Fix error in qc.df() when no query is active

Previously, the examples/app-database.R would shown an error on
startup because the initial query was "", which was then sent
as a SQL query to RSQLite. The get_lazy_data code path accounted
for the "" query, so we decided to make the eager code path just
call the lazy code path, then collect().

Also fixed a formatting issue with the table.

Author: jcheng5

pkg-r/R/data_source.R

@@ -97,7 +97,7 @@ execute_query <- function(source, query, ...) {
 
 #' @export
 execute_query.dbi_source <- function(source, query, ...) {
-  DBI::dbGetQuery(source$conn, query)
+  dplyr::collect(get_lazy_data(source, query))
 }
 
 #' Test a SQL query on a data source.

pkg-r/examples/app-database.R

@@ -53,7 +53,7 @@ ui <- page_sidebar(
   p(
     "The table below shows the current filtered data based on your chat queries:"
   ),
-  DT::DTOutput("data_table"),
+  DT::DTOutput("data_table", fill = FALSE),
   br(),
   h3("Current SQL Query"),
   verbatimTextOutput("sql_query"),