How to Programming with Flask-sqlalchemy

testing,flask,mocking,flask-sqlalchemy

You cannot sqlalchemy to be able to handle cases like this out-of-the-box. The code below is what I would use in such case: class Player(db.Model): id = db.Column(db.Integer, primary_key=True) name = db.Column(db.String(64), index=True, unique=True) email = db.Column(db.String(120), index=True, unique=True) avatar = db.Column(db.String(120)) skill = db.Column(db.Integer) class Participant(db.Model): player_id = db.Column(db.Integer,...

Problems trying to mock a Model within Flask-SQLAlchemy

So, I found a solution after banging my head on the keyboard for a few hours. The problem seems to be the following (if anyone knows better, please correct me). When I run mock.create_autospec(User), the mock module tries to inspect all attributes of User to create the adequate spec for...

Default scope for queries using Python + Flask-SqlAlchemy

One of many ways is to add class method. With python Class definition, you are free to add your own methods, by the way. class Resource(db.Model): # .... your existing code @staticmethod def customq(limit, offset): """This method returns an instance of flask_sqlalchemy.BaseQuery""" return Resource.query.filter_by(is_active=1).limit(limit).offset(offset) Then your example code becomes: @app.route('/resources',...

SQLAlchemy - Filter query, exclude parent where one of many children meet criteria

json,flask,one-to-many,flask-sqlalchemy

Query below should do it: q = (session.query(Parent) .filter(Parent.children.any(Child.value.ilike('%{}%'.format(value1)))) .filter(Parent.children.any(Child.value.ilike('%{}%'.format(value2)))) .filter(~Parent.children.any( db.or_(Child.value.ilike('%{}%'.format(value3)), Child.value.ilike('%{}%'.format(value4)), ) )) ) Few points: you need an or for Condition-3 you also should use NOT has any children... (which is done using ~) instead or the not which you have inside. Filter for Condition-3 should be:...

Linking tables in SQLAclhemy foreign_keys error [Flask]

So with the help of @dirn I got it to work by acessing the backref posts that I have made in the Post class under the category which was backref=db.backref('posts', lazy='dynamic')) In my route category/<name>/posts/ which is kind of which will look like @api.route('/category/<int:id>/posts/') def get_category_posts(id): category = Category.query.get_or_404(id) page...

Flask/SQLalchemy/Jinja2 — nested loop rendering

python,flask,jinja2,flask-sqlalchemy

Your loop didn't quite make sense as it was not an dictionary. Since you have answers in the questions, you can just grab the questions, and automically grab the answers at runtime as it is lazy loaded when you iterate through q.answers in your template. routes.py @app.route('/quiz') def quiz(): questions...

Switching from SQLite to MySQL with Flask SQLAlchemy

python,mysql,database,sqlite,flask-sqlalchemy

The tutorial pointed by you shows the right way of connecting to MySQL using SQLAlchemy. Below is your code with very little changes: My assumptions are your MySQL server is running on the same machine where Flask is running and the database name is db_name. In case your server is...

Make only one BestFriend with flask-sqlalchemy

python,database,flask,sqlalchemy,flask-sqlalchemy

To change from a many-to-many relationship to a one-to-one, start by removing the best_friends table. friends = db.Table('friends', db.Column('user_id', db.Integer, db.ForeignKey('user.id')), db.Column('friend_id', db.Integer, db.ForeignKey('user.id')) ) You then want to add a foreign key to User that references another User. class User(db.Model): id = db.Column(db.Integer, primary_key = True) name = db.Column(db.String(50),...

Get inserted key before commit session

python,database,sqlalchemy,relationship,flask-sqlalchemy

You could use flush() to flush changes to the database and thus have your primary-key field updated: parent = Parent() db.session.add(parent) db.session.flush() print parent.id # after flush(), parent object would be automatically # assigned with a unique primary key to its id field child = Child() child.parent_id = parent.id db.session.add(child)...

