Class: Sequel::Schema::Generator

Inherits:
Object
  • Object
show all
Defined in:
lib/sequel/lib/sequel/database/schema_generator.rb,
lib/sequel/lib/sequel/extensions/schema_dumper.rb

Overview

Schema::Generator is an internal class that the user is not expected to instantiate directly. Instances are created by Database#create_table. It is used to specify table creation parameters. It takes a Database object and a block of column/index/constraint specifications, and gives the Database a table description, which the database uses to create a table.

Schema::Generator has some methods but also includes method_missing, allowing users to specify column type as a method instead of using the column method, which makes for a nicer DSL.

Constant Summary collapse

GENERIC_TYPES =

Classes specifying generic types that Sequel will convert to database-specific types.

[String, Integer, Fixnum, Bignum, Float, Numeric, BigDecimal,
Date, DateTime, Time, File, TrueClass, FalseClass]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(db, &block) ⇒ Generator

Set the database in which to create the table, and evaluate the block in the context of this object.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 31

def initialize(db, &block)
  @db = db
  @columns = []
  @indexes = []
  @constraints = []
  @primary_key = nil
  instance_eval(&block) if block
  @columns.unshift(@primary_key) if @primary_key && !has_column?(primary_key_name)
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(type, name = nil, opts = {}) ⇒ Object

Add a column with the given type, name, and opts to the DDL. See column for available options.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 135

def method_missing(type, name = nil, opts = {})
  name ? column(name, type, opts) : super
end

Instance Attribute Details

#columnsObject (readonly)

Return the columns created by this generator


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 21

def columns
  @columns
end

#constraintsObject (readonly)

Return the constraints created by this generator


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 24

def constraints
  @constraints
end

#indexesObject (readonly)

Return the indexes created by this generator


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 27

def indexes
  @indexes
end

Class Method Details

.add_type_method(*types) ⇒ Object

Add a method for each of the given types that creates a column with that type as a constant. Types given should either already be constants/classes or a capitalized string/symbol with the same name as a constant/class.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 45

def self.add_type_method(*types)
  types.each do |type|
    class_eval("def #{type}(name, opts={}); column(name, #{type}, opts); end", __FILE__, __LINE__)
  end
end

Instance Method Details

#check(*args, &block) ⇒ Object

Add a unnamed constraint to the DDL, specified by the given block or args.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 53

def check(*args, &block)
  constraint(nil, *args, &block)
end

#column(name, type, opts = {}) ⇒ Object

Add a column with the given name, type, and opts to the DDL.

You can also create columns via method missing, so the following are equivalent:

column :number, :integer
integer :number

The following options are supported:

  • :default - The default value for the column.

  • :index - Create an index on this column.

  • :key - For foreign key columns, the column in the associated table that this column references. Unnecessary if this column references the primary key of the associated table.

  • :null - Mark the column as allowing NULL values (if true), or not allowing NULL values (if false). If unspecified, will default to whatever the database default is.

  • :on_delete - Specify the behavior of this column when being deleted. See Dataset#on_delete_clause for options.

  • :on_update - Specify the behavior of this column when being updated. See Schema::SQL#on_delete_clause for options.

  • :size - The size of the column, generally used with string columns to specify the maximum number of characters the column will hold.

  • :unique - Mark the column as unique, generally has the same effect as creating a unique index on the column.

  • :unsigned - Make the column type unsigned, only useful for integer columns.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 85

def column(name, type, opts = {})
  columns << {:name => name, :type => type}.merge(opts)
  index(name) if opts[:index]
end

#constraint(name, *args, &block) ⇒ Object

Adds a named constraint (or unnamed if name is nil) to the DDL, with the given block or args.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 92

def constraint(name, *args, &block)
  constraints << {:name => name, :type => :check, :check => block || args}
end

#dump_columnsObject

Dump this generator's columns to a string that could be evaled inside another instance to represent the same columns


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# File 'lib/sequel/lib/sequel/extensions/schema_dumper.rb', line 180

def dump_columns
  strings = []
  cols = columns.dup
  if pkn = primary_key_name
    cols.delete_if{|x| x[:name] == pkn}
    pk = @primary_key.dup
    pkname = pk.delete(:name)
    @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
    strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
  end
  cols.each do |c|
    c = c.dup
    name = c.delete(:name)
    type = c.delete(:type)
    opts = opts_inspect(c)
    strings << if type.is_a?(Class)
      "#{type.name} #{name.inspect}#{opts}"
    else
      "column #{name.inspect}, #{type.inspect}#{opts}"
    end
  end
  strings.join("\n")
end

