Module: ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 296

def client_min_messages=(level)
  internal_execute("SET client_min_messages TO '#{level}'", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 286

def schema_search_path
  @schema_search_path ||= query_value("SHOW search_path", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 278

def schema_search_path=(schema_csv)
  if schema_csv
    internal_execute("SET search_path TO #{schema_csv}")
    @schema_search_path = schema_csv
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1046

def add_column_for_alter(table_name, column_name, type, **options)
  return super unless options.key?(:comment)
  [super, Proc.new { change_column_comment(table_name, column_name, options[:comment]) }]
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 745

def add_exclusion_constraint(table_name, expression, **options)
  options = exclusion_constraint_options(table_name, expression, options)
  at = create_alter_table(table_name)
  at.add_exclusion_constraint(expression, options)

  execute schema_creation.accept(at)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 578

def add_foreign_key(from_table, to_table, **options)
  assert_valid_deferrable(options[:deferrable])

  super
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 529

def add_index(table_name, column_name, **options) # :nodoc:
  create_index = build_create_index_definition(table_name, column_name, **options)
  result = execute schema_creation.accept(create_index)

  index = create_index.index
  execute "COMMENT ON INDEX #{quote_column_name(index.name)} IS #{quote(index.comment)}" if index.comment
  result
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1066

def add_index_opclass(quoted_columns, **options)
  opclasses = options_for_index_columns(options[:opclass])
  quoted_columns.each do |name, column|
    column << " #{opclasses[name]}" if opclasses[name].present?
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 937

def add_index_options(table_name, column_name, **options) # :nodoc:
  if (where = options[:where]) && table_exists?(table_name) && column_exists?(table_name, where)
    options[:where] = quote_column_name(where)
  end
  super
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1073

def add_options_for_index_columns(quoted_columns, **options)
  quoted_columns = add_index_opclass(quoted_columns, **options)
  super
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 796

def add_unique_constraint(table_name, column_name = nil, **options)
  options = unique_constraint_options(table_name, column_name, options)
  at = create_alter_table(table_name)
  at.add_unique_constraint(column_name, options)

  execute schema_creation.accept(at)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1031

def assert_valid_deferrable(deferrable)
  return if !deferrable || %i(immediate deferred).include?(deferrable)

  raise ArgumentError, "deferrable must be `:immediate` or `:deferred`, got: `#{deferrable.inspect}`"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 489

def build_change_column_default_definition(table_name, column_name, default_or_changes) # :nodoc:
  column = column_for(table_name, column_name)
  return unless column

  default = extract_new_default_value(default_or_changes)
  ChangeColumnDefaultDefinition.new(column, default)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 478

def build_change_column_definition(table_name, column_name, type, **options) # :nodoc:
  td = create_table_definition(table_name)
  cd = td.new_column_definition(column_name, type, **options)
  ChangeColumnDefinition.new(cd, column_name)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 538

def build_create_index_definition(table_name, column_name, **options) # :nodoc:
  index, algorithm, if_not_exists = add_index_options(table_name, column_name, **options)
  CreateIndexDefinition.new(index, algorithm, if_not_exists)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 466

def change_column(table_name, column_name, type, **options) # :nodoc:
  clear_cache!
  sqls, procs = Array(change_column_for_alter(table_name, column_name, type, **options)).partition { |v| v.is_a?(String) }
  execute "ALTER TABLE #{quote_table_name(table_name)} #{sqls.join(", ")}"
  procs.each(&:call)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 509

def change_column_comment(table_name, column_name, comment_or_changes) # :nodoc:
  clear_cache!
  comment = extract_new_comment_value(comment_or_changes)
  execute "COMMENT ON COLUMN #{quote_table_name(table_name)}.#{quote_column_name(column_name)} IS #{quote(comment)}"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 485

def change_column_default(table_name, column_name, default_or_changes) # :nodoc:
  execute "ALTER TABLE #{quote_table_name(table_name)} #{change_column_default_for_alter(table_name, column_name, default_or_changes)}"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1051

def change_column_for_alter(table_name, column_name, type, **options)
  change_col_def = build_change_column_definition(table_name, column_name, type, **options)
  sqls = [schema_creation.accept(change_col_def)]
  sqls << Proc.new { change_column_comment(table_name, column_name, options[:comment]) } if options.key?(:comment)
  sqls
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 497

def change_column_null(table_name, column_name, null, default = nil) # :nodoc:
  validate_change_column_null_argument!(null)

  clear_cache!
  unless null || default.nil?
    column = column_for(table_name, column_name)
    execute "UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote_default_expression(default, column)} WHERE #{quote_column_name(column_name)} IS NULL" if column
  end
  execute "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1058

def change_column_null_for_alter(table_name, column_name, null, default = nil)
  if default.nil?
    "ALTER COLUMN #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL"
  else
    Proc.new { change_column_null(table_name, column_name, null, default) }
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 516

def change_table_comment(table_name, comment_or_changes) # :nodoc:
  clear_cache!
  comment = extract_new_comment_value(comment_or_changes)
  execute "COMMENT ON TABLE #{quote_table_name(table_name)} IS #{quote(comment)}"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 637

def check_constraints(table_name) # :nodoc:
  scope = quoted_scope(table_name)

  check_info = internal_exec_query(<<-SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
    SELECT conname, pg_get_constraintdef(c.oid, true) AS constraintdef, c.convalidated AS valid
    FROM pg_constraint c
    JOIN pg_class t ON c.conrelid = t.oid
    JOIN pg_namespace n ON n.oid = c.connamespace
    WHERE c.contype = 'c'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
  SQL

  check_info.map do |row|
    options = {
      name: row["conname"],
      validate: row["valid"]
    }
    expression = row["constraintdef"][/CHECK \((.+)\)/m, 1]

