diff --git a/NEWS.md b/NEWS.md
index 44565546d..d4c0c0e9a 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,15 @@
 # teal.data 0.6.0.9006
 
+### Enhancements
+
+- `datanames()`
+    - if `join_keys` are provided, the `datanames()` are now sorted in topological way (`Kahn` algorithm),
+    which means the parent dataset always precedes the child dataset.
+    - are extended by the parent dataset name, if one of the child dataset exist in `datanames()` and
+    the connection between child-parent is set through `join_keys` and `parent` exist in `teal_data` environment.
+    - do not allow to set a dataset name that do not exist in `teal_data` environment.
+    - `teal_data` no longer set default `datanames()` based on `join_keys` names - it uses only data names.
+
 # teal.data 0.6.0
 
 ### Enhancements
diff --git a/R/join_keys.R b/R/join_keys.R
index 47fb97836..1798a46af 100644
--- a/R/join_keys.R
+++ b/R/join_keys.R
@@ -142,6 +142,7 @@ join_keys.teal_data <- function(...) {
 #' join_keys(td)
 `join_keys<-.teal_data` <- function(x, value) {
   join_keys(x@join_keys) <- value
+  datanames(x) <- x@datanames # datanames fun manages some exceptions
   x
 }
 
diff --git a/R/teal_data-class.R b/R/teal_data-class.R
index 542ee76bb..3015797b9 100644
--- a/R/teal_data-class.R
+++ b/R/teal_data-class.R
@@ -60,7 +60,7 @@ setClass(
 new_teal_data <- function(data,
                           code = character(0),
                           join_keys = join_keys(),
-                          datanames = union(names(data), names(join_keys))) {
+                          datanames = names(data)) {
   checkmate::assert_list(data)
   checkmate::assert_class(join_keys, "join_keys")
   if (is.null(datanames)) datanames <- character(0) # todo: allow to specify
@@ -82,6 +82,8 @@ new_teal_data <- function(data,
   new_env <- rlang::env_clone(list2env(data), parent = parent.env(.GlobalEnv))
   lockEnvironment(new_env, bindings = TRUE)
 