Relationship between two tables one with 2 foreign keys in flask-sqlalchemy

Below should work: class Messages(db.Model): MessageId = db.Column(db.INTEGER, primary_key=True, autoincrement=True) SenderId = db.Column(db.INTEGER, db.ForeignKey('users.UserId'), nullable=False) ReceiverId = db.Column(db.INTEGER, db.ForeignKey('users.UserId'), nullable=False) Message = db.Column(db.String, nullable=False) # define relationships sender = db.relationship(Users, foreign_keys=[SenderId], backref='sent') receiver = db.relationship(Users, foreign_keys=[ReceiverId], backref='received') Usage example: u0 =...

scoped_session object has no attribute 'create_all'

It's connection.create_all(), you added session in the middle. Unrelated to the immediate problem, there are other things that don't look right. You don't need to commit after running create_all. The extension instance is usually named db. The DB class does nothing, just write your create_all function on its own. You...

What is the relationship() function used for in SQLAlchemy

python,flask,sqlalchemy,flask-sqlalchemy,sqlalchemy-migrate

relationship does not affect the database schema. It provides a convenient way to access related objects. In this instance it allows you to all Child objects that are related to a Parent through the children attribute. backref then adds a parent attribute to all Child objects. By default, related objects...

Python/SQLAlchemy migration - ValueError: need more than 3 values to unpack when migrating

Yes, td.columns_different is a dict of columns that changed between previous and current revision. This code belongs to sqlalchemy-migrate package. Comment from the source[1]: class TableDiff(object): """ ... ..attribute:: columns_different A dictionary containing information about columns that were found to be different. It maps column names to a :class:`ColDiff` objects...

Associate "external' class model with flask sqlalchemy

python,flask,sqlalchemy,flask-sqlalchemy,flask-security

I spent a lot of time looking for an answer to this. My conclusion is that it is not at this time possible to integrate what I'm going to call an "abstract" sqlalchemy model into flask-sqlalchemy or flask-security. It was a huge time sink trying to integrate them. I strongly...

Flask-SQLAlchemy close connection

postgresql,flask,sqlalchemy,flask-sqlalchemy

SQLAlchemy sets up a pool of connections that will remain opened for performance reasons. The PostgreSQL has a max_connections config option. If you are exceeding that value, you need to either lower your pool count or raise the max connection count. Given that the default max is 100, and you've...

Adding columns from joined table

python,flask-sqlalchemy,data-migration,alembic,flask-migrate

I found the solution. The correct way of querying should be: models.Detail.query.join(details_usages).add_columns(details_usages.c.is_required).all() ...

Get “insert_id” for one to one relationship in Flask, SqlAlchemy

flask,flask-sqlalchemy

I couldn't find an exact solution. If anyone is wondering, I ended up working around it by executing SQL directly. It's not ideal, but it gets the job done for now. I ended up inserting on row at a time, here's the code below: @app.route('/_add_funding') def add_funding(): funding_type = request.args.get('funding_stage',...

change database migrations from sqlalchemy-migrate to Flask-Migrate

There are three possible ways to handle this, two are relatively easy, but the last is pretty laborious: 1. Only track future migrations with Flask-Migrate This is the easiest, but less interesting. Just install and setup Flask-Migrate as you would for a new project, and the next time you need...

SQLAlchemy: Specifying session to use for model

flask,sqlalchemy,flask-sqlalchemy

SQLAlchemy sessions provide a no_autoflush context manager. This will suspend any flushes until after you exit the block. model1 = Model(name='spam') db.session.add(model1) # This will flush with db.session.no_autoflush: model2 = Model() db.session.add(model2) # This will not model2.name = 'eggs' db.session.commit() ...

Getting user by primary key in flask

python,flask,jinja2,flask-sqlalchemy

I noticed two things in your code: # this <a href={{url_for('profile')}}> # should be <a href={{url_for('profile', id=contact.id)}}> # otherwise Flask can't find the route, because it needs an id And the other one: {% for detail in Contacts %} There is no such thing as a Contacts variable in your...

Database created empty when models are in a separate file?

python,flask,flask-sqlalchemy,flask-admin

Since defining your model directly in __init__.py works, it follows that you need to import your model(s) into __init__.py. You can add an import in __init__.py after you create an SQLAlchemy object: db = SQLAlchemy() from .models import User This works, but it feels horribly wrong and dirty to me....

Tyring to set up modelview with Flask-Admin causes ImportError

Your code has the line from app.models import User in __init__.py. The problem is that app.models has from . import db. This is a circular import: __init__ tries to import User, which tries to import db, which isn't defined until after __init__ tries to import User. To solve this, move...

