require 'active_support/core_ext/array/wrap'
module ActiveRecord
module ConnectionAdapters # :nodoc:
module SchemaStatements
# Returns a Hash of mappings from the abstract data types to the native
# database types. See TableDefinition#column for details on the recognized
# abstract data types.
def native_database_types
{}
end
# Truncates a table alias according to the limits of the current adapter.
def table_alias_for(table_name)
table_name[0..table_alias_length-1].gsub(/\./, '_')
end
# def tables(name = nil) end
def table_exists?(table_name)
tables.include?(table_name.to_s)
end
# Returns an array of indexes for the given table.
# def indexes(table_name, name = nil) end
# Checks to see if an index exists on a table for a given index definition
#
# === Examples
# # Check an index exists
# index_exists?(:suppliers, :company_id)
#
# # Check an index on multiple columns exists
# index_exists?(:suppliers, [:company_id, :company_type])
#
# # Check a unique index exists
# index_exists?(:suppliers, :company_id, :unique => true)
#
# # Check an index with a custom name exists
# index_exists?(:suppliers, :company_id, :name => "idx_company_id"
def index_exists?(table_name, column_name, options = {})
column_names = Array.wrap(column_name)
index_name = options.key?(:name) ? options[:name].to_s : index_name(table_name, :column => column_names)
if options[:unique]
indexes(table_name).any?{ |i| i.unique && i.name == index_name }
else
indexes(table_name).any?{ |i| i.name == index_name }
end
end
# Returns an array of Column objects for the table specified by +table_name+.
# See the concrete implementation for details on the expected parameter values.
def columns(table_name, name = nil) end
# Checks to see if a column exists in a given table.
#
# === Examples
# # Check a column exists
# column_exists?(:suppliers, :name)
#
# # Check a column exists of a particular type
# column_exists?(:suppliers, :name, :string)
#
# # Check a column exists with a specific definition
# column_exists?(:suppliers, :name, :string, :limit => 100)
def column_exists?(table_name, column_name, type = nil, options = {})
