Class | Sequel::Schema::Generator
In: | lib/sequel/database/schema_generator.rb lib/sequel/extensions/schema_dumper.rb
Parent: | Object

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.

For more information on Sequel‘s support for schema modification, see the "Migrations and Schema Modification" guide.

### Methods

add_type_method check column constraint dump_columns dump_constraints dump_indexes foreign_key full_text_index has_column? index method_missing new primary_key primary_key_name spatial_index unique

### Constants

GENERIC_TYPES | = | [String, Integer, Fixnum, Bignum, Float, Numeric, BigDecimal, Date, DateTime, Time, File, TrueClass, FalseClass] |  | Classes specifying generic types that Sequel will convert to database-specific types.

### Attributes

columns | [R] | Return the column hashes created by this generator
constraints | [R] | Return the constraint hashes created by this generator
indexes | [R] | Return the index hashes created by this generator

### Public Class methods

add_type_method(*types)

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.

[Source]

        # File lib/sequel/database/schema_generator.rb, line 47
    47:       def self.add_type_method(*types)
    48:         types.each do |type|
    49:           class_eval("def #{type}(name, opts={}); column(name, #{type}, opts); end", __FILE__, __LINE__)
    50:         end
    51:       end

new(db, &block)

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

[Source]

        # File lib/sequel/database/schema_generator.rb, line 33
    33:       def initialize(db, &block)
    34:         @db = db
    35:         @columns = []
    36:         @indexes = []
    37:         @constraints = []
    38:         @primary_key = nil
    39:         instance_eval(&block) if block
    40:         @columns.unshift(@primary_key) if @primary_key && !has_column?(primary_key_name)
    41:       end

### Public Instance methods

check(*args, &block)

Add an unnamed constraint to the DDL, specified by the given block or args:

      check(:num=>1..5) # CHECK num >= 1 AND num <= 5
      check{num > 5} # CHECK num > 5

[Source]

        # File lib/sequel/database/schema_generator.rb, line 58
    58:       def check(*args, &block)
    59:         constraint(nil, *args, &block)
    60:       end

column(name, type, opts = {})

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

      column :num, :integer
      # num INTEGER

      column :name, String, :null=>false, :default=>'a'
      # name varchar(255) NOT NULL DEFAULT 'a'

      inet :ip
      # ip inet

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.
:deferrable : | This ensure Referential Integrity will work even if reference table will use for its foreign key a value that does not exists(yet) on referenced table. Basically it adds DEFERRABLE INITIALLY DEFERRED on key creation.
: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, except if you are using MySQL.
: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 (:restrict, cascade, :set_null, :set_default, :no_action).
:on_update : | Specify the behavior of this column when being updated (:restrict, cascade, :set_null, :set_default, :no_action).
:primary_key : | Make the column as a single primary key column. This should only be used if you have a single, nonautoincrementing primary key column.
:size : | The size of the column, generally used with string columns to specify the maximum number of characters the column will hold. An array of two integers can be provided to set the size and the precision, respectively, of decimal columns.
: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.

[Source]

         # File lib/sequel/database/schema_generator.rb, line 108
    108:       def column(name, type, opts = {})
    109:         columns << {:name => name, :type => type}.merge(opts)
    110:         index(name) if opts[:index]
    111:       end

constraint(name, *args, &block)

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

      constraint(:blah, :num=>1..5) # CONSTRAINT blah CHECK num >= 1 AND num <= 5
      check(:foo){num > 5} # CONSTRAINT foo CHECK num > 5

[Source]

         # File lib/sequel/database/schema_generator.rb, line 118
    118:       def constraint(name, *args, &block)
    119:         constraints << {:name => name, :type => :check, :check => block || args}
    120:       end

dump_columns()

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

[Source]

         # File lib/sequel/extensions/schema_dumper.rb, line 192
    192:       def dump_columns
    193:         strings = []
    194:         cols = columns.dup
    195:         if pkn = primary_key_name
    196:           cols.delete_if{|x| x[:name] == pkn}
    197:           pk = @primary_key.dup
    198:           pkname = pk.delete(:name)
    199:           @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
    200:           strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
    201:         end
    202:         cols.each do |c|
    203:           c = c.dup
    204:           name = c.delete(:name)
    205:           type = c.delete(:type)
    206:           opts = opts_inspect(c)
    207:           strings << if type.is_a?(Class)
    208:             "#{type.name} #{name.inspect}#{opts}"
    209:           else
    210:             "column #{name.inspect}, #{type.inspect}#{opts}"
    211:           end
    212:         end
    213:         strings.join("\n")
    214:       end

dump_constraints()

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

[Source]