Flask-SQLAlchemy filter_by and follow multiple backrefs

virtualenv,flask-sqlalchemy

You have to join the Post and Category first, and i made some small corrections on your tests: db.create_all() e = Editor('Dude') py = Category('Python', e) p = Post('Hello Python!', 'Python is pretty cool', py) db.session.add(py) db.session.add(p) db.session.add(e) print Post.query.filter_by(category=py).all() print Category.query.filter_by(editor=e).all() print Post.query.join(Category).filter_by(editor=e).all() ...

SLQAlchemy, Flask: AttributeError: 'module' object has no attribute 'create_all' [closed]

If you’re trying to use the create_all on db, that’d be it. modelx.db.create_all()...

TypeError: key is not a string

python,flask,flask-sqlalchemy,flask-restful

Your problem is in this line: return {id:marshal(question, questionlist_fields)} I think you wanted this: return {'id': marshal(question, questionlist_fields)} In some languages, notably JavaScript, all dict keys are strings, and the syntax allows you to leave the quotes off. In Python, dict keys can be anything you want.* If you want...

change Test database From sqlite to Postgresql

python,postgresql,flask,flask-sqlalchemy,flask-testing

As the error says, there is no database called "mytest" on the PostgreSQL server you're pointing to. Unlike SQLite which will create a file for the database if it doesn't exist, with PostgreSQL you need to create the database on the server before using it. Assuming PostgreSQL is otherwise set...

Select attributes from different joined tables with Flask and SQLAlchemy

python,orm,flask,sqlalchemy,flask-sqlalchemy

q = db.session.query(Phrase.content, Meaning.content).join(Meaning).all() ...

Getting errors with passing parameters with fliter_by function in SQLAlchemy

python,python-2.7,flask,sqlalchemy,flask-sqlalchemy

Use filter, not filter_by. filter_by is a shortcut to filter that applies the equality op to keyword args, you can't use it for other ops. filter takes operations, such as User.name == 'davidism' or STDcodes.city.startswith(line), and applies them to the query. filter_by is a shortcut that takes keyword arguments instead...

Can a Field act as both Foreign and Primary Keys in the same table?

database,foreign-keys,relational-database,primary-key,flask-sqlalchemy

In short - yes. Having the same field as a primary key and a foreign key is used to create a 1:0..1 relationship. A user may have a single record of details, but cannot have multiple records of details, and you cannot have details for users that do not exist...

How can I add a foreign key constraint on an existing table column via SQLAlchemy?

python,flask,sqlalchemy,flask-sqlalchemy,alembic

The Alembic op you are looking for is create_foreign_key. op.create_foreign_key( 'fk_location_message_campaign', 'location_messages', 'campaigns', ['campaign_id'], ['id'], ) It is recommended that you use automatic constraint naming so that you can pass None as the name rather than naming it manually....

Flask-SQLAlchemy - How to append a value to a column?

python-3.x,flask,sqlalchemy,flask-sqlalchemy

Your models definitions are not what you really want. User.classes_id defines exactly one value. Right answer depends of requirements. What type of relationships must be there? Many User to many Classes (M:M)? In this case you would create models like: user_to_classes = Table('user_to_classes', Base.metadata, Column('class_id', Integer, ForeignKey('class.id')), Column('user_id', Integer, ForeignKey('user.id'))...

Base query to work even if parameters not supplied

flask,flask-sqlalchemy,flask-login

You don't have to built your entire query in one line. You can build it as you go. query = Company.query if size: query = query.filter(Company.size == size) if industry_id: query = query.filter(Company.industry_id == industry_id) result = query.all() If you feel like this is too verbose, you could build a...

AttributeError: 'User' object has no attribute 'is_active'

Your indentation is wrong. Instead of defining methods on User, you've defined module-level functions. class User(db.Model): __tablename__ = "Contacts" id = db.Column(db.Integer, primary_key = True) name = db.Column(db.String(50)) email = db.Column(db.String(50)) age = db.Column(db.Integer) def __init__(self, name, email, age ): self.name = name self.email = email self.age = age def...

Recursively select (with limited depth) relationships in SQLAlchemy using ORM, declarative style, and Association objects

python,postgresql,recursion,sqlalchemy,flask-sqlalchemy

I hope I did not overcomplicate your model, but in order to test the query (which follows below) I used the following model definition: The MODEL: class Room(Base): __tablename__ = 'room' id = Column(Integer, primary_key=True) name = Column(String) exits = association_proxy( 'lnk_exits', 'to_room', # creator=lambda v: Exit(to_room=v), creator=lambda k, v:...