columns(table_name).any?{ |c| c.name == column_name.to_s &&
(!type || c.type == type) &&
(!options[:limit] || c.limit == options[:limit]) &&
(!options[:precision] || c.precision == options[:precision]) &&
(!options[:scale] || c.scale == options[:scale]) }
end
# Creates a new table with the name +table_name+. +table_name+ may either
# be a String or a Symbol.
#
# There are two ways to work with +create_table+. You can use the block
# form or the regular form, like this:
#
# === Block form
# # create_table() passes a TableDefinition object to the block.
# # This form will not only create the table, but also columns for the
# # table.
#
# create_table(:suppliers) do |t|
# t.column :name, :string, :limit => 60
# # Other fields here
# end
#
# === Block form, with shorthand
# # You can also use the column types as method calls, rather than calling the column method.
# create_table(:suppliers) do |t|
# t.string :name, :limit => 60
# # Other fields here
# end
#
# === Regular form
# # Creates a table called 'suppliers' with no columns.
# create_table(:suppliers)
# # Add a column to 'suppliers'.
# add_column(:suppliers, :name, :string, {:limit => 60})
#
# The +options+ hash can include the following keys:
# [<tt>:id</tt>]
# Whether to automatically add a primary key column. Defaults to true.
# Join tables for +has_and_belongs_to_many+ should set it to false.
# [<tt>:primary_key</tt>]
# The name of the primary key, if one is to be added automatically.
# Defaults to +id+. If <tt>:id</tt> is false this option is ignored.
#
# Also note that this just sets the primary key in the table. You additionally
# need to configure the primary key in the model via the +set_primary_key+ macro.
# Models do NOT auto-detect the primary key from their table definition.
#
# [<tt>:options</tt>]
# Any extra options you want appended to the table definition.
# [<tt>:temporary</tt>]
# Make a temporary table.
# [<tt>:force</tt>]
# Set to true to drop the table before creating it.
# Defaults to false.
#
# ===== Examples
# ====== Add a backend specific option to the generated SQL (MySQL)
# create_table(:suppliers, :options => 'ENGINE=InnoDB DEFAULT CHARSET=utf8')
# generates:
# CREATE TABLE suppliers (
# id int(11) DEFAULT NULL auto_increment PRIMARY KEY
# ) ENGINE=InnoDB DEFAULT CHARSET=utf8
#
# ====== Rename the primary key column
# create_table(:objects, :primary_key => 'guid') do |t|
# t.column :name, :string, :limit => 80
# end
# generates:
# CREATE TABLE objects (
# guid int(11) DEFAULT NULL auto_increment PRIMARY KEY,
# name varchar(80)
# )
#
# ====== Do not add a primary key column
# create_table(:categories_suppliers, :id => false) do |t|
# t.column :category_id, :integer
# t.column :supplier_id, :integer
# end
# generates:
# CREATE TABLE categories_suppliers (
# category_id int,
# supplier_id int
# )
#
# See also TableDefinition#column for details on how to create columns.
def create_table(table_name, options = {})
td = table_definition
td.primary_key(options[:primary_key] || Base.get_primary_key(table_name.to_s.singularize)) unless options[:id] == false
yield td if block_given?
if options[:force] && table_exists?(table_name)
drop_table(table_name, options)
end
create_sql = "CREATE#{' TEMPORARY' if options[:temporary]} TABLE "
create_sql << "#{quote_table_name(table_name)} ("
create_sql << td.to_sql
create_sql << ") #{options[:options]}"
execute create_sql
end
# A block for changing columns in +table+.
#
# === Example
# # change_table() yields a Table instance
# change_table(:suppliers) do |t|
# t.column :name, :string, :limit => 60
# # Other column alterations here
# end
#
# ===== Examples
# ====== Add a column
# change_table(:suppliers) do |t|
# t.column :name, :string, :limit => 60
# end
#
# ====== Add 2 integer columns
# change_table(:suppliers) do |t|
# t.integer :width, :height, :null => false, :default => 0
# end
#
# ====== Add created_at/updated_at columns
# change_table(:suppliers) do |t|
# t.timestamps
# end
#
# ====== Add a foreign key column
# change_table(:suppliers) do |t|
# t.references :company
# end
#
# Creates a <tt>company_id(integer)</tt> column
#
# ====== Add a polymorphic foreign key column
# change_table(:suppliers) do |t|
# t.belongs_to :company, :polymorphic => true
# end
#
# Creates <tt>company_type(varchar)</tt> and <tt>company_id(integer)</tt> columns
#
# ====== Remove a column
# change_table(:suppliers) do |t|
# t.remove :company
# end
#
# ====== Remove several columns
# change_table(:suppliers) do |t|
# t.remove :company_id
# t.remove :width, :height
# end
#
# ====== Remove an index
# change_table(:suppliers) do |t|
# t.remove_index :company_id
# end
#
# See also Table for details on
# all of the various column transformation
def change_table(table_name)
yield Table.new(table_name, self)
end
# Renames a table.
# ===== Example
# rename_table('octopuses', 'octopi')
def rename_table(table_name, new_name)
raise NotImplementedError, "rename_table is not implemented"
end
# Drops a table from the database.
def drop_table(table_name, options = {})
execute "DROP TABLE #{quote_table_name(table_name)}"
end
# Adds a new column to the named table.
# See TableDefinition#column for details of the options you can use.
def add_column(table_name, column_name, type, options = {})
add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
add_column_options!(add_column_sql, options)
execute(add_column_sql)
end
# Removes the column(s) from the table definition.
# ===== Examples
# remove_column(:suppliers, :qualification)
# remove_columns(:suppliers, :qualification, :experience)
def remove_column(table_name, *column_names)
raise ArgumentError.new("You must specify at least one column name. Example: remove_column(:people, :first_name)") if column_names.empty?
column_names.flatten.each do |column_name|
execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{quote_column_name(column_name)}"
end
end
alias :remove_columns :remove_column
# Changes the column's definition according to the new options.
# See TableDefinition#column for details of the options you can use.
# ===== Examples
# change_column(:suppliers, :name, :string, :limit => 80)
# change_column(:accounts, :description, :text)
def change_column(table_name, column_name, type, options = {})
raise NotImplementedError, "change_column is not implemented"
end
# Sets a new default value for a column. If you want to set the default
# value to +NULL+, you are out of luck. You need to
# DatabaseStatements#execute the appropriate SQL statement yourself.
# ===== Examples
# change_column_default(:suppliers, :qualification, 'new')
# change_column_default(:accounts, :authorized, 1)
def change_column_default(table_name, column_name, default)
raise NotImplementedError, "change_column_default is not implemented"
end
# Renames a column.
# ===== Example
# rename_column(:suppliers, :description, :name)
def rename_column(table_name, column_name, new_column_name)
raise NotImplementedError, "rename_column is not implemented"
