diff --git a/stix2/datastore/relational_db/input_creation.py b/stix2/datastore/relational_db/input_creation.py
index 12dcb966..407b195c 100644
--- a/stix2/datastore/relational_db/input_creation.py
+++ b/stix2/datastore/relational_db/input_creation.py
@@ -2,7 +2,7 @@
 
 from stix2.datastore.relational_db.add_method import add_method
 from stix2.datastore.relational_db.utils import (
-    SCO_COMMON_PROPERTIES, SDO_COMMON_PROPERTIES, canonicalize_table_name,
+    SCO_COMMON_PROPERTIES, SDO_COMMON_PROPERTIES, canonicalize_table_name, shorten_extension_definition_id
 )
 from stix2.properties import (
     BinaryProperty, BooleanProperty, DictionaryProperty,
@@ -153,9 +153,10 @@ def generate_insert_information(self, name, stix_object, data_sink=None, table_n
     for ex_name, ex in stix_object["extensions"].items():
         # ignore new extensions - they have no properties
         if ex.extension_type is None or not ex.extension_type.startswith("new"):
-            if ex_name.startswith("extension-definition"):
-                ex_name = ex_name[0:30]
-                ex_name = ex_name.replace("extension-definition-", "ext_def")
+            if ex_name.startswith("extension-definition--"):
+                # ex_name = ex_name[0:30]
+                # ex_name = ex_name.replace("extension-definition-", "ext_def")
+                ex_name = shorten_extension_definition_id(ex_name)
             bindings = {
                 "id": stix_object["id"],
                 "ext_table_name": canonicalize_table_name(ex_name, schema_name),
@@ -510,9 +511,10 @@ def generate_insert_for_sub_object(
         bindings["id"] = foreign_key_value
     if parent_table_name and (not is_extension or level > 0):
         type_name = parent_table_name + "_" + type_name
-    if type_name.startswith("extension-definition"):
-        type_name = type_name[0:30]
-        type_name = type_name.replace("extension-definition-", "ext_def")
+    if type_name.startswith("extension-definition--"):
+        # type_name = type_name[0:30]
+        # type_name = type_name.replace("extension-definition-", "ext_def")
+        type_name = shorten_extension_definition_id(type_name)
     sub_insert_statements = list()
     for name, prop in stix_object._properties.items():
         if name in stix_object:
diff --git a/stix2/datastore/relational_db/table_creation.py b/stix2/datastore/relational_db/table_creation.py
index b9ca5641..14ffe663 100644
--- a/stix2/datastore/relational_db/table_creation.py
+++ b/stix2/datastore/relational_db/table_creation.py
@@ -7,7 +7,7 @@
 from stix2.datastore.relational_db.utils import (
     SCO_COMMON_PROPERTIES, SDO_COMMON_PROPERTIES, canonicalize_table_name,
     determine_column_name, determine_sql_type_from_stix, flat_classes,
-    get_stix_object_classes,
+    get_stix_object_classes, shorten_extension_definition_id
 )
 from stix2.properties import (
     BinaryProperty, BooleanProperty, DictionaryProperty,
@@ -800,9 +800,10 @@ def generate_object_table(
     else:
         table_name = stix_object_class.__name__
     # avoid long table names
-    if table_name.startswith("extension-definition"):
-        table_name = table_name[0:30]
-        table_name = table_name.replace("extension-definition-", "ext_def")
+    if table_name.startswith("extension-definition--"):
+        # table_name = table_name[0:30]
+        # table_name = table_name.replace("extension-definition-", "ext_def")
+        table_name = shorten_extension_definition_id(table_name)
     if parent_table_name:
         table_name = parent_table_name + "_" + table_name
     if is_embedded_object:
diff --git a/stix2/datastore/relational_db/utils.py b/stix2/datastore/relational_db/utils.py
index 65257426..43ca4dc4 100644
--- a/stix2/datastore/relational_db/utils.py
+++ b/stix2/datastore/relational_db/utils.py
@@ -109,10 +109,10 @@ def table_name_for(stix_type_or_class):
     # Applies to registered extension-definition style extensions only.
     # Their "_type" attribute is actually set to the extension definition ID,
     # rather than a STIX type.
-    if table_name.startswith("extension-definition"):
-        table_name = table_name[0:30]
-        table_name = table_name.replace("extension-definition-", "ext_def")
-
+    if table_name.startswith("extension-definition--"):
+        # table_name = table_name[0:30]
+        # table_name = table_name.replace("extension-definition-", "ext_def")
+        table_name = shorten_extension_definition_id(table_name)
     table_name = canonicalize_table_name(table_name)
     return table_name
 
@@ -169,3 +169,12 @@ def determine_column_name(cls_or_inst):  # noqa: F811
         return "string_value"
     elif is_class_or_instance(cls_or_inst, TimestampProperty):
         return "timestamp_value"
+
+
+def shorten_extension_definition_id(id):
+    id_parts = id.split("--")
+    uuid_parts = id_parts[1].split("-")
+    shortened_part = ""
+    for p in uuid_parts:
+        shortened_part = shortened_part + p[0] + p[-1]
+    return "ext_def_" + shortened_part
\ No newline at end of file