Class: Sequel::Schema::AlterTableGenerator
- 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 “Schema Modification” guide.
Direct Known Subclasses
Instance Attribute Summary collapse
-
#operations ⇒ Object
readonly
An array of DDL operations to perform.
Instance Method Summary collapse
-
#add_column(name, type, opts = {}) ⇒ Object
Add a column with the given name, type, and opts to the DDL for the table.
-
#add_constraint(name, *args, &block) ⇒ Object
Add a constraint with the given name and args to the DDL for the table.
-
#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.
-
#add_full_text_index(columns, opts = {}) ⇒ Object
Add a full text index on the given columns to the DDL for the table.
-
#add_index(columns, opts = {}) ⇒ Object
Add an index on the given columns to the DDL for the table.
-
#add_primary_key(name, opts = {}) ⇒ Object
Add a primary key to the DDL for the table.
-
#add_spatial_index(columns, opts = {}) ⇒ Object
Add a spatial index on the given columns to the DDL for the table.
-
#add_unique_constraint(columns, opts = {}) ⇒ Object
Add a unique constraint to the given column(s).
-
#drop_column(name, opts = {}) ⇒ Object
Remove a column from the DDL for the table.
-
#drop_constraint(name, opts = {}) ⇒ Object
Remove a constraint from the DDL for the table.
-
#drop_foreign_key(name, opts = {}) ⇒ Object
Remove a foreign key and the associated column from the DDL for the table.
-
#drop_index(columns, options = {}) ⇒ Object
Remove an index from the DDL for the table.
-
#initialize(db, &block) ⇒ AlterTableGenerator
constructor
Set the Database object to which to apply the DDL, and evaluate the block in the context of this object.
-
#rename_column(name, new_name, opts = {}) ⇒ Object
Modify a column’s name in the DDL for the table.
-
#set_column_allow_null(name, allow_null = true) ⇒ Object
Set a given column as allowing NULL values.
-
#set_column_default(name, default) ⇒ Object
Modify a column’s default value in the DDL for the table.
-
#set_column_not_null(name) ⇒ Object
Set a given column as not allowing NULL values.
-
#set_column_type(name, type, opts = {}) ⇒ Object
Modify a column’s type in the DDL for the table.
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 301 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 297 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 CreateTableGenerator#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 311 def add_column(name, type, opts = {}) @operations << {:op => :add_column, :name => name, :type => type}.merge(opts) end |
#add_constraint(name, *args, &block) ⇒ Object
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# File 'lib/sequel/database/schema_generator.rb', line 320 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 CreateTableGenerator#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 exist and will only add the constraint. You can provide a :name option to name 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
PostgreSQL specific options:
- :not_valid
-
Set to true to add the constraint with the NOT VALID syntax. This makes it so that future inserts must respect referential integrity, but allows the constraint to be added even if existing column values reference rows that do not exist. After all the existing data has been cleaned up, validate_constraint can be used to mark the constraint as valid. Note that this option only makes sense when using an array of columns.
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# File 'lib/sequel/database/schema_generator.rb', line 356 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 CreateTableGenerator#index for available options.
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# File 'lib/sequel/database/schema_generator.rb', line 363 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 CreateTableGenerator#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 371 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 CreateTableGenerator#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 381 def add_primary_key(name, opts = {}) return add_composite_primary_key(name, opts) if name.is_a?(Array) opts = @db..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 CreateTableGenerator#index for available options.
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# File 'lib/sequel/database/schema_generator.rb', line 389 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)
Supports the same :deferrable option as CreateTableGenerator#column.
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# File 'lib/sequel/database/schema_generator.rb', line 330 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 397 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. MySQL/SQLite specific options:
- :type
-
Set the type of constraint to drop, either :primary_key, :foreign_key, or :unique.
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 408 def drop_constraint(name, opts={}) @operations << {:op => :drop_constraint, :name => name}.merge(opts) end |
#drop_foreign_key(name, opts = {}) ⇒ Object
Remove a foreign key and the associated column from the DDL for the table. General options:
- :name
-
The name of the constraint to drop. If not given, uses the same name that would be used by add_foreign_key with the same columns.
NOTE: If you want to drop only the foreign key constraint but keep the column, use the composite key syntax even if it is only one column.
drop_foreign_key(:artist_id) # DROP CONSTRAINT table_artist_id_fkey, DROP COLUMN artist_id
drop_foreign_key([:name]) # DROP CONSTRAINT table_name_fkey
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# File 'lib/sequel/database/schema_generator.rb', line 422 def drop_foreign_key(name, opts={}) drop_composite_foreign_key(Array(name), opts) drop_column(name) unless name.is_a?(Array) end |
#drop_index(columns, options = {}) ⇒ Object
Remove an index from the DDL for the table. General options:
- :name
-
The name of the index to drop. If not given, uses the same name that would be used by add_index with the same columns.
PostgreSQL specific options:
- :cascade
-
Cascade the index drop to dependent objects.
- :concurrently
-
Drop the index using CONCURRENTLY, which doesn’t block operations on the table. Supported in PostgreSQL 9.2+.
- :if_exists
-
Only drop the index if it already exists.
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 442 def drop_index(columns, ={}) @operations << {:op => :drop_index, :columns => Array(columns)}.merge() 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 449 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 = true) ⇒ Object
Set a given column as allowing NULL values.
set_column_allow_null(:artist_name) # ALTER COLUMN artist_name DROP NOT NULL
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# File 'lib/sequel/database/schema_generator.rb', line 474 def set_column_allow_null(name, allow_null=true) @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 456 def set_column_default(name, default) @operations << {:op => :set_column_default, :name => name, :default => default} end |
#set_column_not_null(name) ⇒ Object
Set a given column as not allowing NULL values.
set_column_not_null(:artist_name) # ALTER COLUMN artist_name SET NOT NULL
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# File 'lib/sequel/database/schema_generator.rb', line 481 def set_column_not_null(name) set_column_allow_null(name, false) 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)
PostgreSQL specific options:
- :using
-
Add a USING clause that specifies how to convert existing values to new values.
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# File 'lib/sequel/database/schema_generator.rb', line 467 def set_column_type(name, type, opts={}) @operations << {:op => :set_column_type, :name => name, :type => type}.merge(opts) end |