end
# Adds a new index to the table. +column_name+ can be a single Symbol, or
# an Array of Symbols.
#
# The index will be named after the table and the first column name,
# unless you pass <tt>:name</tt> as an option.
#
# When creating an index on multiple columns, the first column is used as a name
# for the index. For example, when you specify an index on two columns
# [<tt>:first</tt>, <tt>:last</tt>], the DBMS creates an index for both columns as well as an
# index for the first column <tt>:first</tt>. Using just the first name for this index
# makes sense, because you will never have to create a singular index with this
# name.
#
# ===== Examples
#
# ====== Creating a simple index
# add_index(:suppliers, :name)
# generates
# CREATE INDEX suppliers_name_index ON suppliers(name)
#
# ====== Creating a unique index
# add_index(:accounts, [:branch_id, :party_id], :unique => true)
# generates
# CREATE UNIQUE INDEX accounts_branch_id_party_id_index ON accounts(branch_id, party_id)
#
# ====== Creating a named index
# add_index(:accounts, [:branch_id, :party_id], :unique => true, :name => 'by_branch_party')
# generates
# CREATE UNIQUE INDEX by_branch_party ON accounts(branch_id, party_id)
#
# ====== Creating an index with specific key length
# add_index(:accounts, :name, :name => 'by_name', :length => 10)
# generates
# CREATE INDEX by_name ON accounts(name(10))
#
# add_index(:accounts, [:name, :surname], :name => 'by_name_surname', :length => {:name => 10, :surname => 15})
# generates
# CREATE INDEX by_name_surname ON accounts(name(10), surname(15))
#
# Note: SQLite doesn't support index length
def add_index(table_name, column_name, options = {})
column_names = Array.wrap(column_name)
index_name = index_name(table_name, :column => column_names)
if Hash === options # legacy support, since this param was a string
index_type = options[:unique] ? "UNIQUE" : ""
index_name = options[:name].to_s if options.key?(:name)
else
index_type = options
end
if index_name.length > index_name_length
raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{index_name_length} characters"
end
if index_name_exists?(table_name, index_name, false)
raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' already exists"
end
quoted_column_names = quoted_columns_for_index(column_names, options).join(", ")
execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{quoted_column_names})"
end
# Remove the given index from the table.
#
# Remove the suppliers_name_index in the suppliers table.
# remove_index :suppliers, :name
# Remove the index named accounts_branch_id_index in the accounts table.
# remove_index :accounts, :column => :branch_id
# Remove the index named accounts_branch_id_party_id_index in the accounts table.
# remove_index :accounts, :column => [:branch_id, :party_id]
# Remove the index named by_branch_party in the accounts table.
# remove_index :accounts, :name => :by_branch_party
def remove_index(table_name, options = {})
index_name = index_name(table_name, options)
unless index_name_exists?(table_name, index_name, true)
raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' does not exist"
end
remove_index!(table_name, index_name)
end
def remove_index!(table_name, index_name) #:nodoc:
execute "DROP INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)}"
end
# Rename an index.
#
# Rename the index_people_on_last_name index to index_users_on_last_name
# rename_index :people, 'index_people_on_last_name', 'index_users_on_last_name'
def rename_index(table_name, old_name, new_name)
# this is a naive implementation; some DBs may support this more efficiently (Postgres, for instance)
old_index_def = indexes(table_name).detect { |i| i.name == old_name }
return unless old_index_def
remove_index(table_name, :name => old_name)
add_index(table_name, old_index_def.columns, :name => new_name, :unique => old_index_def.unique)
end
def index_name(table_name, options) #:nodoc:
if Hash === options # legacy support
if options[:column]
"index_#{table_name}_on_#{Array.wrap(options[:column]) * '_and_'}"
elsif options[:name]
options[:name]
else
raise ArgumentError, "You must specify the index name"
end
else
index_name(table_name, :column => options)
end
end
# Verify the existence of an index with a given name.
#
# The default argument is returned if the underlying implementation does not define the indexes method,
# as there's no way to determine the correct answer in that case.
def index_name_exists?(table_name, index_name, default)
return default unless respond_to?(:indexes)
index_name = index_name.to_s
indexes(table_name).detect { |i| i.name == index_name }
end
# Returns a string of <tt>CREATE TABLE</tt> SQL statement(s) for recreating the
# entire structure of the database.
def structure_dump
end
def dump_schema_information #:nodoc:
sm_table = ActiveRecord::Migrator.schema_migrations_table_name
migrated = select_values("SELECT version FROM #{sm_table}")
migrated.map { |v| "INSERT INTO #{sm_table} (version) VALUES ('#{v}');" }.join("\n\n")
