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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
# def tables(name = nil) end
# Returns an array of indexes for the given table.
# def indexes(table_name, name = nil) 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
# Creates a new table
# 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() yields a TableDefinition instance
# create_table(:suppliers) do |t|
# t.column :name, :string, :limit => 60
# # Other fields here
# end
#
# === Regular form
# create_table(:suppliers)
# add_column(:suppliers, :name, :string, {:limit => 60})
#
# The +options+ hash can include the following keys:
# [<tt>:id</tt>]
# Set to true or false to add/not add a primary key column
# automatically. Defaults to true.
# [<tt>:primary_key</tt>]
# The name of the primary key, if one is to be added automatically.
# Defaults to +id+.
# [<tt>:options</tt>]
# Any extra options you want appended to the table definition.
# [<tt>:temporary</tt>]
# Make a temporary table.
#
# ===== 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_join (
# category_id int,
# supplier_id int
# )
#
# See also TableDefinition#column for details on how to create columns.
def create_table(name, options = {})
table_definition = TableDefinition.new(self)
table_definition.primary_key(options[:primary_key] || "id") unless options[:id] == false
yield table_definition
if options[:force]
drop_table(name) rescue nil
end
create_sql = "CREATE#{' TEMPORARY' if options[:temporary]} TABLE "
create_sql << "#{name} ("
create_sql << table_definition.to_sql
create_sql << ") #{options[:options]}"
execute create_sql
end
# Renames a table.
# ===== Example
# rename_table('octopuses', 'octopi')
def rename_table(name, new_name)
raise NotImplementedError, "rename_table is not implemented"
end
# Drops a table from the database.
def drop_table(name)
execute "DROP 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 #{table_name} ADD #{column_name} #{type_to_sql(type, options[:limit])}"
add_column_options!(add_column_sql, options)
execute(add_column_sql)
end
# Removes the column from the table definition.
# ===== Examples
# remove_column(:suppliers, :qualification)
def remove_column(table_name, column_name)
execute "ALTER TABLE #{table_name} DROP #{column_name}"
end
# 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 apppropriate 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 names,
# unless you pass +:name+ as an option.
#
# ===== 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_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)
def add_index(table_name, column_name, options = {})
index_name = "#{table_name}_#{Array(column_name).first}_index"
if Hash === options # legacy support, since this param was a string
index_type = options[:unique] ? "UNIQUE" : ""
index_name = options[:name] || index_name
else
index_type = options
end
execute "CREATE #{index_type} INDEX #{index_name} ON #{table_name} (#{Array(column_name).join(", ")})"
end
# Remove the given index from the table.
#
# Remove the suppliers_name_index in the suppliers table (legacy support, use the second or third forms).
# remove_index :suppliers, :name
# Remove the index named accounts_branch_id in the accounts table.
# remove_index :accounts, :column => :branch_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 = {})
if Hash === options # legacy support
if options[:column]
index_name = "#{table_name}_#{options[:column]}_index"
elsif options[:name]
index_name = options[:name]
else
raise ArgumentError, "You must specify the index name"
end
else
index_name = "#{table_name}_#{options}_index"
end
execute "DROP INDEX #{index_name} ON #{table_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
# Should not be called normally, but this operation is non-destructive.
# The migrations module handles this automatically.
def initialize_schema_information
begin
execute "CREATE TABLE #{ActiveRecord::Migrator.schema_info_table_name} (version #{type_to_sql(:integer)})"
execute "INSERT INTO #{ActiveRecord::Migrator.schema_info_table_name} (version) VALUES(0)"
rescue ActiveRecord::StatementInvalid
# Schema has been intialized
end
end
def dump_schema_information #:nodoc:
begin
if (current_schema = ActiveRecord::Migrator.current_version) > 0
return "INSERT INTO #{ActiveRecord::Migrator.schema_info_table_name} (version) VALUES (#{current_schema});"
end
rescue ActiveRecord::StatementInvalid
# No Schema Info
end
end
def type_to_sql(type, limit = nil) #:nodoc:
native = native_database_types[type]
limit ||= native[:limit]
column_type_sql = native[:name]
column_type_sql << "(#{limit})" if limit
column_type_sql
end
def add_column_options!(sql, options) #:nodoc:
sql << " NOT NULL" if options[:null] == false
sql << " DEFAULT #{quote(options[:default], options[:column])}" unless options[:default].nil?
end
end
end
end
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