i started using sqlalchemy creating tables in postgresql , experienced folks here:
i have problem initializing table data read file. here's example of tried, in part based on this post.
schema = "spectr" # schema exists in database connstr = "postgresql+psycopg2://postgres:postgres@localhost/postgres" mymetadata = metadata(schema=schema) base = declarative_base(metadata=mymetadata) engine = create_engine(connstr, echo=true) class file(base): """ file metadata """ __tablename__ = "files" id = column(integer, primary_key=true) altitude = column(numeric(precision=6, scale=1)) average_ref = column(integer, nullable=false) average_target = column(integer, nullable=false) def __init__(self, filename=none): if filename != none: dic = read_sed(filename) k in file.__table__.columns.keys(): if k != 'id': file.k = dic.get(k, none) # 'read_sed' function returns dictionary of data in filename file().__table__.create(engine, checkfirst=true) file = file(filename) session = sessionmaker(bind=engine) session = session() session.add(file) session.commit() # point error since file empty , many columns nullable=false. here's end of error output:
sqlalchemy.exc.integrityerror: (psycopg2.integrityerror) null value in column "average_ref" violates not-null constraint detail: failing row contains (1, null, null, null). [sql: 'insert spectro.files (altitude, average_ref, average_target) values (%(altitude)s, %(average_ref)s, %(average_target)s) returning spectro.files.id'] [parameters: {'average_target': none, 'average_ref': none, 'altitude': none}] any idea wrong?
thanks lot help.
i not sure line supposed do:
file.k = dic.get(k, none) as looks, set property k (not value of variable k) file class (not instance). assuming want set field such altitude, average_ref, average_target in loaded file on current instance of file, should set them on self using setattr instead:
setattr(self, k, dic.get(k, none)) also if dic instance of dict, , none redundant , can use setattr(self, k, dic.get(k))