+  datanames <- .get_sorted_datanames(datanames = datanames, join_keys = join_keys, env = new_env)
+
   methods::new(
     "teal_data",
     env = new_env,
diff --git a/R/teal_data-datanames.R b/R/teal_data-datanames.R
index 929f09eb1..d32727859 100644
--- a/R/teal_data-datanames.R
+++ b/R/teal_data-datanames.R
@@ -42,7 +42,7 @@ setMethod("datanames", signature = "qenv.error", definition = function(x) {
 setGeneric("datanames<-", function(x, value) standardGeneric("datanames<-"))
 setMethod("datanames<-", signature = c("teal_data", "character"), definition = function(x, value) {
   checkmate::assert_subset(value, names(x@env))
-  x@datanames <- value
+  x@datanames <- .get_sorted_datanames(datanames = value, join_keys = x@join_keys, env = x@env)
   methods::validObject(x)
   x
 })
@@ -50,3 +50,19 @@ setMethod("datanames<-", signature = c("qenv.error", "character"), definition =
   methods::validObject(x)
   x
 })
+
+
+#' @keywords internal
+.get_sorted_datanames <- function(datanames, join_keys, env) {
+  child_parent <- sapply(
+    datanames,
+    function(name) parent(join_keys, name),
+    USE.NAMES = TRUE,
+    simplify = FALSE
+  )
+
+  union(
+    intersect(unlist(topological_sort(child_parent)), ls(env)),
+    datanames
+  )
+}
diff --git a/inst/WORDLIST b/inst/WORDLIST
index f53064cb2..6860ac2d2 100644
--- a/inst/WORDLIST
+++ b/inst/WORDLIST
@@ -3,6 +3,7 @@ CDISC
 Forkers
 Getter
 Hoffmann
+Kahn
 ORCID
 Reproducibility
 formatters
diff --git a/man/new_teal_data.Rd b/man/new_teal_data.Rd
index 176a04ae5..4ddc43c95 100644
--- a/man/new_teal_data.Rd
+++ b/man/new_teal_data.Rd
@@ -8,7 +8,7 @@ new_teal_data(
   data,
   code = character(0),
   join_keys = join_keys(),
-  datanames = union(names(data), names(join_keys))
+  datanames = names(data)
 )
 }
 \arguments{
diff --git a/tests/testthat/test-datanames.R b/tests/testthat/test-datanames.R
index 68966006f..e0c99bb63 100644
--- a/tests/testthat/test-datanames.R
+++ b/tests/testthat/test-datanames.R
@@ -41,3 +41,97 @@ testthat::test_that("datanames<- called on qenv.error does not change qenv.error
   qec <- qe
   testthat::expect_identical(qe, qec)
 })
+
+# topological_order ----
+
+testthat::test_that("datanames are set in topological order in constructor if join_keys are specified", {
+  data <-
+    teal_data(b = data.frame(), a = data.frame(), join_keys = join_keys(join_key("a", "b", "id")))
+  testthat::expect_identical(
+    datanames(data),
+    c("a", "b")
+  )
+})
+
+testthat::test_that("datanames return parent if in constructor it was provided in join_keys and exists in env", {
+  data <-
+    teal_data(b = data.frame(), a = data.frame(), join_keys = join_keys(join_key("a", "b", "id")))
+  datanames(data) <- "b"
+  testthat::expect_identical(
+    datanames(data),
+    c("a", "b")
+  )
+})
+
+testthat::test_that(
+  "datanames do not return parent if in constructor it was provided in join_keys but do not exists in env",
+  {
+    data <-
+      teal_data(b = data.frame(), join_keys = join_keys(join_key("a", "b", "id")))
+    testthat::expect_identical(
+      datanames(data),
+      "b"
+    )
+  }
+)
+
+testthat::test_that("datanames return topological order of datasets once join_keys are specified", {
+  data <- within(teal_data(), {
+    ADTTE <- teal.data::rADTTE # nolint: object_name.
+    iris <- iris
+    ADSL <- teal.data::rADSL # nolint: object_name.
+  })
+  datanames(data) <- c("ADTTE", "iris", "ADSL")
+  join_keys(data) <- default_cdisc_join_keys[c("ADSL", "ADTTE")]
+  testthat::expect_identical(
+    datanames(data),
+    c("ADSL", "ADTTE", "iris")
+  )
+})
+
+testthat::test_that("datanames return topological order of datasets after datanames are called after join_keys", {
+  data <- within(teal_data(), {
+    ADTTE <- teal.data::rADTTE # nolint: object_name.
+    iris <- iris
+    ADSL <- teal.data::rADSL # nolint: object_name.
+  })
+
+  join_keys(data) <- default_cdisc_join_keys[c("ADSL", "ADTTE")]
+  datanames(data) <- c("ADTTE", "iris", "ADSL")
+
+  testthat::expect_identical(
+    datanames(data),
+    c("ADSL", "ADTTE", "iris")
+  )
+})
+
+
+testthat::test_that("datanames return parent if join_keys were provided and parent exists in env", {
+  data <- within(teal_data(), {
+    ADTTE <- teal.data::rADTTE # nolint: object_name.
+    iris <- iris
+    ADSL <- teal.data::rADSL # nolint: object_name.
+  })
+
+  join_keys(data) <- default_cdisc_join_keys[c("ADSL", "ADTTE")]
+  datanames(data) <- c("ADTTE", "iris")
+
+  testthat::expect_identical(
+    datanames(data),
+    c("ADSL", "ADTTE", "iris")
+  )
+})
+
+testthat::test_that("datanames do not return parent if join_keys were provided and parent did not exists in env", {
+  data <- teal_data(
+    ADTTE = teal.data::rADTTE, # nolint: object_name.
+    iris = iris
+  )
+
+  join_keys(data) <- default_cdisc_join_keys[c("ADSL", "ADTTE")]
+
+  testthat::expect_identical(
+    datanames(data),
+    c("ADTTE", "iris")
+  )
+})
diff --git a/tests/testthat/test-teal_data.R b/tests/testthat/test-teal_data.R
index 72c7e7e3b..8391f72e2 100644
--- a/tests/testthat/test-teal_data.R
+++ b/tests/testthat/test-teal_data.R
@@ -28,19 +28,25 @@ testthat::test_that("teal_data initializes teal_data object with @datanames take
   )
 })
 
-testthat::test_that("teal_data initializes teal_data object with @datanames taken from passed join_keys", {
-  testthat::expect_identical(
-    teal_data(join_keys = join_keys(join_key("parent", "child", "id")))@datanames,
-    c("parent", "child")
-  )
-})
+testthat::test_that(
+  "teal_data initializes teal_data object without @datanames taken from join_keys if objects did not exist in env",
+  {
+    testthat::expect_identical(
+      datanames(teal_data(join_keys = join_keys(join_key("parent", "child", "id")))),
+      character(0)
+    )
+  }
+)
 
-testthat::test_that("teal_data initializes teal_data object with @datanames taken from join_keys and passed objects", {
-  testthat::expect_identical(
-    teal_data(iris = iris, join_keys = join_keys(join_key("parent", "child", "id")))@datanames,
-    c("iris", "parent", "child")
-  )
-})
+testthat::test_that(
+  "teal_data initializes teal_data object with @datanames taken only from passed objects and not join_keys",
+  {
+    testthat::expect_identical(
+      datanames(teal_data(iris = iris, join_keys = join_keys(join_key("parent", "child", "id")))),
+      "iris"
+    )
+  }
+)
 
 
 testthat::test_that("teal_data returns teal_data when data passed as named list", {