    CheckConstraintDefinition.new(table_name, expression, options)
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 235

def collation
  query_value("SELECT datcollate FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1152

def column_names_from_column_numbers(table_oid, column_numbers)
  Hash[query(<<~SQL, "SCHEMA")].values_at(*column_numbers).compact
    SELECT a.attnum, a.attname
    FROM pg_attribute a
    WHERE a.attrelid = #{table_oid}
    AND a.attnum IN (#{column_numbers.join(", ")})
  SQL
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 868

def columns_for_distinct(columns, orders) # :nodoc:
  order_columns = orders.compact_blank.map { |s|
    # Convert Arel node to string
    s = visitor.compile(s) unless s.is_a?(String)
    # Remove any ASC/DESC modifiers
    s.gsub(/\s+(?:ASC|DESC)\b/i, "")
     .gsub(/\sNULLS\s(?:FIRST|LAST)\b/i, "")
  }.compact_blank.map.with_index { |column, i| "#{column} AS alias_#{i}" }

  (order_columns << super).join(", ")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 962

def create_alter_table(name)
  PostgreSQL::AlterTable.new create_table_definition(name)
end

# 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.each_with_object(+"") do |(key, value), memo|
    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

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 256

def create_schema(schema_name, force: nil, if_not_exists: nil)
  if force && if_not_exists
    raise ArgumentError, "Options `:force` and `:if_not_exists` cannot be used simultaneously."
  end

  if force
    drop_schema(schema_name, if_exists: true)
  end

  execute("CREATE SCHEMA#{' IF NOT EXISTS' if if_not_exists} #{quote_schema_name(schema_name)}")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 884

def create_schema_dumper(options) # :nodoc:
  PostgreSQL::SchemaDumper.create(self, options)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 958

def create_table_definition(name, **options)
  PostgreSQL::TableDefinition.new(self, name, **options)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 240

def ctype
  query_value("SELECT datctype FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 220

def current_database
  query_value("SELECT current_database()", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 225

def current_schema
  query_value("SELECT current_schema", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1118

def data_source_sql(name = nil, type: nil)
  scope = quoted_scope(name, type: type)
  scope[:type] ||= "'r','v','m','p','f'" # (r)elation/table, (v)iew, (m)aterialized view, (p)artitioned table, (f)oreign table

  sql = +"SELECT c.relname FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = c.relnamespace"
  sql << " WHERE n.nspname = #{scope[:schema]}"
  sql << " AND c.relname = #{scope[:name]}" if scope[:name]
  sql << " AND c.relkind IN (#{scope[:type]})"
  sql
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 301

def default_sequence_name(table_name, pk = "id") # :nodoc:
  return nil if pk.is_a?(Array)

  result = serial_sequence(table_name, pk)
  return nil unless result
  Utils.extract_schema_qualified_name(result).to_s
rescue ActiveRecord::StatementInvalid
  PostgreSQL::Name.new(nil, "#{table_name}_#{pk}_seq").to_s
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 53

def drop_database(name) # :nodoc:
  execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 269

def drop_schema(schema_name, **options)
  execute "DROP SCHEMA#{' IF EXISTS' if options[:if_exists]} #{quote_schema_name(schema_name)} CASCADE"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 57

def drop_table(*table_names, **options) # :nodoc:
  table_names.each { |table_name| schema_cache.clear_data_source_cache!(table_name.to_s) }
  execute "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{table_names.map { |table_name| quote_table_name(table_name) }.join(', ')}#{' CASCADE' if options[:force] == :cascade}"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 230

def encoding
  query_value("SELECT pg_encoding_to_char(encoding) FROM pg_database WHERE datname = current_database()", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1088

def exclusion_constraint_for(table_name, **options)
  excl_name = exclusion_constraint_name(table_name, **options)
  exclusion_constraints(table_name).detect { |excl| excl.name == excl_name }
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1093

def exclusion_constraint_for!(table_name, expression: nil, **options)
  exclusion_constraint_for(table_name, expression: expression, **options) ||
    raise(ArgumentError, "Table '#{table_name}' has no exclusion constraint for #{expression || options}")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1078

def exclusion_constraint_name(table_name, **options)
  options.fetch(:name) do
    expression = options.fetch(:expression)
    identifier = "#{table_name}_#{expression}_excl"
    hashed_identifier = Digest::SHA256.hexdigest(identifier).first(10)

