kaxil commented on a change in pull request #9973:
URL: https://github.com/apache/airflow/pull/9973#discussion_r629693129
##########
File path:
airflow/migrations/versions/bbf4a7ad0465_remove_id_column_from_xcom.py
##########
@@ -35,6 +37,61 @@
depends_on = None
+def get_table_constraints(conn, table_name):
+ """
+ This function return primary and unique constraint
+ along with column name. some tables like task_instance
+ is missing primary key constraint name and the name is
+ auto-generated by sql server. so this function helps to
+ retrieve any primary or unique constraint name.
+ :param conn: sql connection object
+ :param table_name: table name
+ :return: a dictionary of ((constraint name, constraint type), column name)
of table
+ :rtype: defaultdict(list)
+ """
+ query = """SELECT tc.CONSTRAINT_NAME , tc.CONSTRAINT_TYPE, ccu.COLUMN_NAME
+ FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS tc
+ JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE AS ccu ON
ccu.CONSTRAINT_NAME = tc.CONSTRAINT_NAME
+ WHERE tc.TABLE_NAME = '{table_name}' AND
+ (tc.CONSTRAINT_TYPE = 'PRIMARY KEY' or UPPER(tc.CONSTRAINT_TYPE) =
'UNIQUE')
+ """.format(
+ table_name=table_name
+ )
+ result = conn.execute(query).fetchall()
+ constraint_dict = defaultdict(list)
+ for constraint, constraint_type, column in result:
+ constraint_dict[(constraint, constraint_type)].append(column)
+ return constraint_dict
+
+
+def drop_column_constraints(operator, column_name, constraint_dict):
+ """
+ Drop a primary key or unique constraint
+ :param operator: batch_alter_table for the table
Review comment:
```suggestion
Drop a primary key or unique constraint
:param operator: batch_alter_table for the table
```
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