diff --git a/bin/meta/hxlmetalib-tests.py b/bin/meta/hxlmetalib-tests.py
index 0dfbf68..9acf8fd 100755
--- a/bin/meta/hxlmetalib-tests.py
+++ b/bin/meta/hxlmetalib-tests.py
@@ -10,14 +10,41 @@
 import hxltype.usage
 import hxltype.weight
 
-hxltype.base.test()
+example_text = hxltype.data.emailDataHtype(value="Lorem ipsum")
+print('example_text', example_text.value)
+print('sys.getsizeof', sys.getsizeof(example_text))
 
-v1 = hxltype.data.DataHXLt(1, 1, 1)
-v2 = hxltype.data.DataHXLt2(1, 1, 1)
+example_number = hxltype.data.numberDataHtype(value=3.14)
+print('example_number', example_number.value)
+print('sys.getsizeof', sys.getsizeof(example_number))
 
-print('sys.getsizeof', sys.getsizeof(v1))
-print('sys.getsizeof2', sys.getsizeof(v2))
+example_url = hxltype.data.urlDataHtype(value="https://example.org")
+print('example_url', example_url.value)
+print('sys.getsizeof', sys.getsizeof(example_url))
 
-var1 = hxltype.data.DataHXLt(1, 1, 1)
-print('sys.getsizeofvar1', sys.getsizeof(var1))
-print(var1)
\ No newline at end of file
+example_email = hxltype.data.emailDataHtype(value="https://example.org")
+print('example_email', example_email.value)
+print('sys.getsizeof', sys.getsizeof(example_email))
+
+example_phone = hxltype.data.phoneDataHtype(value="+55 51 99999-9999")
+print('example_phone', example_phone.value)
+print('sys.getsizeof', sys.getsizeof(example_phone))
+print('sys.getsizeof', sys.getsizeof(example_email))
+
+example_date = hxltype.data.dateDataHtype(value="25/01/1986")
+print('example_date', example_date.value)
+print('sys.getsizeof', sys.getsizeof(example_date))
+
+#hxltype.base.test()
+
+# v1 = hxltype.data.DataHXLt(1, 1, 1)
+# v2 = hxltype.data.DataHXLt2(1, 1, 1)
+# v22 = hxltype.data.DataHXLt22(name=1, lat=1, lon=1)
+
+# print('sys.getsizeof', sys.getsizeof(v1))
+# print('sys.getsizeof2', sys.getsizeof(v2))
+# print('sys.getsizeof22', sys.getsizeof(v22))
+
+# var1 = hxltype.data.DataHXLt(1, 1, 1)
+# print('sys.getsizeofvar1', sys.getsizeof(var1))
+# print(var1)
\ No newline at end of file
diff --git a/bin/meta/hxltype/data.py b/bin/meta/hxltype/data.py
index 4c970c8..3ab80ee 100644
--- a/bin/meta/hxltype/data.py
+++ b/bin/meta/hxltype/data.py
@@ -6,6 +6,7 @@
 #  - github.com/HXLStandard/libhxl-python/blob/master/hxl/datatypes.py
 #  - github.com/HXLStandard/libhxl-python/blob/master/hxl/model.py
 #  - github.com/HXLStandard/libhxl-python/blob/master/hxl/validation.py
+#  - https://docs.google.com/spreadsheets/d/1En9FlmM8PrbTWgl3UHPF_MXnJ6ziVZFhBbojSJzBdLI/edit#gid=1881622062
 ### numpy
 #  - https://numpy.org/devdocs/user/basics.types.html
 #  - https://numpy.org/devdocs/reference/arrays.dtypes.html#arrays-dtypes
@@ -24,18 +25,58 @@
 # - https://stackoverflow.com/questions/47955263/what-are-data-classes-and-how-are-they-different-from-common-classes
 # - https://www.programiz.com/python-programming/multiple-inheritance
 # - https://medium.com/@jacktator/dataclass-vs-namedtuple-vs-object-for-performance-optimization-in-python-691e234253b9
+# - https://stackoverflow.com/questions/50180735/how-can-dataclasses-be-made-to-work-better-with-slots
 
 from dataclasses import dataclass
 
 
-@dataclass()
-class DataHXLt:
-    name: str
-    lon: float
-    lat: float
+@dataclass(init=True, repr=True, eq=True)
+class DataHtype:
+    name: str = None
+    dataType: str = None
+    storageType: str = None
+    levelType: str = None
+    usageType: str = None
+    weightType: str = None
+    value: str = None
 
-@dataclass()
-class DataHXLt2:
-    name: str
-    lon: float
-    lat: float
+# @dataclass(init=True)
+# class DataHXLt2:
+#     __slots__ = ['name', 'lon', 'lat']
+#     name: str
+#     lon: float
+#     lat: float
+
+# @dataclass(init=True)
+# class DataHXLt22:
+#     __slots__ = ['name', 'lon', 'lat']
+#     name: str
+#     lon: float
+#     lat: float
+
+# HXL Standard / HXL core schema / Data types
+# @see https://docs.google.com/spreadsheets/d/1En9FlmM8PrbTWgl3UHPF_MXnJ6ziVZFhBbojSJzBdLI/edit#gid=1881622062
+
+class textDataHtype(DataHtype):
+    def __post_init__(self):
+        self.dataType = "text"
+
+class numberDataHtype(DataHtype):
+    def __post_init__(self):
+        self.dataType = "number"
+
+class urlDataHtype(DataHtype):
+    def __post_init__(self):
+        self.dataType = "url"
+
+class emailDataHtype(DataHtype):
+    def __post_init__(self):
+        self.dataType = "email"
+
+class phoneDataHtype(DataHtype):
+    def __post_init__(self):
+        self.dataType = "phone"
+
+class dateDataHtype(DataHtype):
+    def __post_init__(self):
+        self.dataType = "date"
\ No newline at end of file