Flask-Sqlalchemy taking non unique values for a 'unique' integer

I suppose you declared email as UNIQUE in the database, but not registration_num. Setting unique=True in the model does not automatically influence the database and SQLAlchemy does not check if there are some rows with that value already. unique=True it is used by create_all or sqlalchemy-migrate.

how to use .query attribute in sqlacodegen models

python,json,flask-sqlalchemy,flask-restful,flask-restless

It sounds like you're used to using Flask-SQLAlchemy, which includes the secret sauce to allow the functionality you mention. The Flask Docs on SQLAlchemy indicate how to get that same functionality: from sqlalchemy import create_engine from sqlalchemy.orm import scoped_session, sessionmaker from sqlalchemy.ext.declarative import declarative_base engine = create_engine('sqlite:////tmp/test.db', convert_unicode=True) db_session =...

Python Flask SQLalchemy JSON POST Error

You are posting to the URL without a / at the end, but you specified your route with a trailing /. When you do that, Flask issues a redirect to the 'canonical' URL, with the /. Because you are using POST, the post data will be lost, so in debug...

flask-sqlalchemy, sql count records in a relationship and then join to a users table

python,postgresql,flask-sqlalchemy

select users.*, count(*) over (partition by friendship.user) from users inner join friendship on users.id = friendship.user order by count ...

SQLAlchemy relationships, when to use which relationship?

python,sqlite,flask,sqlalchemy,flask-sqlalchemy

Having db.relationship is very helpful in some cases and can help you to avoid long queries. For example Without db.relationship: role = ... # some role Session.query(User).filter_by(role_id=role.role_id).all() Versus with db.relationship: role = ... # some role role.users Concerning relationship options, most useful for you is probably backref. It creates back...

One to many SQL relationship

python-2.7,flask,flask-sqlalchemy

Flask-SQLAlchemy's documentation covers creating a one-to-many relationship. It provides an example of one Person having many Addresses. class Person(db.Model): id = db.Column(db.Integer, primary_key=True) name = db.Column(db.String(50)) addresses = db.relationship('Address', backref='person', lazy='dynamic') class Address(db.Model): id = db.Column(db.Integer, primary_key=True) email = db.Column(db.String(50)) person_id = db.Column(db.Integer, db.ForeignKey('person.id')) This matches what you have. The...

SQLAlchemy sum of a column btw 2 dates

sqlalchemy,flask-sqlalchemy

start_date, end_date = date(2014, 2, 1), date(2014, 3, 31) q = (db.session.query( db.func.sum(Income.amount).label("total_amount"),) # @note: any of the three below should do the job: .filter(Income.date >= start_date).filter(Income.date <= end_date) # .filter(Income.date.between(start_date, end_date)) # .filter(between(Income.date, start_date, end_date)) # first do: from sqlalchemy.sql.expression import between ) ...

Error importing models when trying to run app [duplicate]

python,google-app-engine,flask,sqlalchemy,flask-sqlalchemy

Looks like you are in a circular import, as @jwalker commented. Three comments here: You can check blueprints to avoid circular imports in Flask. If the idea is to keep it simple, declare your models within app.py (it is not the ideal, but for initial learning purposes it makes the...

Cannot access db when running code from Interactive Console

You need to be in an app context (or a request context) to access application bound objects. An easy way to achieve this is to use Flask-Script, which provides a shell command that sets up the application for you. Or use Flask's integration with Click if you are using the...

How to create a user 'programmatically' with Flask-user extension?

python,postgresql,sqlalchemy,flask-sqlalchemy

That's how it basically works: user = User() user.username = request.json['username'] user.first_name = request.json['first_name'] user.last_name = request.json['last_name'] user.email = request.json['email'] user.password = user_manager.hash_password(request.json['password']) db.session.add(user) db.session.commit() ...

Copying oldtable to newtable with slight differences in newtable?

Something like this should be what you're looking for: oldTypeOnes = session.query(oldTable).filter(oldTable.type == 1).all() for oldTypeOne in oldTypeOnes: session.add(newTable(parent_id=oldTypeOne.id, type=oldTypeOne.type, \ name=oldTypeOne.name)) session.commit() ...

Isolating py.test DB sessions in Flask-SQLAlchemy

python,unit-testing,flask,flask-sqlalchemy,py.test

1. According to Session Basics - SQLAlchemy documentation: commit() is used to commit the current transaction. It always issues flush() beforehand to flush any remaining state to the database; this is independent of the “autoflush” setting. .... So transaction.rollback() in session fixture function does not take effect, because the transaction...

How to select_related() in Flask/SQLAlchemy?

answers = Question.query.options(joinedload(Question.answers)).get(5).answers The expression Question.query.options(joinedload(Question.answers)).get(5) issues the query with a join and evaluates to a Question instance. Accessing answers attribute does not issue any queries. You could also do it more explicitly answers = Answer.query.filter_by(question_id=5).all() ...

NameError: global name 'User' is not defined

flask,flask-sqlalchemy

You need to import your models into your views module: from models import User ...

Where can I find a list of the Flask SQLAlchemy Column types and options?

python,flask,flask-sqlalchemy,flask-restful

I think you're looking for the Column and Data Types page in the documentation. A little HTML parsing gives: BIGINT BINARY BLOB BOOLEAN BigInteger Boolean CHAR CLOB Concatenable DATE DATETIME DECIMAL Date DateTime Enum FLOAT Float INT INTEGER Integer Interval LargeBinary MatchType NCHAR NVARCHAR Numeric PickleType REAL SMALLINT SchemaType SmallInteger...

flask sqlalchemy update error - update() missing 1 required positional argument: 'self'

You are calling update on the User class rather than an instance of User. You could instantiate the User before calling update: user = User.query.get(id) user.update(email=args.email) Or you could make update a @classmethod and have it take the cls as the first argument rather than self and it would instantiate...

how to store binary file recieved by Flask into postgres

python,flask,flask-sqlalchemy,psycopg2,werkzeug

The objects in request.files are FileStorage objects. They have the same methods as normal file objects in python. So, to get the contents of the file as binary, just do this: data = request.files['file'].read() Then pass that parameter into the INSERT....

How can I programmatically set the 'target_metadata' required by Alembic for use with the command API?

python,sqlalchemy,database-migration,flask-sqlalchemy,alembic

The long answer is that you don't set metadata there, you set it when creating the MigrationContext. Which requires that you create a Config, then a ScriptDirectory, then an EnvironmentContext first. Then you need to use these objects correctly when running revisions to set up the environment yourself. The short...

Openshift app with flask, sqlalchemy and sqlite - problems with database reverting

python-3.x,sqlite3,flask,openshift,flask-sqlalchemy

Via the note at the top of the OpenShift Cartridge Guide: "Cartridges and Persistent Storage: Every time you push, everything in your remote repo directory is recreated. Store long term items (like an sqlite database) in the OpenShift data directory, which will persist between pushes of your repo. The OpenShift...

Best association approach to connect Sensor model to others

sqlalchemy,flask-sqlalchemy

After two days of experiments I have came to final conclusion. Examples have been taken from this source. "Discriminator on association" (candidate for answer): (+) has backward reference (?) can have 1 parent object (-) complexity "Generic Foreign Key": (+) low complexity (+) has backward reference (?) can have 1...

How teardown_request() works with Python- Flask?

flask,flask-sqlalchemy,sqlalchemy-migrate,flask-migrate,geoalchemy2

teardown_request registers a function to be called at the end of each request whether it was successful or an exception was raised. It is a good place to cleanup request scope objects like a database session/transaction. That is all your code sample is doing. It is safe to use that...

How to create a migration script to add a Geometry column in SQLAlchemy-Migrate?

If you are following Miguel Grinberg's tutorial you are using SQLite database. GeoAlchemy2 – if I'm not wrong – supports only PostgreSQL/PostGIS, as @dirn pointed out in the comment. The solution would be to get a PostgreSQL server running. SQLAlchemy deals fine with PostreSQL. Once you got it, just edit your...

How to fix itsdangerous.BadTimeSignature Signature Error

python,cookies,flask,flask-sqlalchemy,flask-login

You are creating a new secret each time here: from itsdangerous import URLSafeTimedSerializer app.secret_key = gen_random_key() login_serializer = URLSafeTimedSerializer(app.secret_key) Don't do that. Create one secret for your application, and keep using this throughout. Your keys are signed with this server-side secret and then when the cookie is sent back from...

