check(*args, &block)
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Add an unnamed constraint, specified by the given block or args:
check(num: 1..5) # CHECK num >= 1 AND num <= 5
check{num > 5} # CHECK num > 5
def check(*args, &block)
constraint(nil, *args, &block)
end
column(name, type, opts = OPTS)
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Add a column with the given name, type, and opts #
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:
- :collate
-
The collation to use for the column. For backwards compatibility, only
symbols and string values are supported, and they are used verbatim.
However, on PostgreSQL, symbols are literalized as regular identifiers,
since unquoted collations are unlikely to be valid.
- :default
-
The default value for the column.
- :deferrable
-
For foreign key columns, this ensures referential integrity will work even
if referencing table uses a foreign key value that does not yet exist on
referenced table (but will exist before the transaction commits). Basically
it adds DEFERRABLE INITIALLY DEFERRED on key creation. If you use
:immediate as the value, uses DEFERRABLE INITIALLY IMMEDIATE.
- :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). The default is to allow NULL values.
- :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 not be used if
you have a single, nonautoincrementing primary key column (use the #primary_key
method in that case).
- :primary_key_constraint_name
-
The name to give the primary key constraint
- :type
-
Overrides the type given as the argument. Generally not used by column
itself, but can be passed as an option to other methods that call column.
- :unique
-
Mark the column as unique, generally has the same effect as creating a
unique index on the column.
- :unique_constraint_name
-
The name to give the unique key constraint
def column(name, type, opts = OPTS)
columns << {:name => name, :type => type}.merge!(opts)
if index_opts = opts[:index]
index(name, index_opts.is_a?(Hash) ? index_opts : {})
end
nil
end
constraint(name, *args, &block)
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Adds a named constraint (or unnamed if name is nil), with the given block
or args. To provide options for the constraint, pass a hash as the first
argument.
constraint(:blah, num: 1..5)
# CONSTRAINT blah CHECK num >= 1 AND num <= 5
constraint({name: :blah, deferrable: true}, num: 1..5)
# CONSTRAINT blah CHECK num >= 1 AND num <= 5 DEFERRABLE INITIALLY DEFERRED
def constraint(name, *args, &block)
opts = name.is_a?(Hash) ? name : {:name=>name}
constraints << opts.merge(:type=>:check, :check=>block || args)
nil
end
foreign_key(name, table=nil, opts = OPTS)
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Add a foreign key in the table that references another table. 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)
foreign_key(:artist_id, :artists, type: String) # artist_id varchar(255) REFERENCES artists(id)
Additional Options:
- :foreign_key_constraint_name
-
The name to give the foreign key constraint
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
def foreign_key(name, table=nil, opts = OPTS)
opts = case table
when Hash
table.merge(opts)
when NilClass
opts
else
opts.merge(:table=>table)
end
return composite_foreign_key(name, opts) if name.is_a?(Array)
column(name, Integer, opts)
end
full_text_index(columns, opts = OPTS)
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Add a full text index on the given columns.
PostgreSQL specific options:
- :index_type
-
Can be set to :gist to use a GIST index instead of the default GIN index.
- :language
-
Set a language to use for the index (default: simple).
Microsoft SQL Server specific options:
- :key_index
-
The KEY INDEX to use for the full text index.
def full_text_index(columns, opts = OPTS)
index(columns, opts.merge(:type => :full_text))
end
index(columns, opts = OPTS)
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Add an index on the given column(s) with the given options. General
options:
- :name
-
The name to use for the index. If not given, a default name based on the
table and columns is used.
- :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)
PostgreSQL specific options:
- :concurrently
-
Create the index concurrently, so it doesn't block operations on the
table while the index is being built.
- :opclass
-
Use a specific operator class in the index.
Microsoft SQL Server specific options:
- :include
-
Include additional column values in the index, without actually indexing on
those values.
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)
def index(columns, opts = OPTS)
indexes << {:columns => Array(columns)}.merge!(opts)
nil
end
method_missing(type, name = nil, opts = OPTS)
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Add a column with the given type, name, and opts. See column
for available options.
Calls superclass method
def method_missing(type, name = nil, opts = OPTS)
name ? column(name, type, opts) : super
end
primary_key(name, *args)
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Adds an autoincrementing primary key column or a primary key constraint. To
just 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.
If an array of column symbols is used, you can specify the :name option to
name the constraint.
Options:
- :keep_order
-
For non-composite primary keys, respects the existing order of columns,
overriding the default behavior of making the primary key the first column.
Examples:
primary_key(:id)
primary_key(:id, type: :Bignum, keep_order: true)
primary_key([:street_number, :house_number], name: :some constraint_name)
def primary_key(name, *args)
return composite_primary_key(name, *args) if name.is_a?(Array)
column = @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 = opts.merge(:type => type)
end
column.merge!(opts)
end
@primary_key = column
if column[:keep_order]
columns << column
else
columns.unshift(column)
end
nil
end
unique(columns, opts = OPTS)
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Add a unique constraint on the given columns.
unique(:name) # UNIQUE (name)
Supports the same :deferrable option as column. The :name
option can be used to name the constraint.
def unique(columns, opts = OPTS)
constraints << {:type => :unique, :columns => Array(columns)}.merge!(opts)
nil
end