Added Id method for dbExistsTable to address issue #498

DESCRIPTION

@@ -103,6 +103,7 @@ Collate:
     'dbDataType_SQLiteConnection.R'
     'dbDataType_SQLiteDriver.R'
     'dbDisconnect_SQLiteConnection.R'
+    'dbExistsTable_SQLiteConnection_Id.R'
     'dbExistsTable_SQLiteConnection_character.R'
     'dbFetch_SQLiteResult.R'
     'dbGetException_SQLiteConnection.R'

R/dbExistsTable_SQLiteConnection_Id.R

@@ -0,0 +1,27 @@
+#' @rdname SQLiteConnection-class
+#' @usage NULL
+dbExistsTable_SQLiteConnection_Id <- function(conn, name, ...) {
+  stopifnot(is(name, "Id"))
+
+  id <- as.list(dbUnquoteIdentifier(conn, dbQuoteIdentifier(conn, name))[[1]]@name)
+  schema <- id$schema
+  table <- id$table
+
+  if (!is.null(schema)) {
+    schemas <- dbGetQuery(conn, "SELECT name FROM pragma_database_list;")$name
+
+    if (!(schema %in% schemas)) {
+      return(FALSE)
+    }
+  }
+
+  sql <- sqliteListTablesQuery(conn, schema, SQL("$name"))
+  rs <- dbSendQuery(conn, sql)
+  dbBind(rs, list(name = tolower(table)))
+  on.exit(dbClearResult(rs), add = TRUE)
+
+  nrow(dbFetch(rs, 1L)) > 0
+}
+#' @rdname SQLiteConnection-class
+#' @export
+setMethod("dbExistsTable", c("SQLiteConnection", "Id"), dbExistsTable_SQLiteConnection_Id)