Merge pull request #417 from r-dbi/unnamed-id

feat: `Id()` now accepts unnamed components

R/00-Id.R

@@ -6,10 +6,10 @@ setClass("Id", slots = list(name = "character"))
 #' Refer to a table nested in a hierarchy (e.g. within a schema)
 #'
 #' @description
-#' Objects of class `Id` have a single slot `name`, which is a named
-#' character vector.
+#' Objects of class `Id` have a single slot `name`, which is a character vector.
 #' The [dbQuoteIdentifier()] method converts `Id` objects to strings.
 #' Support for `Id` objects depends on the database backend.
+#'
 #' They can be used in the following methods as `name` or `table` argument:
 #'
 #' - [dbCreateTable()]
@@ -21,35 +21,38 @@ setClass("Id", slots = list(name = "character"))
 #'
 #' Objects of this class are also returned from [dbListObjects()].
 #'
-#' @param ... Components of the hierarchy, e.g. `schema`, `table`,
-#'   or `cluster`, `catalog`, `schema`, `table`,
-#'   depending on the database backend.
-#'   For more on these concepts, see
-#'   \url{https://stackoverflow.com/questions/7022755/}
+#' @param ... Components of the hierarchy, e.g. `schema`, `table`, or `cluster`,
+#'  `catalog`, `schema`, `table`, depending on the database backend. For more
+#'  on these concepts, see <https://stackoverflow.com/questions/7022755/>
 #' @export
 #' @examples
 #' # Identifies a table in a specific schema:
+#' Id("dbo", "Customer")
+#' # You can name the components if you want, but it's not needed
 #' Id(schema = "dbo", table = "Customer")
 #'
-#' # Identifies a table in a specific cluster, catalog, and schema:
-#' Id(cluster = "mycluster", catalog = "mycatalog", schema = "myschema", table = "mytable")
-#'
 #' # Create a SQL expression for an identifier:
-#' dbQuoteIdentifier(ANSI(), Id(schema = "nycflights13", table = "flights"))
+#' dbQuoteIdentifier(ANSI(), Id("nycflights13", "flights"))
 #'
 #' # Write a table in a specific schema:
 #' \dontrun{
-#' dbWriteTable(con, Id(schema = "myschema", table = "mytable"), data.frame(a = 1))
+#' dbWriteTable(con, Id("myschema", "mytable"), data.frame(a = 1))
 #' }
 Id <- function(...) {
   components <- c(...)
-  if (is.null(names(components)) || any(names(components) == "")) {
-    stop("All arguments to Id() must be named.", call. = FALSE)
+  if (!is.character(components)) {
+    stop("All elements of `...` must be strings.", call. = FALSE)
   }
-  new("Id", name = components)
+
+  new("Id", name = c(...))
 }
 
 #' @export
 toString.Id <- function(x, ...) {
-  paste0("<Id> ", paste0(names(x@name), " = ", x@name, collapse = ", "))
+  paste0("<Id> ", dbQuoteIdentifier(ANSI(), x))
+}
+
+
+dbQuoteIdentifier_DBIConnection_Id <- function(conn, x, ...) {
+  SQL(paste0(dbQuoteIdentifier(conn, x@name), collapse = "."))
 }

R/dbQuoteIdentifier_DBIConnection.R

@@ -3,9 +3,6 @@
 dbQuoteIdentifier_DBIConnection <- function(conn, x, ...) {
   # Don't support lists, auto-vectorization violates type stability
   if (is(x, "SQL")) return(x)
-  if (is(x, "Id")) {
-    return(SQL(paste0(dbQuoteIdentifier(conn, x@name), collapse = ".")))
-  }
   if (!is.character(x)) stop("x must be character or SQL", call. = FALSE)
 
   if (any(is.na(x))) {
@@ -37,4 +34,4 @@ setMethod("dbQuoteIdentifier", signature("DBIConnection", "SQL"), dbQuoteIdentif
 
 #' @rdname hidden_aliases
 #' @export
-setMethod("dbQuoteIdentifier", signature("DBIConnection", "Id"), dbQuoteIdentifier_DBIConnection)
+setMethod("dbQuoteIdentifier", signature("DBIConnection", "Id"), dbQuoteIdentifier_DBIConnection_Id)

tests/testthat/_snaps/00-Id.md

@@ -0,0 +1,15 @@
+# Id() requires a character vector
+
+    Code
+      Id(1)
+    Condition
+      Error:
+      ! All elements of `...` must be strings.
+
+# has a decent print method
+
+    Code
+      Id("a", "b")
+    Output
+      <Id> "a"."b"
+

tests/testthat/test-00-Id.R

@@ -0,0 +1,14 @@
+test_that("Id() requires a character vector", {
+  expect_snapshot(Id(1), error = TRUE)
+})
+
+test_that("has a decent print method", {
+  expect_snapshot(Id("a", "b"))
+})
+
+test_that("each element is quoted individually", {
+  expect_equal(
+    DBI::dbQuoteIdentifier(ANSI(), Id("a", "b.c")),
+    SQL('"a"."b.c"')
+  )
+})