Module | ActiveRecord::ConnectionAdapters::SchemaStatements |
In: |
vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
|
Adds a new column to the named table. See TableDefinition#column for details of the options you can use.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 186 186: def add_column(table_name, column_name, type, options = {}) 187: add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}" 188: add_column_options!(add_column_sql, options) 189: execute(add_column_sql) 190: end
Adds a new index to the table. column_name can be a single Symbol, or an Array of Symbols.
The index will be named after the table and the first column name, unless you pass :name as an option.
When creating an index on multiple columns, the first column is used as a name for the index. For example, when you specify an index on two columns [:first, :last], the DBMS creates an index for both columns as well as an index for the first column :first. Using just the first name for this index makes sense, because you will never have to create a singular index with this name.
add_index(:suppliers, :name)
generates
CREATE INDEX suppliers_name_index ON suppliers(name)
add_index(:accounts, [:branch_id, :party_id], :unique => true)
generates
CREATE UNIQUE INDEX accounts_branch_id_party_id_index ON accounts(branch_id, party_id)
add_index(:accounts, [:branch_id, :party_id], :unique => true, :name => 'by_branch_party')
generates
CREATE UNIQUE INDEX by_branch_party ON accounts(branch_id, party_id)
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 255 255: def add_index(table_name, column_name, options = {}) 256: column_names = Array(column_name) 257: index_name = index_name(table_name, :column => column_names) 258: 259: if Hash === options # legacy support, since this param was a string 260: index_type = options[:unique] ? "UNIQUE" : "" 261: index_name = options[:name] || index_name 262: else 263: index_type = options 264: end 265: quoted_column_names = column_names.map { |e| quote_column_name(e) }.join(", ") 266: execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{quoted_column_names})" 267: end
ORDER BY clause for the passed order option. PostgreSQL overrides this due to its stricter standards compliance.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 395 395: def add_order_by_for_association_limiting!(sql, options) 396: sql << " ORDER BY #{options[:order]}" 397: end
Adds timestamps (created_at and updated_at) columns to the named table.
add_timestamps(:suppliers)
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 402 402: def add_timestamps(table_name) 403: add_column table_name, :created_at, :datetime 404: add_column table_name, :updated_at, :datetime 405: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 333 333: def assume_migrated_upto_version(version) 334: sm_table = quote_table_name(ActiveRecord::Migrator.schema_migrations_table_name) 335: migrated = select_values("SELECT version FROM #{sm_table}").map(&:to_i) 336: versions = Dir['db/migrate/[0-9]*_*.rb'].map do |filename| 337: filename.split('/').last.split('_').first.to_i 338: end 339: 340: execute "INSERT INTO #{sm_table} (version) VALUES ('#{version}')" unless migrated.include?(version.to_i) 341: (versions - migrated).select { |v| v < version.to_i }.each do |v| 342: execute "INSERT INTO #{sm_table} (version) VALUES ('#{v}')" 343: end 344: end
Changes the column‘s definition according to the new options. See TableDefinition#column for details of the options you can use.
change_column(:suppliers, :name, :string, :limit => 80) change_column(:accounts, :description, :text)
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 208 208: def change_column(table_name, column_name, type, options = {}) 209: raise NotImplementedError, "change_column is not implemented" 210: end
Sets a new default value for a column. If you want to set the default value to NULL, you are out of luck. You need to DatabaseStatements#execute the appropriate SQL statement yourself.
change_column_default(:suppliers, :qualification, 'new') change_column_default(:accounts, :authorized, 1)
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 218 218: def change_column_default(table_name, column_name, default) 219: raise NotImplementedError, "change_column_default is not implemented" 220: end
A block for changing columns in table.
