alembic note.txt

Alembic is a database migration tool which help to making changes in existing database
for using alembic we need to intialize the alemibic my using 
alembic init [name of the folder]
then for setting your database you neeed to making somes changes in evn.py file which would inside alembic file
and then changes somthin in alembic.ini file, after that alembic is ready to roll.
how to use alembic 
before creating table you neeb to create revison of that table by using following commond

alembic revision -m "any message " like alembic revision -m "create posts table"

how to use alembic upgrade ? use the following commond

alembic upgrade [revison ID] like alembic upgrade b6bf507584c6 we can also use alembic upgrade head if our current revison is a head


to check current revison use 
alembic current
for checking leatest revison we follwing command

alembic head


for downgradeing we use folloing command

alembic downgrade [revison]
of 
alemic downgrade -1 or -2 any number we want
for checking history in alembic use following command
alembic history


alembic has a --autogenerate which take a look at models file and check the diffrent and then it will fullfil those 
for using this we use 
alembic revision --autogenerate -m "auto vote" or message
after that use alembic upgrade head