python - Sqlalchemy if table does not exist -

i wrote module create empty database file

def create_database():     engine = create_engine("sqlite:///myexample.db", echo=true)     metadata = metadata(engine)     metadata.create_all() 

but in function, want open myexample.db database, , create tables if doesn't have table.

eg of first, subsequent table create be:

table(variable_tablename, metadata,        column('id', integer, primary_key=true, nullable=false),        column('date', date),        column('volume', float)) 

(since empty database, have no tables in it, subsequently, can add more tables it. thats i'm trying say.)

any suggestions?

i've managed figure out intended do. used engine.dialect.has_table(engine, variable_tablename) check if database has table inside. if doesn't, proceed create table in database.

sample code:

engine = create_engine("sqlite:///myexample.db")  # access db engine if not engine.dialect.has_table(engine, variable_tablename):  # if table don't exist, create.     metadata = metadata(engine)     # create table appropriate columns     table(variable_tablename, metadata,           column('id', integer, primary_key=true, nullable=false),            column('date', date), column('country', string),           column('brand', string), column('price', float),     # implement creation     metadata.create_all() 

this seems giving me i'm looking for.