houqp commented on a change in pull request #13278:
URL: https://github.com/apache/airflow/pull/13278#discussion_r548609907
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File path: airflow/utils/types.py
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@@ -16,8 +16,31 @@
# under the License.
import enum
+from sqlalchemy.types import TypeDecorator, String
-class DagRunType(str, enum.Enum):
+
+class EnumString(TypeDecorator):
+ """
+ Declare db column with this type to make the column compatible with string
+ and string based enum values when building the sqlalchemy ORM query. It can
+ be used just like sqlalchemy.types.String, for example:
+
+ ```
+ class Table(Base):
+ __tablename__ = "t"
+ run_type = Column(EnumString(50), nullable=False)
+ ```
+ """
+ impl = String
+
+ def process_bind_param(self, value, dialect):
+ if isinstance(value, enum.Enum):
+ return value.value
+ else:
+ return value
+
+
+class DagRunType(enum.Enum):
Review comment:
i had the same question initially, i am curious about the reason for
picking string for column type here. as far as i know, the biggest pain with
using enum in postgres was schema evolution, i.e. adding new value to enum. I
have heard postgres 9.x has made some improvements around that area.
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