Column length not returned for NVARCHAR columns when inspecting a HANA Cloud view
JanFetzer opened this issue · comments
Hi,
I am using sqlalchemy.engine.reflection.Inspector to relect view column of a database view in HANA Cloud.
inspector = reflection.Inspector.from_engine(engine)
colTypes = inspector.get_columns(table_name="myView", schema="mySchema")
while the view actually has fields id & user of data type NVARCHAR with length =5000 and 255 respectively, what I get for colTypes is
[{'name': 'id',
'default': None,
'nullable': True,
'comment': None,
'type': NVARCHAR()},
{'name': 'user',
'default': None,
'nullable': True,
'comment': None,
'type': NVARCHAR()}]
The SQL generated is this (I inspected it with echo=True when creating the engine object):
SELECT COLUMN_NAME, DATA_TYPE_NAME, DEFAULT_VALUE, IS_NULLABLE, LENGTH, SCALE, COMMENTS FROM (
SELECT SCHEMA_NAME, TABLE_NAME, COLUMN_NAME, POSITION, DATA_TYPE_NAME, DEFAULT_VALUE, IS_NULLABLE,
LENGTH, SCALE, COMMENTS FROM SYS.TABLE_COLUMNS UNION ALL SELECT SCHEMA_NAME, VIEW_NAME AS TABLE_NAME,
COLUMN_NAME, POSITION, DATA_TYPE_NAME, DEFAULT_VALUE, IS_NULLABLE, LENGTH, SCALE, COMMENTS FROM
SYS.VIEW_COLUMNS) AS COLUMS WHERE SCHEMA_NAME=? AND TABLE_NAME=? ORDER BY POSITION
and it correctly contains the column length (see screenshot), but the information gets lost while passing it on to SQLAlchemy.
As a result, I cannot e.g. generate a table with same column type specification, since if I specify its column dtypes as NVARCHAR(), the default field length is 1, and my data will not fit
Actual view column types on DB
Result of relevant part of above SQL:
