dbWriteTable(pool, tableChoozer(),hot_to_r(input$tabletest), overwrite = TRUE, row.names = FALSE)# overwrite the database
}
})
#THIS IS WHERE I THINK THE PROBLEM IS
if (is.null(input$tabletest)) {
return (p1())
} else if (!identical(p1(), input$tabletest)) {
mytable <- as.data.frame(hot_to_r(input$tabletest))
return (mytable)
}
})
output$tabletest <- renderRHandsontable({
rhandsontable(Mychanges()) %>%
hot_cols(columnSorting = TRUE, highlightCol = TRUE, highlightRow = TRUE,allowRowEdit = FALSE, allowColEdit = FALSE, exportToCsv = TRUE)
})
output$downloadData <- downloadHandler(
filename = function() {
paste("table.csv")
},
content = function(file) {
sep <- switch (input$filetype, "csv" = ",", "tsv" = "\t")
write.table(p1(), file, sep = sep, row.names = FALSE)
}
)
}

Answer 1

This code is untested, but hopefully it will work. Put the following at the top level of your server.R file
observeEvent( input$saveBtn,
{
# update database file each time the button is pressed
if (!is.null(input$tabletest)) {
#if there 's a table input
dbWriteTable(pool, tableChoozer(),
hot_to_r(input$tabletest), overwrite = TRUE, row.names = FALSE)
# overwrite the database
},
ignoreInit = TRUE
)
Using observeEvent rather than observe prevents a reactive dependency on tableChoozer and input$tabletest which seems to be your problem. ignoreInit makes it so the save event is not triggered at the initialization of the savebutton.