Flask-SQLAlchemy not creating my tables

on changing from __init__ import db to from modules import db in models.py it worked. when running flask application from outside package one needs to import everything from the package itself and not the individual modules....

Arguments of Column in SqlAlchemy Flask

nginx,flask,flask-sqlalchemy,gunicorn

From SQLAlchemy documentation: sqlalchemy.schema.Column(name, type, *args, **kwargs) Where nameis a str and type is an instance subclassing TypeEngine. More information about **kwargs in the documentation....

SQLAlchemy extension isn't registered when running app with Gunicorn

Only when you start your app with python sever.py is the if __name__ == '__main__': block hit, where you're registering your database with your app. You'll need to move that line, db.init_app(app), outside that block....

backref lazy='dynamic' - does not support object population - eager loading cannot be applied

flask,sqlalchemy,flask-sqlalchemy

The error message tells you exactly what is "wrong": a lazy='dynamic' relationship can't be eager loaded. Dynamic relationships produce new queries, not collections (lists). It doesn't make sense to pre-load a dynamic relationship because the entire point of a dynamic relationship is to be able to construct other queries. Use...

Flask-SQLAlchemy using global DB instance

python,mysql,sqlalchemy,flask-sqlalchemy

Your filter user_groups_n_hosts.end_time < str(date_now) compares a date with a string. Also, you should consider the session as a per-request thing, not a persistent entity across your app. With this in mind, try changing @sched.cron_schedule(second='*/5') def some_decorated_task(): date_now = datetime.datetime.now().date() for item in DBsession.query(user_groups_n_hosts).filter(user_groups_n_hosts.end_time < str(date_now)): print item.id, item.server_users.native_linux_user to...

Speed up updating items individually

SQLAlchemy caches all the queried items internally, but expires that cache when a commit is issued. So the instance accessed in the next iteration is in the "expired" state and SQLAlchemy re-queries the database. So you're effectively doing: a massive query at the beginning for 12000 items 12000 commits 11999...

Flask-Babel do not translate anything in a web project

python,flask,flask-sqlalchemy,flask-login,babel

because the actual locale name parsed by babel is "zh_Hans_CN", name your translation directory to be "zh_Hans_CN", and it will be found.

Flask/SQLAlchemy - Difference between association model and association table for many-to-many relationship?

flask,sqlalchemy,many-to-many,flask-sqlalchemy,model-associations

My apologies, I finally stumbled across the answer in the SQLAlchemy docs... http://docs.sqlalchemy.org/en/rel_1_0/orm/basic_relationships.html#many-to-many ...where they explicitly define the difference: Many to Many adds an association table between two classes. association_table = Table('association', Base.metadata, Column('left_id', Integer, ForeignKey('left.id')), Column('right_id', Integer, ForeignKey('right.id')) ) The association object pattern is a variant on many-to-many: it’s...

Why do I get a 'NameError' with this import?

python,flask,sqlalchemy,flask-sqlalchemy,python-import

db.SQLAlchemy(app) is not defining db, and is only attempting to run a SQLAlchemy() method on db. db = SQLAlchemy(app) however, would define db.

Join two tables and show all combinations

python,flask,sqlalchemy,jinja2,flask-sqlalchemy

You have a relationship between Company and Contact defined, so you already have the contacts grouped by company. It would be more efficient in this case to not specify lazy='dynamic', and your backref should probably be named company. contacts = db.relationship('Contact', backref='company') You can query with a joinedload option to...

Flask and sqlalchemy: Get uploaded file using path stored on database

python,flask,flask-sqlalchemy,flask-wtforms

Well, It's strange but I will answer my own question. The solution is simple, I chose to store only the file names inside the database. Then I created a route to a view that will return the file using the send_from_directory function from flask.ext.uploads @app.route('/boxart/<filename>') def uploaded_boxart(filename): return send_from_directory(app.config['UPLOAD_FOLDER'],filename) So,...

'NoneType' object has no attribute 'owner' when trying to access relationship

.first() returns None if there were no results. So your query for clicked_toy returned no results. You can use get rather than filter when all you're doing is filtering on the primary key. Flask-SQLAlchemy goes one step further by allowing you to raise 404 if there is no result. clicked_toy...