         # File lib/sequel/extensions/schema_dumper.rb, line 218
    218:       def dump_constraints
    219:         cs = constraints.map do |c|
    220:           c = c.dup
    221:           type = c.delete(:type)
    222:           case type
    223:           when :check
    224:             raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
    225:             name = c.delete(:name)
    226:             if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
    227:               "check #{c[:check].first.inspect[1...-1]}"
    228:             else
    229:               "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
    230:             end
    231:           else
    232:             cols = c.delete(:columns)
    233:             "#{type} #{cols.inspect}#{opts_inspect(c)}"
    234:           end
    235:         end
    236:         cs.join("\n")
    237:       end

dump_indexes(options={})

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

[Source]

         # File lib/sequel/extensions/schema_dumper.rb, line 246
    246:       def dump_indexes(options={})
    247:         is = indexes.map do |c|
    248:           c = c.dup
    249:           cols = c.delete(:columns)
    250:           if table = options[:add_index] || options[:drop_index]
    251:             "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}"
    252:           else
    253:             "index #{cols.inspect}#{opts_inspect(c)}"
    254:           end
    255:         end
    256:         is.join("\n")
    257:       end

foreign_key(name, table=nil, opts = {})

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

      foreign_key(:artist_id) # artist_id INTEGER
      foreign_key(:artist_id, :artists) # artist_id INTEGER REFERENCES artists
      foreign_key(:artist_id, :artists, :key=>:id) # artist_id INTEGER REFERENCES artists(id)

If you want a foreign key constraint without adding a column (usually because it is a composite foreign key), you can provide an array of columns as the first argument, and you can provide the :name option to name the constraint:

      foreign_key([:artist_name, :artist_location], :artists, :name=>:artist_fk)
      # ADD CONSTRAINT artist_fk FOREIGN KEY (artist_name, artist_location) REFERENCES artists

[Source]

         # File lib/sequel/database/schema_generator.rb, line 135
    135:       def foreign_key(name, table=nil, opts = {})
    136:         opts = case table
    137:         when Hash
    138:           table.merge(opts)
    139:         when Symbol
    140:           opts.merge(:table=>table)
    141:         when NilClass
    142:           opts
    143:         else
    144:           raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil")
    145:         end
    146:         return composite_foreign_key(name, opts) if name.is_a?(Array)
    147:         column(name, Integer, opts)
    148:       end

full_text_index(columns, opts = {})

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 151
    151:       def full_text_index(columns, opts = {})
    152:         index(columns, opts.merge(:type => :full_text))
    153:       end

has_column?(name)

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 156
    156:       def has_column?(name)
    157:         columns.any?{|c| c[:name] == name}
    158:       end

index(columns, opts = {})

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)

      index :name
      # CREATE INDEX table_name_index ON table (name)

      index [:artist_id, :name]
      # CREATE INDEX table_artist_id_name_index ON table (artist_id, name)

[Source]

         # File lib/sequel/database/schema_generator.rb, line 172
    172:       def index(columns, opts = {})
    173:         indexes << {:columns => Array(columns)}.merge(opts)
    174:       end

method_missing(type, name = nil, opts = {})

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 178
    178:       def method_missing(type, name = nil, opts = {})
    179:         name ? column(name, type, opts) : super
    180:       end

primary_key(name, *args)

Adds an autoincrementing primary key column or a primary key constraint to the DDL. To create a constraint, the first argument should be an array of column symbols specifying the primary key columns. To create an autoincrementing primary key column, a single symbol can be used. In both cases, an options hash can be used as the second argument.

If you want to create a primary key column that is not autoincrementing, you should not use this method. Instead, you should use the regular `column` method with a `:primary_key=>true` option.

Examples:

      primary_key(:id)
      primary_key([:street_number, :house_number])

[Source]

         # File lib/sequel/database/schema_generator.rb, line 195
    195:       def primary_key(name, *args)
    196:         return composite_primary_key(name, *args) if name.is_a?(Array)
    197:         @primary_key = @db.serial_primary_key_options.merge({:name => name})
    198:
    199:         if opts = args.pop
    200:           opts = {:type => opts} unless opts.is_a?(Hash)
    201:           if type = args.pop
    202:             opts.merge!(:type => type)
    203:           end
    204:           @primary_key.merge!(opts)
    205:         end
    206:         @primary_key
    207:       end

primary_key_name()

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 210
    210:       def primary_key_name
    211:         @primary_key[:name] if @primary_key
    212:       end

spatial_index(columns, opts = {})

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

[Source]

         # File lib/sequel/database/schema_generator.rb, line 215
    215:       def spatial_index(columns, opts = {})
    216:         index(columns, opts.merge(:type => :spatial))
    217:       end

unique(columns, opts = {})

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

      unique(:name) # UNIQUE (name)

[Source]

         # File lib/sequel/database/schema_generator.rb, line 222
    222:       def unique(columns, opts = {})
    223:         constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
    224:       end

[Validate]