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 operations to perform.
Instance Method Summary collapse
-
#add_column(name, type, opts = OPTS) ⇒ Object
Add a column with the given name, type, and opts.
-
#add_constraint(name, *args, &block) ⇒ Object
Add a constraint with the given name and args.
-
#add_foreign_key(name, table, opts = OPTS) ⇒ Object
Add a foreign key with the given name and referencing the given table.
-
#add_full_text_index(columns, opts = OPTS) ⇒ Object
Add a full text index on the given columns.
-
#add_index(columns, opts = OPTS) ⇒ Object
Add an index on the given columns.
-
#add_primary_key(name, opts = OPTS) ⇒ Object
Add a primary key.
-
#add_spatial_index(columns, opts = OPTS) ⇒ Object
Add a spatial index on the given columns.
-
#add_unique_constraint(columns, opts = OPTS) ⇒ Object
Add a unique constraint to the given column(s).
-
#drop_column(name, opts = OPTS) ⇒ Object
Remove a column from the table.
-
#drop_constraint(name, opts = OPTS) ⇒ Object
Remove a constraint from the table:.
-
#drop_foreign_key(name, opts = OPTS) ⇒ Object
Remove a foreign key and the associated column from the table.
-
#drop_index(columns, options = OPTS) ⇒ Object
Remove an index from the table.
-
#initialize(db, &block) ⇒ AlterTableGenerator
constructor
Set the Database object to which to apply the changes, and evaluate the block in the context of this object.
-
#rename_column(name, new_name, opts = OPTS) ⇒ Object
Rename one of the table's columns.
-
#set_column_allow_null(name, allow_null = true) ⇒ Object
Set a given column as allowing NULL values.
-
#set_column_default(name, default) ⇒ Object
Modify the default value for one of the table's column.
-
#set_column_not_null(name) ⇒ Object
Set a given column as not allowing NULL values.
-
#set_column_type(name, type, opts = OPTS) ⇒ Object
Modify the type of one of the table's column.
Constructor Details
#initialize(db, &block) ⇒ AlterTableGenerator
Set the Database object to which to apply the changes, and evaluate the block in the context of this object.
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# File 'lib/sequel/database/schema_generator.rb', line 361 def initialize(db, &block) @db = db @operations = [] instance_exec(&block) if block end |
Instance Attribute Details
#operations ⇒ Object (readonly)
An array of operations to perform
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# File 'lib/sequel/database/schema_generator.rb', line 357 def operations @operations end |
Instance Method Details
#add_column(name, type, opts = OPTS) ⇒ Object
Add a column with the given name, type, and opts. See CreateTableGenerator#column for the available options (except for :index
, use a separate add_index
call to add an index for the column).
add_column(:name, String) # ADD COLUMN name varchar(255)
PostgreSQL specific options:
- :if_not_exists
-
Set to true to not add the column if it already exists (PostgreSQL 9.6+)
MySQL specific options:
- :after
-
The name of an existing column that the new column should be positioned after
- :first
-
Create this new column before all other existing columns
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# File 'lib/sequel/database/schema_generator.rb', line 381 def add_column(name, type, opts = OPTS) @operations << {:op => :add_column, :name => name, :type => type}.merge!(opts) nil end |
#add_constraint(name, *args, &block) ⇒ Object
Add a constraint with the given name and args. See CreateTableGenerator#constraint.
add_constraint(:valid_name, Sequel.like(:name, 'A%'))
# ADD CONSTRAINT valid_name CHECK (name LIKE 'A%' ESCAPE '\')
add_constraint({name: :valid_name, deferrable: true}, Sequel.like(:name, 'A%'))
# ADD CONSTRAINT valid_name CHECK (name LIKE 'A%' ESCAPE '\') DEFERRABLE INITIALLY DEFERRED
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# File 'lib/sequel/database/schema_generator.rb', line 393 def add_constraint(name, *args, &block) opts = name.is_a?(Hash) ? name : {:name=>name} @operations << opts.merge(:op=>:add_constraint, :type=>:check, :check=>block || args) nil end |
#add_foreign_key(name, table, opts = OPTS) ⇒ Object
Add a foreign key with the given name and referencing the given table. See CreateTableGenerator#column for the available options (except for :index
, use a separate add_index
call to add an index for the column).
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 433 def add_foreign_key(name, table, opts = 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 = OPTS) ⇒ Object
Add a full text index on the given columns. See CreateTableGenerator#index for available options.
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# File 'lib/sequel/database/schema_generator.rb', line 440 def add_full_text_index(columns, opts = OPTS) add_index(columns, {:type=>:full_text}.merge!(opts)) end |
#add_index(columns, opts = OPTS) ⇒ Object
Add an index on the given columns. See CreateTableGenerator#index for available options.
add_index(:artist_id) # CREATE INDEX table_artist_id_index ON table (artist_id)
Options:
- :name
-
Give a specific name for the index. Highly recommended if you plan on dropping the index later.
- :where
-
A filter expression, used to setup a partial index (if supported).
- :unique
-
Create a unique index.
PostgreSQL specific options:
- :concurrently
-
Create the index concurrently, so it doesn't require an exclusive lock on the table.
- :index_type
-
The underlying index type to use for a full_text index, gin by default).
- :language
-
The language to use for a full text index (simple by default).
