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