end
# Should not be called normally, but this operation is non-destructive.
# The migrations module handles this automatically.
def initialize_schema_migrations_table
sm_table = ActiveRecord::Migrator.schema_migrations_table_name
if table_exists?(sm_table)
cols = columns(sm_table).collect { |col| col.name }
unless cols.include?("migrated_at")
add_column sm_table, :migrated_at, :datetime
update "UPDATE #{quote_table_name(sm_table)} SET migrated_at = '#{quoted_date(Time.now)}' WHERE migrated_at IS NULL"
change_column sm_table, :migrated_at, :datetime, :null => false
end
unless cols.include?("name")
add_column sm_table, :name, :string, :null => false, :default => ""
end
else
create_table(sm_table, :id => false) do |schema_migrations_table|
schema_migrations_table.column :version, :string, :null => false
schema_migrations_table.column :name, :string, :null => false, :default => ""
schema_migrations_table.column :migrated_at, :datetime, :null => false
end
add_index sm_table, :version, :unique => true,
:name => "#{Base.table_name_prefix}unique_schema_migrations#{Base.table_name_suffix}"
# Backwards-compatibility: if we find schema_info, assume we've
# migrated up to that point:
si_table = Base.table_name_prefix + 'schema_info' + Base.table_name_suffix
if table_exists?(si_table)
old_version = select_value("SELECT version FROM #{quote_table_name(si_table)}").to_i
assume_migrated_upto_version(old_version)
drop_table(si_table)
end
end
end
def assume_migrated_upto_version(version, migrations_path = ActiveRecord::Migrator.migrations_path)
version = version.to_i
sm_table = quote_table_name(ActiveRecord::Migrator.schema_migrations_table_name)
migrated = select_values("SELECT version FROM #{sm_table}").map { |v| v.to_i }
versions = Dir["#{migrations_path}/[0-9]*_*.rb"].map do |filename|
filename.split('/').last.split('_').first.to_i
end
unless migrated.include?(version)
execute "INSERT INTO #{sm_table} (version) VALUES ('#{version}')"
end
inserted = Set.new
(versions - migrated).each do |v|
if inserted.include?(v)
raise "Duplicate migration #{v}. Please renumber your migrations to resolve the conflict."
elsif v < version
execute "INSERT INTO #{sm_table} (version) VALUES ('#{v}')"
inserted << v
end
end
end
def type_to_sql(type, limit = nil, precision = nil, scale = nil) #:nodoc:
if native = native_database_types[type]
column_type_sql = (native.is_a?(Hash) ? native[:name] : native).dup
if type == :decimal # ignore limit, use precision and scale
scale ||= native[:scale]
if precision ||= native[:precision]
if scale
column_type_sql << "(#{precision},#{scale})"
else
column_type_sql << "(#{precision})"
end
elsif scale
raise ArgumentError, "Error adding decimal column: precision cannot be empty if scale if specified"
end
elsif (type != :primary_key) && (limit ||= native.is_a?(Hash) && native[:limit])
column_type_sql << "(#{limit})"
end
column_type_sql
else
type
end
end
def add_column_options!(sql, options) #:nodoc:
sql << " DEFAULT #{quote(options[:default], options[:column])}" if options_include_default?(options)
# must explicitly check for :null to allow change_column to work on migrations
if options[:null] == false
sql << " NOT NULL"
end
end
# SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
# Both PostgreSQL and Oracle overrides this for custom DISTINCT syntax.
#
# distinct("posts.id", "posts.created_at desc")
def distinct(columns, order_by)
"DISTINCT #{columns}"
end
# Adds timestamps (created_at and updated_at) columns to the named table.
# ===== Examples
# add_timestamps(:suppliers)
def add_timestamps(table_name)
add_column table_name, :created_at, :datetime
add_column table_name, :updated_at, :datetime
end
# Removes the timestamp columns (created_at and updated_at) from the table definition.
# ===== Examples
# remove_timestamps(:suppliers)
def remove_timestamps(table_name)
remove_column table_name, :updated_at
remove_column table_name, :created_at
end
protected
# Overridden by the mysql adapter for supporting index lengths
def quoted_columns_for_index(column_names, options = {})
column_names.map {|name| quote_column_name(name) }
end
def options_include_default?(options)
options.include?(:default) && !(options[:null] == false && options[:default].nil?)
end
private
def table_definition
TableDefinition.new(self)
end
end
end
end
