Merge pull request #422 from r-dbi/unquote

R/dbUnquoteIdentifier.R

@@ -26,21 +26,17 @@
 #'
 #' # The returned object is always a list,
 #' # also for Id objects
-#' dbUnquoteIdentifier(
-#'   ANSI(),
-#'   Id(catalog = "Catalog", schema = "Schema", table = "Table")
-#' )
+#' dbUnquoteIdentifier(ANSI(), Id("Catalog", "Schema", "Table"))
 #'
-#' # Quoting is the inverse operation to unquoting the elements
-#' # of the returned list
+#' # Quoting and unquoting are inverses
 #' dbQuoteIdentifier(
 #'   ANSI(),
 #'   dbUnquoteIdentifier(ANSI(), SQL("UnqualifiedTable"))[[1]]
 #' )
 #'
 #' dbQuoteIdentifier(
 #'   ANSI(),
-#'   dbUnquoteIdentifier(ANSI(), Id(schema = "Schema", table = "Table"))[[1]]
+#'   dbUnquoteIdentifier(ANSI(), Id("Schema", "Table"))[[1]]
 #' )
 setGeneric("dbUnquoteIdentifier",
   def = function(conn, x, ...) standardGeneric("dbUnquoteIdentifier")

R/dbUnquoteIdentifier_DBIConnection.R

@@ -1,45 +1,37 @@
 #' @rdname hidden_aliases
 #' @usage NULL
 dbUnquoteIdentifier_DBIConnection <- function(conn, x, ...) {
-  if (is(x, "SQL")) {
-    id_rx <- '(?:"((?:[^"]|"")+)"|([^". ]+))'
+  # Determine quoting character
+  quote_char <- substr(dbQuoteIdentifier(conn, ""), 1, 1)
 
-    rx <- paste0(
-      "^",
-      "(?:|(?:|", id_rx, "[.])",
-      id_rx, "[.])",
-      "(?:|", id_rx, ")",
-      "$"
-    )
+  if (is(x, "SQL") || is.character(x)) {
+    x <- lapply(x, unquote, quote_char = quote_char)
+    lapply(x, Id)
+  } else if (is(x, "Id")) {
+    list(x)
+  } else {
+    stop("x must be SQL, Id, or character", call. = FALSE)
+  }
+}
 
-    bad <- grep(rx, x, invert = TRUE)
-    if (length(bad) > 0) {
-      stop("Can't unquote ", x[bad[[1]]], call. = FALSE)
-    }
-    catalog <- gsub(rx, "\\1\\2", x)
-    catalog <- gsub('""', '"', catalog)
-    schema <- gsub(rx, "\\3\\4", x)
-    schema <- gsub('""', '"', schema)
-    table <- gsub(rx, "\\5\\6", x)
-    table <- gsub('""', '"', table)
+unquote <- function(x, quote_char) {
+  # replace doubled quotes with escaped quote
+  gsub <- gsub(
+    pattern = paste0(quote_char, quote_char),
+    replacement = paste0("\\", quote_char),
+    x
+  )
 
-    ret <- Map(catalog, schema, table, f = as_table)
-    names(ret) <- names(x)
-    return(ret)
-  }
-  if (is(x, "Id")) {
-    return(list(x))
-  }
-  stop("x must be SQL or Id", call. = FALSE)
+  scan(
+    text = x,
+    what = character(),
+    quote = quote_char,
+    quiet = TRUE,
+    na.strings = character(),
+    sep = "."
+  )
 }
 
 #' @rdname hidden_aliases
 #' @export
 setMethod("dbUnquoteIdentifier", signature("DBIConnection"), dbUnquoteIdentifier_DBIConnection)
-
-as_table <- function(catalog, schema, table) {
-  args <- c(catalog = catalog, schema = schema, table = table)
-  # Also omits NA args
-  args <- args[!is.na(args) & args != ""]
-  do.call(Id, as.list(args))
-}

tests/testthat/test-dbUnquoteIdentifier_DBIConnection.R

@@ -0,0 +1,20 @@
+test_that("can unquote any number of components", {
+  expect_equal(dbUnquoteIdentifier(ANSI(), "a"), list(Id("a")))
+  expect_equal(dbUnquoteIdentifier(ANSI(), "a.b"), list(Id("a", "b")))
+  expect_equal(dbUnquoteIdentifier(ANSI(), "a.b.c"), list(Id("a", "b", "c")))
+  expect_equal(dbUnquoteIdentifier(ANSI(), "a.b.c.d"), list(Id("a", "b", "c", "d")))
+})
+
+test_that("can unquote any quoted components", {
+  expect_equal(dbUnquoteIdentifier(ANSI(), '"a.b"'), list(Id("a.b")))
+
+  expect_equal(dbUnquoteIdentifier(ANSI(), 'a."b"'), list(Id("a", "b")))
+  expect_equal(dbUnquoteIdentifier(ANSI(), '"a".b'), list(Id("a", "b")))
+  expect_equal(dbUnquoteIdentifier(ANSI(), '"a"."b"'), list(Id("a", "b")))
+
+  expect_equal(dbUnquoteIdentifier(ANSI(), '"a"""."b"""'), list(Id('a"', 'b"')))
+})
+
+test_that("Id is unchanged and wrapped in list", {
+  expect_equal(dbUnquoteIdentifier(ANSI(), Id("foo")), list(Id("foo")))
+})

tests/testthat/test-quote.R

@@ -28,23 +28,3 @@ test_that("unquote Id", {
   expect_equal(dbUnquoteIdentifier(ANSI(), Id(table = "a", schema = "b", catalog = "c")),
     list(Id(table = "a", schema = "b", catalog = "c")))
 })
-
-test_that("unquote SQL", {
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL('"a"')), list(Id(table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL("a")), list(Id(table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL('"b"."a"')), list(Id(schema = "b", table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL("b.a")), list(Id(schema = "b", table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL('"c"."b"."a"')),
-    list(Id(catalog = "c", schema = "b", table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL('"c"."b"."a"')),
-    list(Id(catalog = "c", schema = "b", table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL("c.b.a")),
-    list(Id(catalog = "c", schema = "b", table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL('"c"."b.d"."a"')),
-    list(Id(catalog = "c", schema = "b.d", table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL('c."b""d".a')),
-    list(Id(catalog = "c", schema = 'b"d', table = "a")))
-  expect_equal(dbUnquoteIdentifier(ANSI(), SQL(c('"Catalog"."Schema"."Table"', '"UnqualifiedTable"'))),
-    list(Id(catalog = "Catalog", schema = "Schema", table = "Table"),
-      Id(table = "UnqualifiedTable")))
-})