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| -rw-r--r-- | lib/sqlalchemy/sql/sqltypes.py | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py index b8c8c8116..7a3c50549 100644 --- a/lib/sqlalchemy/sql/sqltypes.py +++ b/lib/sqlalchemy/sql/sqltypes.py @@ -1911,6 +1911,22 @@ class JSON(Indexable, TypeEngine): session.add_all([obj1, obj2]) session.commit() + In order to set JSON NULL as a default value for a column, the most + transparent method is to use :func:`.text`:: + + Table( + 'my_table', metadata, + Column('json_data', JSON, default=text("'null'")) + ) + + While it is possible to use :attr:`.JSON.NULL` in this context, the + :attr:`.JSON.NULL` value will be returned as the value of the column, + which in the context of the ORM or other repurposing of the default + value, may not be desirable. Using a SQL expression means the value + will be re-fetched from the database within the context of retrieving + generated defaults. + + """ def __init__(self, none_as_null=False): |