SQLAlchemy Turns Python Objects Into Database Entries
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- Опубликовано: 25 окт 2022
- Today we learn about SQLAlchemy, which is an SQL Toolkit and ORM that allows us to map Python classes to database tables.
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Very clean and easy to understand, thanks for the video.
Just a small hint: at 18:51 you couldn't see the table, bc the database windows won't refresh automatically in PyCharm. You have to click the refresh button at the top of the panel (third symbol in ur case). Then it will show the additionally created tables.
One of the best channels in youtube! Thanks for your work!!!
Ive watched this video sooooo many times! Brilliant tutorial on using SQLAlchemy to abstract SQL from python. I also loved your CLASSES video! Its helped me develop my code so much faster. Cheers dude!"
Very great article. Short, distinct on the point - Thank you!
Thanks! Very clear, easy to follow, learned enough to get me started!
One of the imports used is deprecated. For SQLAlchemy 2.0.10 the import for the declarative_base needs to look like this:
from sqlalchemy.orm import declarative_base
Thanks
Nicely done. Simple and effective example that immediately clarified proper structure.
Great video! I currently create and update SQL rows by calling stored procedures. I want to give SQLAlchemy a try.
Clear and informative video. I have just started to learn orm and sqlalchemy and this video is superb. Thanks for sharing.
stright to the point..awesome man
This has been an awesome tutorial TY, I learned enough to continue my project !
Geatings from colombia !
Thank you very much for the help! :^)
At 14:00 you could also use
results = session.query(Person).filter(Person.lastname == "Smith").all()
with the .all() at the end you select every element fitting to the filter!
Life saver!
really great session , everything is clear and easy to understand. thank you...
This is a treasure!
Thank you so much!
Hey man solid video, but should add a note that you are, in fact, using the legacy (albeit backward compatible) syntax here. Mapped_column() is now the new factory function for the Column() class
this video has saved me a lot of time. thanks for your work :*
1:09 this is exactly what I was looking for. THANK YOU!
Excellent tutorial. Thank you for the content.
Isn‘t the use of Column legacy? I know this video is 8 months old. I think a better way is to use: first_name: Mapped[str] = mapped_column(String, nullable=True)…. If the information are optional one can use Optional from the typing library
This was very well explained.
Another great video. You are such a good teacher, while your style of explaining things seems so effortless.
Thank you for this video, I was looking for soft introduction to sqlalchemy. Their documentation is quite difficult and their quick start actually don’t show the easiest ways to use it
In the last query execution it results out the object of respective classes. In the iteration of the loop, print(r) displayed both classes __repr__ method string format
Thanks. That helped a lot!
Informative thanks!
thanks. fantastic video!
So with this I am now writing data from a PLC to a database to keep records for longer periods of time with out having to hold the data or do the logic inside of the PLC, thanks so much!
hey, i am very curious about your work. i used to work with plcs but only assembly/wiring... i am now studying cs. could u please share your foundations? some key course maybe. thanks in advance. (can be in spanish, gracias)
Bruh, I had no idea you could do this with SQLAlchemy. I use SQL a lot and always hated writing qries on Python
There are other alternatives to sqlalchemy too, like the peewee orm which is very nice as well
great video keep it up!
Thank you man.
Hello, i have the same problem like you, when i add a table the base.metadata.create_all() dosnt create the table, how to solve that ? In a poppulated database is not a option to delete the db, i used alembic but some times dosnt generate the revision file with the changes.
Great Help
Uuuuu... exactly what I was looking for! Thanks!
plenty of these on RUclips already
@@chriskeo392 not on SQL Alchemy. Not in good english,
@@chriskeo392 not in GOOD english, read carefully please.
@@piotrmazgaj I think you need to look up English tutorials instead 🤡
Actually the reason why people call it sequel instead of SQL is because at first it was SEQL Structured English Query Language but then they skiped the E.
Nice and simple
Can we create an engine if are database user only has Create, Drop, Delete permissions, or does our database user need to have All permissions set up?
Your video gives a good introduction to SQLalchemy. I would like to make one comment though. As far as I know best practice for table creation is to use singular nouns and not pural names. It would be also easier if the object name and the table name is the same. So in your example it would have been better e.g. to use for class Person __tablename__ = "person".
what if I have 5000 entries to insert? Is there any batch way, like a loop to read data from csv and add to the SQL DB or any other less manual way?
I am thinking of making a similar module for my own project.
Thank you bro
Question: At around 7:00 the variable "firstname" defined inside the class is also defined as a variable in the constructor __init__ method. Usually, a class attribute can be called with self. ... , so is the init method overwriting the column definition or is the self.firstname call non-unique?
