sqlalchemy

问题 I'm noticing some odd behavior in the SQL generated for queries against string fields in MS SQL. Server version: SQL Server 2014 12.0.5000.0 Collation: SQL_Latin1_General_CP1_CI_AS Python version: 3.7 Our database has a mix of NVARCHAR (mostly newer) and VARCHAR (mostly older) fields. We are using SQLAlchemy to connect our Python application to the database, and even though we specify that a column is of type String (as opposed to Unicode ), the executed SQL always comes out in NVARCHAR

问题 I am using sqlalchemy and pandas to load dataframe to Oracle database. Since 'multi'method allows to upload in bulk, I choose that method. My pandas version is 1.0.1. However I got the error as following: The 'oracle' dialect with current database version settings does not support in-place multirow inserts. from sqlalchemy import create_engine oracle_connection_string = ( 'oracle+cx_oracle://{username}:{password}@' + cx_Oracle.makedsn('{hostname}', '{port}', service_name='{service_name}'))

问题 At some point in the past I've run an alembic migration which creates a users table like... def upgrade(): ... op.create_table( "users", sa.Column("id", sa.Integer(), autoincrement=True, nullable=False), ... sa.Column("type", sa.Enum("Foo", "Bar", "Baz", name="usertype"), nullable=False), ... ) ... ...which automatically creates the enum named usertype with the values "Foo", "Bar", "Baz" . Now, I want to make some other table which also references that same enum. e.g., def upgrade(): ... op

问题 is it possible to somehow use function register_composite from psycopg2, when i am using sqlalchemy to connect to postgresql database? My problem is that I want SQLAlchemy to handle custom composite type that i created in postgresql like this: CREATE TYPE card AS (value int, suit text); Sqlalchemy returns me values of this type as an string and I would like to somhow learn sqlalchemy my new type. If found some information about creating custom composite types in SQL alchemy ORM, but I am

问题 I have the following simple setup, where fromDate and toDate are strings on the format "YYYY-MM-DD": class SomeType(Base): date = Column(DateTime) def findAll(fromDate, toDate): return session.query(SomeType).filter(SomeType.date >= fromDate, SomeType.date <= toDate).all() The problem is that it doesn't find what I want it to find unless I modify the input dates like this: def findAll(fromDate, toDate): fromDate = fromDate + " 00:00" toDate = toDate + " 24:00" return session.query(SomeType)

问题 I'm working with Flask-SQLAlchemy in PyCharm. When I try to create instances of my User model by passing keyword arguments to the model, PyCharm highlights the arguments with an "Unexpected argument(s)" warning. When I create instances of other models, I don't get this warning. Why am I getting this error for my User model? class User(db.Model, UserMixin): id = db.Column(db.Integer, primary_key=True) username = db.Column(db.String, unique=True, nullable=False) new_user = User(username="test")

问题 I'm working with Flask-SQLAlchemy in PyCharm. When I try to create instances of my User model by passing keyword arguments to the model, PyCharm highlights the arguments with an "Unexpected argument(s)" warning. When I create instances of other models, I don't get this warning. Why am I getting this error for my User model? class User(db.Model, UserMixin): id = db.Column(db.Integer, primary_key=True) username = db.Column(db.String, unique=True, nullable=False) new_user = User(username="test")

问题 So I want to execute a filter on all Columns of my Database Model which uses table inheritance. I am by no means sure if this is actually do-able or not. To get started let's use the same inheritance example from the SQLAlchemy Doc just slightly modified. I've omitted the imports here. class Employee(Base): __tablename__ = 'employee' id = Column(Integer, primary_key=True) name = Column(String(50)) type = Column(String(50)) __mapper_args__ = { 'polymorphic_identity':'employee', 'polymorphic_on

问题 I am using MySQL (running InnoDB), and wrapped the entire thing using sqlalchemy. Now, I would like to generate changes in my database by using (see docs) sqlalchemy_utils.functions.create_database(...) Generally the above function does what it is supposed to. The only exception being the generation of unique indexes. Say, I define a table like this: ## ... # DeclBase = declarative_base() ## ... class MyTable(DeclBase): __tablename__ = 'my_table' id = Column(Integer, primary_key=True) attr_1

问题 With a float value representing date and time with millisecond precision: import datetime float_time = 1485538757.29289 print datetime.datetime.fromtimestamp(float_time) prints: 2017-01-27 09:39:17.292890 To store it in db: from sqlalchemy import Column, DateTime from sqlalchemy.ext.declarative import declarative_base Base = declarative_base() class MyTable(Base): __tablename__ = 'mytable' time_created = Column(DateTime, nullable=False) But saved value is rounded down to 2017-01-27 09:39:17