#dump_constraintsObject

Dump this generator's constraints to a string that could be evaled inside another instance to represent the same constraints


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# File 'lib/sequel/lib/sequel/extensions/schema_dumper.rb', line 206

def dump_constraints
  constraints.map do |c|
    c = c.dup
    type = c.delete(:type)
    case type
    when :check
      raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
      name = c.delete(:name)
      if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
        "check #{c[:check].first.inspect[1...-1]}"
      else
        "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
      end
    else
      cols = c.delete(:columns)
      "#{type} #{cols.inspect}#{opts_inspect(c)}"
    end
  end.join("\n")
end

#dump_indexes(options = {}) ⇒ Object

Dump this generator's indexes to a string that could be evaled inside another instance to represent the same indexes. Options:

  • :add_index - Use add_index instead of index, so the methods can be called outside of a generator but inside a migration. The value of this option should be the table name to use.

  • :drop_index - Same as add_index, but create drop_index statements.

  • :ignore_errors - Add the ignore_errors option to the outputted indexes


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# File 'lib/sequel/lib/sequel/extensions/schema_dumper.rb', line 233

def dump_indexes(options={})
  indexes.map do |c|
    c = c.dup
    cols = c.delete(:columns)
    if table = options[:add_index] || options[:drop_index]
      "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}"
    else
      "index #{cols.inspect}#{opts_inspect(c)}"
    end
  end.join("\n")
end

#foreign_key(name, table = nil, opts = {}) ⇒ Object

Add a foreign key in the table that references another table to the DDL. See column for available options.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 98

def foreign_key(name, table=nil, opts = {})
  opts = case table
  when Hash
    table.merge(opts)
  when Symbol
    opts.merge(:table=>table)
  when NilClass
    opts
  else
    raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil")
  end
  return composite_foreign_key(name, opts) if name.is_a?(Array)
  column(name, Integer, opts)
end

#full_text_index(columns, opts = {}) ⇒ Object

Add a full text index on the given columns to the DDL.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 114

def full_text_index(columns, opts = {})
  index(columns, opts.merge(:type => :full_text))
end

#has_column?(name) ⇒ Boolean

True if the DDL includes the creation of a column with the given name.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 119

def has_column?(name)
  columns.any?{|c| c[:name] == name}
end

#index(columns, opts = {}) ⇒ Object

Add an index on the given column(s) with the given options to the DDL. The available options are:

  • :type - The type of index to use (only supported by some databases)

  • :unique - Make the index unique, so duplicate values are not allowed.

  • :where - Create a partial index (only supported by some databases)


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 129

def index(columns, opts = {})
  indexes << {:columns => Array(columns)}.merge(opts)
end

#primary_key(name, *args) ⇒ Object

Add primary key information to the DDL. Takes between one and three arguments. The last one is an options hash as for Generator#column. The first one distinguishes two modes: an array of existing column names adds a composite primary key constraint. A single symbol adds a new column of that name and makes it the primary key. In that case the optional middle argument denotes the type.

Examples:

primary_key(:id)
primary_key(:zip_code, :null => false)
primary_key([:street_number, :house_number])
primary_key(:id, :string, :auto_increment => false)

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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 151

def primary_key(name, *args)
  return composite_primary_key(name, *args) if name.is_a?(Array)
  @primary_key = @db.serial_primary_key_options.merge({:name => name})
  
  if opts = args.pop
    opts = {:type => opts} unless opts.is_a?(Hash)
    if type = args.pop
      opts.merge!(:type => type)
    end
    @primary_key.merge!(opts)
  end
  @primary_key
end

#primary_key_nameObject

The name of the primary key for this table, if it has a primary key.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 166

def primary_key_name
  @primary_key[:name] if @primary_key
end

#spatial_index(columns, opts = {}) ⇒ Object

Add a spatial index on the given columns to the DDL.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 171

def spatial_index(columns, opts = {})
  index(columns, opts.merge(:type => :spatial))
end

#unique(columns, opts = {}) ⇒ Object

Add a unique constraint on the given columns to the DDL.


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# File 'lib/sequel/lib/sequel/database/schema_generator.rb', line 176

def unique(columns, opts = {})
  constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
end