Class: Sequel::Schema::Generator
- Defined in:
- lib/sequel/database/schema_generator.rb,
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.
For more information on Sequel’s support for schema modification, see the “Migrations and Schema Modification” guide.
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
-
#columns ⇒ Object
readonly
Return the column hashes created by this generator.
-
#constraints ⇒ Object
readonly
Return the constraint hashes created by this generator.
-
#indexes ⇒ Object
readonly
Return the index hashes created by this generator.
Class Method Summary collapse
-
.add_type_method(*types) ⇒ Object
Add a method for each of the given types that creates a column with that type as a constant.
Instance Method Summary collapse
-
#check(*args, &block) ⇒ Object
Add an unnamed constraint to the DDL, specified by the given block or args:.
-
#column(name, type, opts = {}) ⇒ Object
Add a column with the given name, type, and opts to the DDL.
-
#constraint(name, *args, &block) ⇒ Object
Adds a named constraint (or unnamed if name is nil) to the DDL, with the given block or args.
-
#dump_columns ⇒ Object
Dump this generator’s columns to a string that could be evaled inside another instance to represent the same columns.
-
#dump_constraints ⇒ Object
Dump this generator’s constraints to a string that could be evaled inside another instance to represent the same constraints.
-
#dump_indexes(options = {}) ⇒ Object
Dump this generator’s indexes to a string that could be evaled inside another instance to represent the same indexes.
-
#foreign_key(name, table = nil, opts = {}) ⇒ Object
Add a foreign key in the table that references another table to the DDL.
-
#full_text_index(columns, opts = {}) ⇒ Object
Add a full text index on the given columns to the DDL.
-
#has_column?(name) ⇒ Boolean
True if the DDL includes the creation of a column with the given name.
-
#index(columns, opts = {}) ⇒ Object
Add an index on the given column(s) with the given options to the DDL.
-
#initialize(db, &block) ⇒ Generator
constructor
Set the database in which to create the table, and evaluate the block in the context of this object.
-
#method_missing(type, name = nil, opts = {}) ⇒ Object
Add a column with the given type, name, and opts to the DDL.
-
#primary_key(name, *args) ⇒ Object
Adds an autoincrementing primary key column or a primary key constraint to the DDL.
-
#primary_key_name ⇒ Object
The name of the primary key for this generator, if it has a primary key.
-
#spatial_index(columns, opts = {}) ⇒ Object
Add a spatial index on the given columns to the DDL.
-
#unique(columns, opts = {}) ⇒ Object
Add a unique constraint on the given columns to the DDL.
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/database/schema_generator.rb', line 33 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/database/schema_generator.rb', line 181 def method_missing(type, name = nil, opts = {}) name ? column(name, type, opts) : super end |
Instance Attribute Details
#columns ⇒ Object (readonly)
Return the column hashes created by this generator
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# File 'lib/sequel/database/schema_generator.rb', line 23 def columns @columns end |
#constraints ⇒ Object (readonly)
Return the constraint hashes created by this generator
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# File 'lib/sequel/database/schema_generator.rb', line 26 def constraints @constraints end |
#indexes ⇒ Object (readonly)
Return the index hashes created by this generator
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# File 'lib/sequel/database/schema_generator.rb', line 29 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/database/schema_generator.rb', line 47 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 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
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# File 'lib/sequel/database/schema_generator.rb', line 58 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.
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. If given a hash, use the hash as the options for the index.
- :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.
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# File 'lib/sequel/database/schema_generator.rb', line 109 def column(name, type, opts = {}) columns << {:name => name, :type => type}.merge(opts) if index_opts = opts[:index] index(name, index_opts.is_a?(Hash) ? index_opts : {}) end 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.
constraint(:blah, :num=>1..5) # CONSTRAINT blah CHECK num >= 1 AND num <= 5
check(:foo){num > 5} # CONSTRAINT foo CHECK num > 5
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# File 'lib/sequel/database/schema_generator.rb', line 121 def constraint(name, *args, &block) constraints << {:name => name, :type => :check, :check => block || args} end |
#dump_columns ⇒ Object
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/extensions/schema_dumper.rb', line 367 def dump_columns strings = [] cols = columns.dup cols.each do |x| x.delete(:on_delete) if x[:on_delete] == :no_action x.delete(:on_update) if x[:on_update] == :no_action end if pkn = primary_key_name cols.delete_if{|x| x[:name] == pkn} pk = @primary_key.dup pkname = pk.delete(:name) @db..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) strings << if table = c.delete(:table) c.delete(:type) if c[:type] == Integer || c[:type] == 'integer' "foreign_key #{name.inspect}, #{table.inspect}#{opts_inspect(c)}" else type = c.delete(:type) opts = opts_inspect(c) if type.is_a?(Class) "#{type.name} #{name.inspect}#{opts}" else "column #{name.inspect}, #{type.inspect}#{opts}" end end end strings.join("\n") end |
#dump_constraints ⇒ Object
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/extensions/schema_dumper.rb', line 402 def dump_constraints cs = 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 when :foreign_key c.delete(:on_delete) if c[:on_delete] == :no_action c.delete(:on_update) if c[:on_update] == :no_action c.delete(:deferrable) unless c[:deferrable] cols = c.delete(:columns) table = c.delete(:table) "#{type} #{cols.inspect}, #{table.inspect}#{opts_inspect(c)}" else cols = c.delete(:columns) "#{type} #{cols.inspect}#{opts_inspect(c)}" end end cs.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/extensions/schema_dumper.rb', line 437 def dump_indexes(={}) is = indexes.map do |c| c = c.dup cols = c.delete(:columns) if table = [:add_index] || [:drop_index] "#{[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if [:ignore_errors]}#{opts_inspect(c)}" else "index #{cols.inspect}#{opts_inspect(c)}" end end is.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.
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
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# File 'lib/sequel/database/schema_generator.rb', line 138 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/database/schema_generator.rb', line 154 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/database/schema_generator.rb', line 159 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)
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)
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# File 'lib/sequel/database/schema_generator.rb', line 175 def index(columns, opts = {}) indexes << {:columns => Array(columns)}.merge(opts) end |
#primary_key(name, *args) ⇒ Object
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])
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# File 'lib/sequel/database/schema_generator.rb', line 198 def primary_key(name, *args) return composite_primary_key(name, *args) if name.is_a?(Array) @primary_key = @db..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_name ⇒ Object
The name of the primary key for this generator, if it has a primary key.
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# File 'lib/sequel/database/schema_generator.rb', line 213 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/database/schema_generator.rb', line 218 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.
unique(:name) # UNIQUE (name)
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# File 'lib/sequel/database/schema_generator.rb', line 225 def unique(columns, opts = {}) constraints << {:type => :unique, :columns => Array(columns)}.merge(opts) end |