crate · amotl · Jul 1, 2025 · Jun 27, 2025
diff --git a/CHANGES.md b/CHANGES.md
@@ -1,6 +1,7 @@
 # Changelog
 
 ## Unreleased
+- DMS: Added option `ignore_ddl` to ignore DDL events
 
 ## 2025/06/23 v0.0.23
 - Dependencies: Migrated from `zyp` to `tikray`. It's effectively the

diff --git a/src/commons_codec/model.py b/src/commons_codec/model.py
@@ -90,6 +90,10 @@ class SQLOperation:
     parameters: t.Optional[t.Union[t.Mapping[str, t.Any], t.List[t.Mapping[str, t.Any]]]] = None
 
 
+class SkipOperation(Exception):
+    pass
+
+
 @define
 class SQLParameterizedClause:
     """

diff --git a/src/commons_codec/transform/aws_dms.py b/src/commons_codec/transform/aws_dms.py
@@ -11,6 +11,7 @@
     ColumnType,
     ColumnTypeMapStore,
     PrimaryKeyStore,
+    SkipOperation,
     SQLOperation,
     SQLParameterizedSetClause,
     SQLParameterizedWhereClause,
@@ -83,13 +84,16 @@ def __init__(
         self.primary_keys: t.List[str] = self.container.primary_keys[self.address]
         self.column_types: t.Dict[str, ColumnType] = self.container.column_types[self.address]
 
-        pks = self.control.get("table-def", {}).get("primary-key", [])
-        for pk in pks:
-            if pk not in self.primary_keys:
-                self.primary_keys.append(pk)
+        if not self.container.ignore_ddl:
+            pks = self.control.get("table-def", {}).get("primary-key", [])
+            for pk in pks:
+                if pk not in self.primary_keys:
+                    self.primary_keys.append(pk)
 
     def to_sql(self) -> SQLOperation:
         if self.operation == "create-table":
+            if self.container.ignore_ddl:
+                raise SkipOperation("Ignoring DMS DDL event: create-table")
             return SQLOperation(
                 f"CREATE TABLE IF NOT EXISTS {self.address.fqn} ("
                 f"{self.PK_COLUMN} OBJECT(STRICT){self.pk_clause()}, "
@@ -98,6 +102,8 @@ def to_sql(self) -> SQLOperation:
             )
 
         elif self.operation == "drop-table":
+            if self.container.ignore_ddl:
+                raise SkipOperation("Ignoring DMS DDL event: drop-table")
             # Remove cached schema information by restoring original so a future CREATE starts clean.
             self.container.primary_keys[self.address] = self.container.primary_keys_caller.get(self.address, [])
             self.container.column_types[self.address] = self.container.column_types_caller.get(self.address, {})
@@ -249,9 +255,11 @@ def __init__(
         self,
         primary_keys: PrimaryKeyStore = None,
         column_types: ColumnTypeMapStore = None,
+        ignore_ddl: bool = False,
     ):
         self.primary_keys = primary_keys or PrimaryKeyStore()
         self.column_types = column_types or ColumnTypeMapStore()
+        self.ignore_ddl = ignore_ddl
 
         # Store caller-provided schema information to restore this state on `DROP TABLE` operations.
         self.primary_keys_caller = copy.deepcopy(self.primary_keys)

diff --git a/tests/transform/test_aws_dms.py b/tests/transform/test_aws_dms.py
@@ -6,7 +6,14 @@
 import pytest
 
 from commons_codec.exception import MessageFormatError, UnknownOperationError
-from commons_codec.model import ColumnType, ColumnTypeMapStore, SQLOperation, TableAddress
+from commons_codec.model import (
+    ColumnType,
+    ColumnTypeMapStore,
+    PrimaryKeyStore,
+    SkipOperation,
+    SQLOperation,
+    TableAddress,
+)
 from commons_codec.transform.aws_dms import DMSTranslatorCrateDB
 
 RECORD_INSERT = {"age": 31, "attributes": {"baz": "qux"}, "id": 46, "name": "Jane"}
@@ -179,7 +186,7 @@
 @pytest.fixture
 def cdc():
     """
-    Provide fresh translator instance.
+    Provide a regular translator instance.
     """
     column_types = ColumnTypeMapStore().add(
         table=TableAddress(schema="public", table="foo"),
@@ -189,6 +196,22 @@ def cdc():
     return DMSTranslatorCrateDB(column_types=column_types)
 
 
+@pytest.fixture
+def cdc_without_ddl():
+    """
+    Provide a translator instance that ignores DDL events.
+    """
+    ta = TableAddress(schema="public", table="foo")
+    primary_keys = PrimaryKeyStore()
+    primary_keys[ta] = {"name": "id", "type": "INTEGER"}
+    column_types = ColumnTypeMapStore().add(
+        table=ta,
+        column="attributes",
+        type_=ColumnType.MAP,
+    )
+    return DMSTranslatorCrateDB(column_types=column_types, ignore_ddl=True)
+
+
 def test_decode_cdc_unknown_source(cdc):
     with pytest.raises(MessageFormatError) as ex:
         cdc.to_sql(MSG_UNKNOWN_SHAPE)
@@ -239,6 +262,18 @@ def test_decode_cdc_sql_ddl_regular_drop(cdc):
     )
 
 
+def test_decode_cdc_sql_without_ddl_regular_create(cdc_without_ddl):
+    with pytest.raises(SkipOperation) as ex:
+        cdc_without_ddl.to_sql(MSG_CONTROL_CREATE_TABLE)
+    assert ex.match("Ignoring DMS DDL event: create-table")
+
+
+def test_decode_cdc_sql_without_ddl_regular_drop(cdc_without_ddl):
+    with pytest.raises(SkipOperation) as ex:
+        cdc_without_ddl.to_sql(MSG_CONTROL_DROP_TABLE)
+    assert ex.match("Ignoring DMS DDL event: drop-table")
+
+
 def test_decode_cdc_sql_ddl_awsdms(cdc):
     assert cdc.to_sql(MSG_CONTROL_AWSDMS) == SQLOperation(
         statement="CREATE TABLE IF NOT EXISTS dms.awsdms_apply_exceptions "
-Original file line number
+Diff line change
@@ Expand Up / @@ -90,6 +90,10 @@ class SQLOperation: @@
         parameters: t.Optional[t.Union[t.Mapping[str, t.Any], t.List[t.Mapping[str, t.Any]]]] = None
+    class SkipOperation(Exception):
+        pass
     @define
     class SQLParameterizedClause:
         """
@@ Expand Down @@