# change_table() yields a Table instance change_table(:suppliers) do |t| t.column :name, :string, :limit => 60 # Other column alterations here end
change_table(:suppliers) do |t| t.column :name, :string, :limit => 60 end
change_table(:suppliers) do |t| t.integer :width, :height, :null => false, :default => 0 end
change_table(:suppliers) do |t| t.timestamps end
change_table(:suppliers) do |t| t.references :company end
Creates a company_id(integer) column
change_table(:suppliers) do |t| t.belongs_to :company, :polymorphic => true end
Creates company_type(varchar) and company_id(integer) columns
change_table(:suppliers) do |t| t.remove :company end
change_table(:suppliers) do |t| t.remove :company_id t.remove :width, :height end
change_table(:suppliers) do |t| t.remove_index :company_id end
See also Table for details on all of the various column transformation
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 168 168: def change_table(table_name) 169: yield Table.new(table_name, self) 170: end
Returns an array of Column objects for the table specified by table_name. See the concrete implementation for details on the expected parameter values.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 32 32: def columns(table_name, name = nil) end
Creates a new table There are two ways to work with create_table. You can use the block form or the regular form, like this:
# create_table() yields a TableDefinition instance create_table(:suppliers) do |t| t.column :name, :string, :limit => 60 # Other fields here end
create_table(:suppliers) add_column(:suppliers, :name, :string, {:limit => 60})
The options hash can include the following keys:
create_table(:suppliers, :options => 'ENGINE=InnoDB DEFAULT CHARSET=utf8')
generates:
CREATE TABLE suppliers ( id int(11) DEFAULT NULL auto_increment PRIMARY KEY ) ENGINE=InnoDB DEFAULT CHARSET=utf8
create_table(:objects, :primary_key => 'guid') do |t| t.column :name, :string, :limit => 80 end
generates:
CREATE TABLE objects ( guid int(11) DEFAULT NULL auto_increment PRIMARY KEY, name varchar(80) )
create_table(:categories_suppliers, :id => false) do |t| t.column :category_id, :integer t.column :supplier_id, :integer end
generates:
CREATE TABLE categories_suppliers ( category_id int, supplier_id int )
See also TableDefinition#column for details on how to create columns.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 94 94: def create_table(table_name, options = {}) 95: table_definition = TableDefinition.new(self) 96: table_definition.primary_key(options[:primary_key] || Base.get_primary_key(table_name)) unless options[:id] == false 97: 98: yield table_definition 99: 100: if options[:force] && table_exists?(table_name) 101: drop_table(table_name, options) 102: end 103: 104: create_sql = "CREATE#{' TEMPORARY' if options[:temporary]} TABLE " 105: create_sql << "#{quote_table_name(table_name)} (" 106: create_sql << table_definition.to_sql 107: create_sql << ") #{options[:options]}" 108: execute create_sql 109: end
SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause. Both PostgreSQL and Oracle overrides this for custom DISTINCT syntax.
distinct("posts.id", "posts.created_at desc")
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 389 389: def distinct(columns, order_by) 390: "DISTINCT #{columns}" 391: end
Drops a table from the database.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 180 180: def drop_table(table_name, options = {}) 181: execute "DROP TABLE #{quote_table_name(table_name)}" 182: end
Should not be called normally, but this operation is non-destructive. The migrations module handles this automatically.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 310 310: def initialize_schema_migrations_table 311: sm_table = ActiveRecord::Migrator.schema_migrations_table_name 312: 313: unless tables.detect { |t| t == sm_table } 314: create_table(sm_table, :id => false) do |schema_migrations_table| 315: schema_migrations_table.column :version, :string, :null => false 316: end 317: add_index sm_table, :version, :unique => true, 318: :name => 'unique_schema_migrations' 319: 320: # Backwards-compatibility: if we find schema_info, assume we've 321: # migrated up to that point: 322: si_table = Base.table_name_prefix + 'schema_info' + Base.table_name_suffix 323: 324: if tables.detect { |t| t == si_table } 325: 326: old_version = select_value("SELECT version FROM #{quote_table_name(si_table)}").to_i 327: assume_migrated_upto_version(old_version) 328: drop_table(si_table) 329: end 330: end 331: end
Returns a Hash of mappings from the abstract data types to the native database types. See TableDefinition#column for details on the recognized abstract data types.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 7 7: def native_database_types 8: {} 9: end
Removes the column(s) from the table definition.
remove_column(:suppliers, :qualification) remove_columns(:suppliers, :qualification, :experience)
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 196 196: def remove_column(table_name, *column_names) 197: column_names.flatten.each do |column_name| 198: execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{quote_column_name(column_name)}" 199: end 200: end
Remove the given index from the table.
Remove the suppliers_name_index in the suppliers table.
remove_index :suppliers, :name
Remove the index named accounts_branch_id_index in the accounts table.
remove_index :accounts, :column => :branch_id
Remove the index named accounts_branch_id_party_id_index in the accounts table.
remove_index :accounts, :column => [:branch_id, :party_id]
Remove the index named by_branch_party in the accounts table.
remove_index :accounts, :name => :by_branch_party
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 279 279: def remove_index(table_name, options = {}) 280: execute "DROP INDEX #{quote_column_name(index_name(table_name, options))} ON #{table_name}" 281: end
Removes the timestamp columns (created_at and updated_at) from the table definition.
remove_timestamps(:suppliers)
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 410 410: def remove_timestamps(table_name) 411: remove_column table_name, :updated_at 412: remove_column table_name, :created_at 413: end
Renames a column.
rename_column(:suppliers, :description, :name)
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 225 225: def rename_column(table_name, column_name, new_column_name) 226: raise NotImplementedError, "rename_column is not implemented" 227: end
Renames a table.
rename_table('octopuses', 'octopi')
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 175 175: def rename_table(table_name, new_name) 176: raise NotImplementedError, "rename_table is not implemented" 177: end
Returns a string of CREATE TABLE SQL statement(s) for recreating the entire structure of the database.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 299 299: def structure_dump 300: end
Truncates a table alias according to the limits of the current adapter.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 17 17: def table_alias_for(table_name) 18: table_name[0..table_alias_length-1].gsub(/\./, '_') 19: end
This is the maximum length a table alias can be
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 12 12: def table_alias_length 13: 255 14: end
def tables(name = nil) end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 23 23: def table_exists?(table_name) 24: tables.include?(table_name.to_s) 25: end