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from sqlalchemy import create_engine, MetaData, ForeignKey
engine = create_engine("mysql://user:passwd@localhost/shema", echo=False)
meta = MetaData(engine, True)
conn = engine.connect()
tb_list = meta.tables["tb_list"]
tb_data = meta.tables["tb_data"]
tb_list.c.i_data.append_foreign_key( ForeignKey(tb_data.c.i_id) )
q = tb_list.outerjoin(tb_data).select()
res = conn.execute(q)
And now, how can I get columns type of query result res
One of decisions:
res._key_cache[ col_name ][0]
Do you know something else ?
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It returns exactly one result or raise an exception. It applies one or more ORDER BY criterion to the query and returns the newly resulting Query. It performs a bulk update query and updates rows matched by this query in the database.
To access the column names we can use the method keys() on the result. It returns a list of column names. Since, we queried only three columns, we can view the same columns on the output as well.
PickleType. Holds Python objects, which are serialized using pickle. SchemaType. Mark a type as possibly requiring schema-level DDL for usage.
_sa_instance_state is a non-database-persisted value used by SQLAlchemy internally (it refers to the InstanceState for the instance.
you'd say:
types = [col.type for col in q.columns]
the (compiled) statement is on the result too if you feel like digging:
types = [col.type for col in res.context.compiled.statement.columns]
if you want the DBAPI version of the types, which is a little more varied based on DBAPI:
types = [elem[1] for elem in res.cursor.description]
maybe we'll look into adding this kind of metadata more directly to the ResultProxy.
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