migration

问题 I'm trying to deploy a rails app to Heroku and I'm running into some basic git problems. I'm new to this all -- rails, git, heroku -- so I'm afraid I'm getting lost on what's probably a fairly basic concept. I've pushed the app to Heroku, but when I'm migrating the db ($ heroku rake db:migrate), I keep getting the following error: rake aborted! Multiple migrations have the name CreateFavorites Checking my github repository, and sure enough, there are two migrations: 20101007030431_create

问题 I'm trying to deploy a rails app to Heroku and I'm running into some basic git problems. I'm new to this all -- rails, git, heroku -- so I'm afraid I'm getting lost on what's probably a fairly basic concept. I've pushed the app to Heroku, but when I'm migrating the db ($ heroku rake db:migrate), I keep getting the following error: rake aborted! Multiple migrations have the name CreateFavorites Checking my github repository, and sure enough, there are two migrations: 20101007030431_create

问题 After migration to AndroidX i have the following exception at startup: LoadedApk: Unable to instantiate appComponentFactory java.lang.ClassNotFoundException: Didn't find class "androidx.core.app.CoreComponentFactory" on path: DexPathList[[],nativeLibraryDirectories=[/data/app/com.apps.entertainmentsolutions.offhole-yUKw5A4ysDVrPyO-DpnhKg==/lib/arm64, /system/lib64, /system/vendor/lib64]] at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:134) at java.lang.ClassLoader

问题 I have to migrate a class from opensaml 2.6 to opensaml 3.1.1 Compiling I obtain some errors 1) Element plaintextElement = getElementAssertion(inputBean); String xml = XMLHelper.prettyPrintXML(plaintextElement); I can't find the class XMLHelper in the new version. 2) DefaultBootstrap.bootstrap(); builderFactory = Configuration.getBuilderFactory(); Configuration.getMarshallerFactory().getMarshaller(assertion).marshall(assertion); I can'f find class DefaultBootstrap and I can't find a class

问题 There are several questions on SO about version control for SQL and lots of resources on the web, but I can't find something that quite covers what I'm trying to do. First off, I'm talking about a methodology here. I'm familiar with the various source control applications out there and I'm familiar with tools like Red Gate's SQL Compare, etc. and I know how to write an application to check things in and out of my source control system automatically. If there is a tool which would be

问题 I am trying to follow the Django tutorial and I faced the following error when I enter python manage.py makemigrations polls Unknown command: 'makemigrations' Here's the link to the tutorial and I accomplished all the previous steps successfully and I am not sure what's going wrong now or how to fix it. P.S.: I have already included "polls" in the INSTALLED_APPS! INSTALLED_APPS = ( 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django

问题 I am trying to follow the Django tutorial and I faced the following error when I enter python manage.py makemigrations polls Unknown command: 'makemigrations' Here's the link to the tutorial and I accomplished all the previous steps successfully and I am not sure what's going wrong now or how to fix it. P.S.: I have already included "polls" in the INSTALLED_APPS! INSTALLED_APPS = ( 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django

问题 I had originally created a table with column as t.string "email", :default => "", :null => false The requirement has changed and now I need to allow email to be null. How can I write a migration to make :null => true 回答1: Try: change_column :table_name, :email, :string, :null => true 回答2: I could not get the above solution to work with Active Record 4.0.8 and Postgresql 9.3 However change_column_null worked perfectly. change_column_null :users, :email, true The reverse has a nice option to

问题 I am working on migrating data from WL 5.0.6.2 to 6.2. While doing that I encountered problems running data migration tool. Background: Approach: we export the WRKLGHT table from 5062 DB to an intermediate DB for data migration so the running DB is not affected. DBs: 1. schema: proj its storing 5062 runtime data, upgrade-worklight-506-60-oracle.sql, upgrade-worklight-60-61-oracle.sql upgrade sql are executed. 2. schema: proj6 its blank DB at first, "create-worklightadmin-oracle.sql" is

问题 I have such models: student: class Student < ActiveRecord::Base has_many :participations, dependent: :destroy has_many :subject_item_notes, dependent: :destroy has_many :payments, dependent: :destroy has_many :subject_items, dependent: :destroy, through: :participations has_many :subject_items, dependent: :destroy validates :first_name, :last_name, presence: true accepts_nested_attributes_for :subject_items end and subject_item: class SubjectItem < ActiveRecord::Base has_many :participations,