In python there is a distinction between and instance attribute and class attribute. The class attribute is in the class’s __dict__ while the instance attr is in the instance’s __dict__. Sql alchemy’s major flaw is that it relies on this approach instead of a more pythonic one
At 13:55, you can add .all() at the end to return a list of the results, instead of iterating over them and printing:
results = session.query(Person).filter(Person.lastname == "Blue").all()
How do you configure pycharm and sqlserver to follow this tutotrial?
Quick Question: How can we have multiple databases made and used? reason for asking is to create the microservice architecture environment.
This would also be awesome for teaching/learning SQL. You can tell SQLAlchemy what you want to do, and use the output to learn how to do it in SQL.
Thank you.
from sqlalchemy import inspect
inspector = inspect(engine)
if not inspector.has_table('DB'):
Base.metadata.create_all(engine)
Nice video! The model constructors are generated automatically by sqlalchemy.
Maybe you should use Jupyter notebook to avoid deleting the database every time running the code.
this alchemy is the dope for us olderfarts trying to createwhile learning something to use -and hopefully rebuild some monstrosity i built in excel way back ..lol..
+
Is it possible to use sqlalchemy for more advanced sql queries? For example, I mean joining, subqueries or CVEs. Also how to do queries on views?
Yes, you can use SQLAlchemy to perform advanced queries, and you can further customize the Python models, relationships, etc. If you find that the syntax of a query gets challenging in SQLAlchemy (has happened to me a few times), it also provides methods for you to be able to write the raw SQL yourself, and have the engine execute the query. I generally just wrote raw SQL when having to query views, though I admit most of my usecases did not need views, so I never dove too far with them.
In this, you are creating your Engine in one file
What am I to do if I have Classes in separate files?
I assume I'm not to make multiple Engines for each Class and I'm not entirely sure how I make one engine for everything outside of the scope of the single file.
I intend to use the async variation of this and multiple users will be potentially calling things.
Create the engine and session, create functions returning pointers to each (eg, GetEngine()) , save as "db . py". In another file:
import db
import db
engine = db.GetEngine()
session = db.GetSession()
UserWarning: pandas only supports SQLAlchemy connectable (engine/connection) or database string URI or sqlite3 DBAPI2 connection. Other DBAPI2 objects are not tested. Please consider using SQLAlchemy.
MD_agric_df = pd.read_sql_query(text(sql_query), connection) i got this error guys hope someone help ASAP in my jupyter notebook please
Which plugin did you use to directly view .db file in Pycharm?
It is a feature of PyCharm. If it does not work for you, maybe it is only available in the Professional edition.
can you use it with routes
If anybody is getting a warning saying:
"Deprecated API features detected! These feature(s) are not compatible with SQLAlchemy 2.0."
you can fix it by changing "from sqlalchemy.ext.declarative import declarative_base" to "from sqlalchemy.orm import declarative_base"
good stuff
Nice!
Hello, is there any better way to create a table with hundreds of columns, instead of writing them by hands as arguments in the class? Thanks
Regards
Where do you have the data containing hundreds of columns currently?
Well what happens if I want to access a database which already exists
Could you share the code you write in the tutorial?
Perfect
Brilliant video Thank You Sir :)
Can I do the same with an auto increment column ?
Thanks
I think you just have to add autoincrement attribute when specifying the id column:
eg:
id = Column(Integer, primary_key=True, autoincrement=True)
I work with pycharm for my classes, but never tried to create a database in pycharm. is that something that I have to add to pycharm? I have to use to PgAdmin everysingle time and use postgres
figured it out finally!
re-writing __init__ function is useless if you don't implement custom behaviors within it and is only prone to raise errors
sorry but how did you open the database in pycharm ?
This is a really helpful video! Do you use some sort of a plugin to view the database inside PyCharm? :)
On vs code i use sqlite viewer to view the database
Need SQLModel tutorial becz itz hard to find... the one already exist doesn't help me at all ...
Can I use the dataclasses to simplify the class definition ?
Yes You can do it
thx
could you do a odoo tutorial?
What is the use of the representation function i did not understand. Can anyone explain?
When You print a object in python it prints in the screen the result of rep method, You can Overdrive this method inside your class to print what You want.
"Persons" is indeed a valid English word, and would be the more appropriate choice for the database.
great
Can it be used for video game development in Python?
Yes, of course. You can use this for an easier way to read and write persistent data. Fast-changing data, such as the position of an opponent, is stored in RAM, while slower-changing and longer-term data, such as a high score table, is stored in a database. To work with the database, you can use SQAlchemy
@@ptichiy-krik
And that's what I am interested in.
Thank you for your explanation.
Can you do a vid on how to build a neural network to extract data from a lisence
You can use object character recognition (ocr) i don't remember what's the name of the package in python
I prefer querys it is faster for large and complex databases
Is sqlalchemy usable with @dataclass?
Yes, You can use it
SQL - Squeel
"persons" is valid English, just a bit unusual
Thx_.
Can you say squeal?
persons is english by the way
Did you just assume Anna Blue's gender
First