Sqlalchemy if table does not exist

Question

I wrote a module which is to create an empty database file

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


        

Answer 1

engine.dialect.has_table does not work for me on cx_oracle. I am getting AttributeError: 'OracleDialect_cx_oracle' object has no attribute 'default_schema_name'

I wrote a workaround function:

from sqlalchemy.engine.base import Engine  
def orcl_tab_or_view_exists(in_engine: Engine, in_object: str,  in_object_name: str,)-> bool:
    """Checks if Oracle table exists in current in_engine connection

    in_object: 'table' | 'view'

    in_object_name: table_name | view_name
      """
    obj_query = """SELECT {o}_name FROM all_{o}s WHERE owner = SYS_CONTEXT ('userenv', 'current_schema') AND {o}_name = '{on}'
    """.format(o=in_object, on=in_object_name.upper())
    with in_engine.connect() as connection:
        result = connection.execute(obj_query)
    return len(list(result)) > 0