cheat sheets.

Cheat Sheet Title: [ no_spaces_alphanumeric_only ]

Cheat Sheet:
Methods: create_table(name, options) drop_table(name) rename_table(old_name, new_name) add_column(table_name, column_name, type, options) rename_column(table_name, column_name, new_column_name) change_column(table_name, column_name, type, options) remove_column(table_name, column_name) add_index(table_name, column_name, index_type) remove_index(table_name, column_name) change_table(table_name) {|Table.new(table_name, self)| ...} Available Column Types (mappings are below): * integer * float * datetime * date * timestamp * time * text * string * binary * boolean * decimal :precision, :scale Valid Column Options: * limit * null (i.e. ":null => false" implies NOT NULL) * default (to specify default values) * :decimal, :precision => 8, :scale => 3 Rake Tasks: rake db:schema:dump: run after you create a model to capture the schema.rb rake db:schema:import: import the schema file into the current database (on error, check if your schema.rb has ":force => true" on the create table statements ./script/generate migration MigrationName: generate a new migration with a new 'highest' version (run './script/generate migration' for this info at your fingertips) rake db:migrate: migrate your current database to the most recent version rake db:migrate VERSION=5: migrate your current database to a specific version (in this case, version 5) rake db:rollback: migrate down one migration rake db:rollback STEP=3: migrate down three migrations rake db:migrate RAILS_ENV=production: migrate your production database SQL: Queries can be executed directly: execute 'ALTER TABLE researchers ADD CONSTRAINT fk_researchers_departments FOREIGN KEY ( department_id ) REFERENCES departments( id )' Example Migration: class UpdateUsersAndCreateProducts < ActiveRecord::Migration def self.up rename_column "users", "password", "hashed_password" remove_column "users", "email" User.reset_column_information User.find(:all).each{|u| #do something with u} create_table "products", :force => true do |t| t.column "name", :text t.column "description", :text t.column "price", :decimal, :precision => 9, :scale => 2 t.column "category_id", :integer end #the rails 2.0 way: create_table :people do |t| t.integer :account_id t.string :first_name, :last_name, :null => false t.text :description t.references :category # is the equivalent of t.integer :category_id t.timestamps end end def self.down rename_column "users", "hashed_password", "password" add_column "users", "email", :string drop_table "products" end end Find Highest version: script/runner "puts ActiveRecord::Migrator.current_version" Database Mapping Rails db2 mysql openbase Oracle :binary blob(32678) blob object blob :boolean decimal(1) tinyint(1) boolean number(10) :date date date date date :datetime timestamp datetime datetime date :decimal decimal decimal decimal decimal :float float float float number :integer int int(11) integer number(38) :string varchar(255) varchar(255) char(4096) varchar2(255) :text clob(32768) text text clob :time time time time date :timestamp timestamp datetime timestamp date Rails postgresql sqlite sqlserver Sybase :binary bytea blob image image :boolean boolean boolean bit bit :date date date datetime datetime :datetime timestamp datetime datetime datetime :decimal decimal decimal decimal decimal :float float float float(8) float(8) :integer integer integer int int :string * varchar(255) varchar(255) varchar(255) :text text text text text :time time datetime datetime time :timestamp timestamp datetime datetime timestamp

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