- :opclass
-
Set an opclass to use for all columns (per-column opclasses require custom SQL).
- :type
-
Set the index type (e.g. full_text, spatial, hash, gin, gist, btree).
- :if_not_exists
-
Only create the index if an index of the same name doesn't already exists
MySQL specific options:
- :type
-
Set the index type, with full_text and spatial indexes handled specially.
Microsoft SQL Server specific options:
- :include
-
Includes additional columns in the index.
- :key_index
-
Sets the KEY INDEX to the given value.
- :type
-
clustered uses a clustered index, full_text uses a full text index.
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# File 'lib/sequel/database/schema_generator.rb', line 476 def add_index(columns, opts = OPTS) @operations << {:op => :add_index, :columns => Array(columns)}.merge!(opts) nil end |
#add_primary_key(name, opts = OPTS) ⇒ Object
Add a primary key. 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 487 def add_primary_key(name, opts = 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 = OPTS) ⇒ Object
Add a spatial index on the given columns. See CreateTableGenerator#index for available options.
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# File 'lib/sequel/database/schema_generator.rb', line 495 def add_spatial_index(columns, opts = OPTS) add_index(columns, {:type=>:spatial}.merge!(opts)) end |
#add_unique_constraint(columns, opts = 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 405 def add_unique_constraint(columns, opts = OPTS) @operations << {:op => :add_constraint, :type => :unique, :columns => Array(columns)}.merge!(opts) nil end |
#drop_column(name, opts = OPTS) ⇒ Object
Remove a column from the table.
drop_column(:artist_id) # DROP COLUMN artist_id
drop_column(:artist_id, cascade: true) # DROP COLUMN artist_id CASCADE
Options:
- :cascade
-
CASCADE the operation, dropping other objects that depend on the dropped column.
PostgreSQL specific options:
- :if_exists
-
Use IF EXISTS, so no error is raised if the column does not exist.
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# File 'lib/sequel/database/schema_generator.rb', line 512 def drop_column(name, opts=OPTS) @operations << {:op => :drop_column, :name => name}.merge!(opts) nil end |
#drop_constraint(name, opts = OPTS) ⇒ Object
Remove a constraint from the table:
drop_constraint(:unique_name) # DROP CONSTRAINT unique_name
drop_constraint(:unique_name, cascade: true) # DROP CONSTRAINT unique_name CASCADE
MySQL/SQLite specific options:
- :type
-
Set the type of constraint to drop, either :primary_key, :foreign_key, or :unique.
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# File 'lib/sequel/database/schema_generator.rb', line 526 def drop_constraint(name, opts=OPTS) @operations << {:op => :drop_constraint, :name => name}.merge!(opts) nil end |
#drop_foreign_key(name, opts = OPTS) ⇒ Object
Remove a foreign key and the associated column from 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 541 def drop_foreign_key(name, opts=OPTS) if !name.is_a?(Array) && opts[:foreign_key_constraint_name] opts = Hash[opts] opts[:name] = opts[:foreign_key_constraint_name] end drop_composite_foreign_key(Array(name), opts) drop_column(name) unless name.is_a?(Array) end |
#drop_index(columns, options = OPTS) ⇒ Object
Remove an index from 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 565 def drop_index(columns, =OPTS) @operations << {:op => :drop_index, :columns => Array(columns)}.merge!() nil end |
#rename_column(name, new_name, opts = OPTS) ⇒ Object
Rename one of the table's columns.
rename_column(:name, :artist_name) # RENAME COLUMN name TO artist_name
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# File 'lib/sequel/database/schema_generator.rb', line 573 def rename_column(name, new_name, opts = OPTS) @operations << {:op => :rename_column, :name => name, :new_name => new_name}.merge!(opts) nil 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
On MySQL, make sure to use a symbol for the name of the column, as otherwise you can lose the default and type for the column.
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# File 'lib/sequel/database/schema_generator.rb', line 614 def set_column_allow_null(name, allow_null=true) @operations << {:op => :set_column_null, :name => name, :null => allow_null} nil end |
#set_column_default(name, default) ⇒ Object
Modify the default value for one of the table's column.
set_column_default(:artist_name, 'a') # ALTER COLUMN artist_name SET DEFAULT 'a'
To remove an existing default value, use nil
as the value:
set_column_default(:artist_name, nil) # ALTER COLUMN artist_name SET DEFAULT NULL
On MySQL, make sure to use a symbol for the name of the column, as otherwise you can lose the type and NULL/NOT NULL setting for the column.
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# File 'lib/sequel/database/schema_generator.rb', line 588 def set_column_default(name, default) @operations << {:op => :set_column_default, :name => name, :default => default} nil 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
On MySQL, make sure to use a symbol for the name of the column, as otherwise you can lose the default and type for the column.
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# File 'lib/sequel/database/schema_generator.rb', line 625 def set_column_not_null(name) set_column_allow_null(name, false) end |
#set_column_type(name, type, opts = OPTS) ⇒ Object
Modify the type of one of the table's column.
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.
On MySQL, make sure to use a symbol for the name of the column, as otherwise you can lose the default and NULL/NOT NULL setting for the column.
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# File 'lib/sequel/database/schema_generator.rb', line 603 def set_column_type(name, type, opts=OPTS) @operations << {:op => :set_column_type, :name => name, :type => type}.merge!(opts) nil end |