W3cubDocs

/Ruby on Rails 5.2

module ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

Public Instance Methods

bulk_change_table(table_name, operations) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 371
def bulk_change_table(table_name, operations)
  sql_fragments = []
  non_combinable_operations = []

  operations.each do |command, args|
    table, arguments = args.shift, args
    method = :"#{command}_for_alter"

    if respond_to?(method, true)
      sqls, procs = Array(send(method, table, *arguments)).partition { |v| v.is_a?(String) }
      sql_fragments << sqls
      non_combinable_operations.concat(procs)
    else
      execute "ALTER TABLE #{quote_table_name(table_name)} #{sql_fragments.join(", ")}" unless sql_fragments.empty?
      non_combinable_operations.each(&:call)
      sql_fragments = []
      non_combinable_operations = []
      send(command, table, *arguments)
    end
  end

  execute "ALTER TABLE #{quote_table_name(table_name)} #{sql_fragments.join(", ")}" unless sql_fragments.empty?
  non_combinable_operations.each(&:call)
end
client_min_messages() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 236
def client_min_messages
  query_value("SHOW client_min_messages", "SCHEMA")
end

Returns the current client message level.

client_min_messages=(level) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 241
def client_min_messages=(level)
  execute("SET client_min_messages TO '#{level}'", "SCHEMA")
end

Set the client message level.

collation() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 188
def collation
  query_value("SELECT datcollate FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

Returns the current database collation.

create_database(name, options = {}) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 22
def create_database(name, options = {})
  options = { encoding: "utf8" }.merge!(options.symbolize_keys)

  option_string = options.inject("") do |memo, (key, value)|
    memo += case key
            when :owner
              " OWNER = \"#{value}\""
            when :template
              " TEMPLATE = \"#{value}\""
            when :encoding
              " ENCODING = '#{value}'"
            when :collation
              " LC_COLLATE = '#{value}'"
            when :ctype
              " LC_CTYPE = '#{value}'"
            when :tablespace
              " TABLESPACE = \"#{value}\""
            when :connection_limit
              " CONNECTION LIMIT = #{value}"
            else
              ""
    end
  end

  execute "CREATE DATABASE #{quote_table_name(name)}#{option_string}"
end

Create a new PostgreSQL database. Options include :owner, :template, :encoding (defaults to utf8), :collation, :ctype, :tablespace, and :connection_limit (note that MySQL uses :charset while PostgreSQL uses :encoding).

Example:

create_database config[:database], config
create_database 'foo_development', encoding: 'unicode'
create_schema(schema_name) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 209
def create_schema(schema_name)
  execute "CREATE SCHEMA #{quote_schema_name(schema_name)}"
end

Creates a schema for the given schema name.

ctype() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 193
def ctype
  query_value("SELECT datctype FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

Returns the current database ctype.

current_database() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 173
def current_database
  query_value("SELECT current_database()", "SCHEMA")
end

Returns the current database name.

current_schema() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 178
def current_schema
  query_value("SELECT current_schema", "SCHEMA")
end

Returns the current schema name.

drop_schema(schema_name, options = {}) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 214
def drop_schema(schema_name, options = {})
  execute "DROP SCHEMA#{' IF EXISTS' if options[:if_exists]} #{quote_schema_name(schema_name)} CASCADE"
end

Drops the schema for the given schema name.

encoding() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 183
def encoding
  query_value("SELECT pg_encoding_to_char(encoding) FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

Returns the current database encoding format.

foreign_keys(table_name) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 503
        def foreign_keys(table_name)
          scope = quoted_scope(table_name)
          fk_info = exec_query(<<-SQL.strip_heredoc, "SCHEMA")
            SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete, c.convalidated AS valid
            FROM pg_constraint c
            JOIN pg_class t1 ON c.conrelid = t1.oid
            JOIN pg_class t2 ON c.confrelid = t2.oid
            JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
            JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
            JOIN pg_namespace t3 ON c.connamespace = t3.oid
            WHERE c.contype = 'f'
              AND t1.relname = #{scope[:name]}
              AND t3.nspname = #{scope[:schema]}
            ORDER BY c.conname
          SQL

          fk_info.map do |row|
            options = {
              column: row["column"],
              name: row["name"],
              primary_key: row["primary_key"]
            }

            options[:on_delete] = extract_foreign_key_action(row["on_delete"])
            options[:on_update] = extract_foreign_key_action(row["on_update"])
            options[:validate] = row["valid"]

