How to create a temporary table for an existing table with sqlalchemy?

Question

I have a table(in mysql-server) associated with the following class:

class Number(Base):
    __table_name__ = 'number'
    col0 = Column(...) # PRIMARY KEY
    col1 = Column(...)
    col2 = Column(...)
    col3 = Column(...)

I want to create a temporary table for this number table when the program starts, this temporary table looks like:

class tempNumber(Base):
      __table_name__ = 'temp_number'
      col0 = Column(...) # direct from Number.col0
      col1 = Column(...) # from Number.col1, but will be modified, for example tempNumber.col1 = Number.col1.replace(' ','')

I also tried to add the following line to class Number:

__table_args__ = {'prefixes': ['TEMPORARY']}

but my python programm told me that table temp_number doesn't exist.

and one more question is, how to copy the data fast? because there are lots of rows in table number.

Answer 1

1. Does the temp_number table actually exist in the underlying database?

2. Generally, copying data from one table to another quickly isn't done through sqlalchemy , which has significant overhead in this type of task. Instead, it will vary depending on your underlying database.

For example, here's how one would do it in MySQL . Here's a way to do it with PostgreSQL. However, this usually doesn't copy things like indexes. That, you'll have to setup manually, via your database driver.