Two ways of creating a flask-SQLAlchemy BaseQuery object - only one works, why?

python,flask,jinja2,flask-sqlalchemy,jinja

You should be able to use db.session.query(Design).all() session.query is how you would perform queries when using SQLAlchemy without Flask-SQLAlchemy. UPDATE To perform a join using Flask-SQLAlchemy's BaseQuery: Design.query.join(YourOtherModel).all() ...

Does db.create_all() check if the database exists?

flask,flask-sqlalchemy

The method only creates tables; so it is up to you to make sure the database is already created. The database has to exist and if the table already exists, you'll receive an error from the database. It will not overwrite or delete tables....

display friends name by Flask Many-to-many sqlalchemy

The name you've chosen, is_friend, is probably causing some of your confusion. Something like friends is a bit clearer. You also don't need the back reference as each User already has the relationship. class User(db.Model): id = db.Column(db.Integer, primary_key = True) name = db.Column(db.String(50), index=True, unique= True) email = db.Column(db.String(50),index=True,...

Python sqlalchemy how to deal with null

python,flask-sqlalchemy,flask-wtforms

SQLAlchemy's driver is mistaking :null as a named bind parameter instead of a value. Simply add a space after the colon to make it clear that null is a value: sql = """update dh_base_measure_get_10 set json='{"username": "test", "measureid": null}' """ ...

SQLAlchemy: How to use order_by based on a calculated value?

python,database,flask,flask-sqlalchemy,app-engine-ndb

Even with SqlAlchemy, you have to think in sets of objects and their values. The query you want involves three different sets: Users, their correct answers and their total answers. Want you want is a query like that (warning, that's just a sample, you could write it much better) select...

How can I use ndb outside of appengine?

Currently this can work using the Remote API. Note that the process for setting up Remote API is a little complicated and using it has some limitations. This article walks through the steps about how to set it up for db, however the process is the same for ndb....

Flask-admin separate view for models filtered by foreign key

python,flask,sqlalchemy,flask-sqlalchemy,flask-admin

The easiest way to solve this problem that I found was to add a link for each quiz to a page with replies where the filter for the field quiz_id is applied. class Replies_view(ModelView): named_filter_urls = True column_filters = ("quiz_id",) class Quiz_view(ModelView): def _question_formatter(view, context, model, name): return Markup( "<a...

flask wtforms_alchemy object has no attribute

flask,flask-sqlalchemy,flask-wtforms,flask-login,flask-restful

UserCreateForm will inherit its fields from the columns you define on User. User has no column named password, therefore UserCreateForm doesn't have such a field. You'll have to add the field yourself. from wtforms.fields import PasswordField class UserCreateForm(ModelForm): class Meta: model = User password = PasswordField() The WTForms-Alchemy docs talk...

How to enforce constraints in `flask-admin`?

python,flask,flask-sqlalchemy,flask-admin

You can implement the on_model_change and on_model_delete functions. So you can check if the data is unique and give a more user friendly message in case a constraint is not satisfied. Here is an example of checking some constraints before the delete/insert/update operation class ExampleView(ModelView): def on_model_delete(self, model): #check constraint...

Performing tasks before insert, remove, etc. in flask-sqlalchemy

python,flask,sqlalchemy,flask-sqlalchemy,nested-sets

I ended up implementing nested intervals (instead of nested sets). I hope it's helpful to folks! class Employee(db.Model): id = db.Column(db.Integer, primary_key=True) employee_name = db.Column(db.String(120)) parent = db.Column(db.Integer, db.ForeignKey('employee.id'), index=True) # implements nested intervals with fractions created = db.Column(db.DateTime, index=True) left_num = db.Column(db.Integer, nullable=False) left_den = db.Column(db.Integer, nullable=False) right_num =...

Flask-SQLAlchemy “MySQL server has gone away” when using HAproxy

python,mysql,flask,flask-sqlalchemy,haproxy

Just to tidy up this question with an answer I'll post what I (think I) did to solve the issues. Problem 1: HAproxy Either increase the HAproxy client timeout value (globally, or in the frontend definition) to a value longer than what MySQL is set to reset on (see this...

Flask with SQLAlchemy tables doesn't link