            ForeignKeyDefinition.new(table_name, row["to_table"], options)
          end
        end
foreign_table_exists?(table_name) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 538
def foreign_table_exists?(table_name)
  query_values(data_source_sql(table_name, type: "FOREIGN TABLE"), "SCHEMA").any? if table_name.present?
end
foreign_tables() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 534
def foreign_tables
  query_values(data_source_sql(type: "FOREIGN TABLE"), "SCHEMA")
end
index_name_exists?(table_name, index_name) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 67
        def index_name_exists?(table_name, index_name)
          table = quoted_scope(table_name)
          index = quoted_scope(index_name)

          query_value(<<-SQL, "SCHEMA").to_i > 0
            SELECT COUNT(*)
            FROM pg_class t
            INNER JOIN pg_index d ON t.oid = d.indrelid
            INNER JOIN pg_class i ON d.indexrelid = i.oid
            LEFT JOIN pg_namespace n ON n.oid = i.relnamespace
            WHERE i.relkind = 'i'
              AND i.relname = #{index[:name]}
              AND t.relname = #{table[:name]}
              AND n.nspname = #{index[:schema]}
          SQL
        end

Verifies existence of an index with a given name.

rename_index(table_name, old_name, new_name) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 497
def rename_index(table_name, old_name, new_name)
  validate_index_length!(table_name, new_name)

  execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
end

Renames an index of a table. Raises error if length of new index name is greater than allowed limit.

rename_table(table_name, new_name) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 402
def rename_table(table_name, new_name)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
  pk, seq = pk_and_sequence_for(new_name)
  if pk
    idx = "#{table_name}_pkey"
    new_idx = "#{new_name}_pkey"
    execute "ALTER INDEX #{quote_table_name(idx)} RENAME TO #{quote_table_name(new_idx)}"
    if seq && seq.identifier == "#{table_name}_#{pk}_seq"
      new_seq = "#{new_name}_#{pk}_seq"
      execute "ALTER TABLE #{seq.quoted} RENAME TO #{quote_table_name(new_seq)}"
    end
  end
  rename_table_indexes(table_name, new_name)
end

Renames a table. Also renames a table's primary key sequence if the sequence name exists and matches the Active Record default.

Example:

rename_table('octopuses', 'octopi')
schema_exists?(name) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 62
def schema_exists?(name)
  query_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = #{quote(name)}", "SCHEMA").to_i > 0
end

Returns true if schema exists.

schema_names() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 198
        def schema_names
          query_values(<<-SQL, "SCHEMA")
            SELECT nspname
              FROM pg_namespace
             WHERE nspname !~ '^pg_.*'
               AND nspname NOT IN ('information_schema')
             ORDER by nspname;
          SQL
        end

Returns an array of schema names.

schema_search_path() Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 231
def schema_search_path
  @schema_search_path ||= query_value("SHOW search_path", "SCHEMA")
end

Returns the active schema search path.

schema_search_path=(schema_csv) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 223
def schema_search_path=(schema_csv)
  if schema_csv
    execute("SET search_path TO #{schema_csv}", "SCHEMA")
    @schema_search_path = schema_csv
  end
end

Sets the schema search path to a string of comma-separated schema names. Names beginning with $ have to be quoted (e.g. $user => '$user'). See: www.postgresql.org/docs/current/static/ddl-schemas.html

This should be not be called manually but set in database.yml.

serial_sequence(table, column) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 254
def serial_sequence(table, column)
  query_value("SELECT pg_get_serial_sequence(#{quote(table)}, #{quote(column)})", "SCHEMA")
end
validate_constraint(table_name, constraint_name) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 602
def validate_constraint(table_name, constraint_name)
  return unless supports_validate_constraints?

  at = create_alter_table table_name
  at.validate_constraint constraint_name

  execute schema_creation.accept(at)
end

Validates the given constraint.

Validates the constraint named constraint_name on accounts.

validate_constraint :accounts, :constraint_name
validate_foreign_key(from_table, options_or_to_table = {}) Show source
# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 626
def validate_foreign_key(from_table, options_or_to_table = {})
  return unless supports_validate_constraints?

  fk_name_to_validate = foreign_key_for!(from_table, options_or_to_table).name

  validate_constraint from_table, fk_name_to_validate
end

Validates the given foreign key.

Validates the foreign key on accounts.branch_id.

validate_foreign_key :accounts, :branches

Validates the foreign key on accounts.owner_id.

validate_foreign_key :accounts, column: :owner_id

Validates the foreign key named special_fk_name on the accounts table.

validate_foreign_key :accounts, name: :special_fk_name

The options hash accepts the same keys as SchemaStatements#add_foreign_key.

© 2004–2018 David Heinemeier Hansson
Licensed under the MIT License.