Class: Sequel::Schema::AlterTableGenerator

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

Overview

Schema::AlterTableGenerator is an internal class that the user is not expected to instantiate directly. Instances are created by Database#alter_table. It is used to specify table alteration parameters. It takes a Database object and a block of operations to perform on the table, and gives the Database an array of table altering operations, which the database uses to alter a table’s description.

For more information on Sequel’s support for schema modification, see the “Migrations and Schema Modification” guide.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(db, &block) ⇒ AlterTableGenerator

Set the Database object to which to apply the DDL, and evaluate the block in the context of this object.



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# File 'lib/sequel/database/schema_generator.rb', line 249

def initialize(db, &block)
  @db = db
  @operations = []
  instance_eval(&block) if block
end

Instance Attribute Details

#operations ⇒ Object (readonly)

An array of DDL operations to perform



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# File 'lib/sequel/database/schema_generator.rb', line 245

def operations
  @operations
end

Instance Method Details

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

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

add_column(:name, String) # ADD COLUMN name varchar(255)



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# File 'lib/sequel/database/schema_generator.rb', line 259

def add_column(name, type, opts = {})
  @operations << {:op => :add_column, :name => name, :type => type}.merge(opts)
end

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

Add a constraint with the given name and args to the DDL for the table. See Generator#constraint.

add_constraint(:valid_name, :name.like('A%'))
# ADD CONSTRAINT valid_name CHECK (name LIKE 'A%')



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# File 'lib/sequel/database/schema_generator.rb', line 268

def add_constraint(name, *args, &block)
  @operations << {:op => :add_constraint, :name => name, :type => :check, :check => block || args}
end

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

Add a foreign key with the given name and referencing the given table to the DDL for the table. See Generator#column for the available options.

You can also pass an array of column names for creating composite foreign keys. In this case, it will assume the columns exists and will only add the constraint.

NOTE: If you need to add a foreign key constraint to a single existing column use the composite key syntax even if it is only one column.

add_foreign_key(:artist_id, :table) # ADD COLUMN artist_id integer REFERENCES table
add_foreign_key([:name], :table) # ADD FOREIGN KEY (name) REFERENCES table



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# File 'lib/sequel/database/schema_generator.rb', line 292

def add_foreign_key(name, table, opts = {})
  return add_composite_foreign_key(name, table, opts) if name.is_a?(Array)
  add_column(name, Integer, {:table=>table}.merge(opts))
end

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

Add a full text index on the given columns to the DDL for the table. See Generator#index for available options.



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# File 'lib/sequel/database/schema_generator.rb', line 299

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

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

Add an index on the given columns to the DDL for the table. See Generator#index for available options.

add_index(:artist_id) # CREATE INDEX table_artist_id_index ON table (artist_id)



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# File 'lib/sequel/database/schema_generator.rb', line 307

def add_index(columns, opts = {})
  @operations << {:op => :add_index, :columns => Array(columns)}.merge(opts)
end

#add_primary_key(name, opts = {}) ⇒ Object

Add a primary key to the DDL for the table. See Generator#column for the available options. Like add_foreign_key, if you specify the column name as an array, it just creates a constraint:

add_primary_key(:id) # ADD COLUMN id serial PRIMARY KEY
add_primary_key([:artist_id, :name]) # ADD PRIMARY KEY (artist_id, name)



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# File 'lib/sequel/database/schema_generator.rb', line 317

def add_primary_key(name, opts = {})
  return add_composite_primary_key(name, opts) if name.is_a?(Array)
  opts = @db.serial_primary_key_options.merge(opts)
  add_column(name, opts.delete(:type), opts)
end

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

Add a spatial index on the given columns to the DDL for the table. See Generator#index for available options.



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# File 'lib/sequel/database/schema_generator.rb', line 325

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

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

Add a unique constraint to the given column(s)

add_unique_constraint(:name) # ADD UNIQUE (name)
add_unique_constraint(:name, :name=>:unique_name) # ADD CONSTRAINT unique_name UNIQUE (name)



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# File 'lib/sequel/database/schema_generator.rb', line 276

def add_unique_constraint(columns, opts = {})
  @operations << {:op => :add_constraint, :type => :unique, :columns => Array(columns)}.merge(opts)
end

#drop_column(name, opts = {}) ⇒ Object

Remove a column from the DDL for the table.

drop_column(:artist_id) # DROP COLUMN artist_id
drop_column(:artist_id, :cascade=>true) # DROP COLUMN artist_id CASCADE



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# File 'lib/sequel/database/schema_generator.rb', line 333

def drop_column(name, opts={})
  @operations << {:op => :drop_column, :name => name}.merge(opts)
end

#drop_constraint(name, opts = {}) ⇒ Object

Remove a constraint from the DDL for the table.

drop_constraint(:unique_name) # DROP CONSTRAINT unique_name
drop_constraint(:unique_name, :cascade=>true) # DROP CONSTRAINT unique_name CASCADE



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# File 'lib/sequel/database/schema_generator.rb', line 341

def drop_constraint(name, opts={})
  @operations << {:op => :drop_constraint, :name => name}.merge(opts)
end

#drop_index(columns, options = {}) ⇒ Object

Remove an index from the DDL for the table.

drop_index(:artist_id) # DROP INDEX table_artist_id_index
drop_index([:a, :b]) # DROP INDEX table_a_b_index
drop_index([:a, :b], :name=>:foo) # DROP INDEX foo



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# File 'lib/sequel/database/schema_generator.rb', line 350

def drop_index(columns, options={})
  @operations << {:op => :drop_index, :columns => Array(columns)}.merge(options)
end

#rename_column(name, new_name, opts = {}) ⇒ Object

Modify a column’s name in the DDL for the table.

rename_column(:name, :artist_name) # RENAME COLUMN name TO artist_name



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# File 'lib/sequel/database/schema_generator.rb', line 357

def rename_column(name, new_name, opts = {})
  @operations << {:op => :rename_column, :name => name, :new_name => new_name}.merge(opts)
end

#set_column_allow_null(name, allow_null) ⇒ Object

Modify a column’s NOT NULL constraint.

set_column_allow_null(:artist_name, false) # ALTER COLUMN artist_name SET NOT NULL



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# File 'lib/sequel/database/schema_generator.rb', line 378

def set_column_allow_null(name, allow_null)
  @operations << {:op => :set_column_null, :name => name, :null => allow_null}
end

#set_column_default(name, default) ⇒ Object

Modify a column’s default value in the DDL for the table.

set_column_default(:artist_name, 'a') # ALTER COLUMN artist_name SET DEFAULT 'a'



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# File 'lib/sequel/database/schema_generator.rb', line 364

def set_column_default(name, default)
  @operations << {:op => :set_column_default, :name => name, :default => default}
end

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

Modify a column’s type in the DDL for the table.

set_column_type(:artist_name, 'char(10)') # ALTER COLUMN artist_name TYPE char(10)



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# File 'lib/sequel/database/schema_generator.rb', line 371

def set_column_type(name, type, opts={})
  @operations << {:op => :set_column_type, :name => name, :type => type}.merge(opts)
end