    "excl_rails_#{hashed_identifier}"
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 753

def exclusion_constraint_options(table_name, expression, options) # :nodoc:
  assert_valid_deferrable(options[:deferrable])

  options = options.dup
  options[:name] ||= exclusion_constraint_name(table_name, expression: expression, **options)
  options
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 663

def exclusion_constraints(table_name)
  scope = quoted_scope(table_name)

  exclusion_info = internal_exec_query(<<-SQL, "SCHEMA")
    SELECT conname, pg_get_constraintdef(c.oid) AS constraintdef, c.condeferrable, c.condeferred
    FROM pg_constraint c
    JOIN pg_class t ON c.conrelid = t.oid
    JOIN pg_namespace n ON n.oid = c.connamespace
    WHERE c.contype = 'x'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
  SQL

  exclusion_info.map do |row|
    method_and_elements, predicate = row["constraintdef"].split(" WHERE ")
    method_and_elements_parts = method_and_elements.match(/EXCLUDE(?: USING (?<using>\S+))? \((?<expression>.+)\)/)
    predicate.remove!(/ DEFERRABLE(?: INITIALLY (?:IMMEDIATE|DEFERRED))?/) if predicate
    predicate = predicate.from(2).to(-3) if predicate # strip 2 opening and closing parentheses

    deferrable = extract_constraint_deferrable(row["condeferrable"], row["condeferred"])

    options = {
      name: row["conname"],
      using: method_and_elements_parts["using"].to_sym,
      where: predicate,
      deferrable: deferrable
    }

    ExclusionConstraintDefinition.new(table_name, method_and_elements_parts["expression"], options)
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1037

def extract_constraint_deferrable(deferrable, deferred)
  deferrable && (deferred ? :deferred : :immediate)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1023

def extract_foreign_key_action(specifier)
  case specifier
  when "c"; :cascade
  when "n"; :nullify
  when "r"; :restrict
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1147

def extract_schema_qualified_name(string)
  name = Utils.extract_schema_qualified_name(string.to_s)
  [name.schema, name.identifier]
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 995

def fetch_type_metadata(column_name, sql_type, oid, fmod)
  cast_type = get_oid_type(oid, fmod, column_name, sql_type)
  simple_type = SqlTypeMetadata.new(
    sql_type: sql_type,
    type: cast_type.type,
    limit: cast_type.limit,
    precision: cast_type.precision,
    scale: cast_type.scale,
  )
  PostgreSQL::TypeMetadata.new(simple_type, oid: oid, fmod: fmod)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 932

def foreign_key_column_for(table_name, column_name) # :nodoc:
  _schema, table_name = extract_schema_qualified_name(table_name)
  super
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 584

def foreign_keys(table_name)
  scope = quoted_scope(table_name)
  fk_info = internal_exec_query(<<~SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
    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, c.condeferrable AS deferrable, c.condeferred AS deferred, c.conkey, c.confkey, c.conrelid, c.confrelid
    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|
    to_table = Utils.unquote_identifier(row["to_table"])
    conkey = row["conkey"].scan(/\d+/).map(&:to_i)
    confkey = row["confkey"].scan(/\d+/).map(&:to_i)

    if conkey.size > 1
      column = column_names_from_column_numbers(row["conrelid"], conkey)
      primary_key = column_names_from_column_numbers(row["confrelid"], confkey)
    else
      column = Utils.unquote_identifier(row["column"])
      primary_key = row["primary_key"]
    end

    options = {
      column: column,
      name: row["name"],
      primary_key: primary_key
    }

    options[:on_delete] = extract_foreign_key_action(row["on_delete"])
    options[:on_update] = extract_foreign_key_action(row["on_update"])
    options[:deferrable] = extract_constraint_deferrable(row["deferrable"], row["deferred"])

    options[:validate] = row["valid"]

    ForeignKeyDefinition.new(table_name, to_table, options)
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 633

def foreign_table_exists?(table_name)
  query_values(data_source_sql(table_name, type: "FOREIGN TABLE"), "SCHEMA").any? if table_name.present?
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 629

def foreign_tables
  query_values(data_source_sql(type: "FOREIGN TABLE"), "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 573

def index_name(table_name, options) # :nodoc:
  _schema, table_name = extract_schema_qualified_name(table_name.to_s)
  super
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 68

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 = t.relnamespace
    WHERE i.relkind IN ('i', 'I')
      AND i.relname = #{index[:name]}
      AND t.relname = #{table[:name]}
      AND n.nspname = #{table[:schema]}
  SQL
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 86

def indexes(table_name) # :nodoc:
  scope = quoted_scope(table_name)

  result = query(<<~SQL, "SCHEMA")
    SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,
                    pg_catalog.obj_description(i.oid, 'pg_class') AS comment, d.indisvalid
    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 = t.relnamespace
    WHERE i.relkind IN ('i', 'I')
      AND d.indisprimary = 'f'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
    ORDER BY i.relname
  SQL

  result.map do |row|
    index_name = row[0]
    unique = row[1]
    indkey = row[2].split(" ").map(&:to_i)
    inddef = row[3]
    oid = row[4]
    comment = row[5]
    valid = row[6]
    using, expressions, include, nulls_not_distinct, where = inddef.scan(/ USING (\w+?) \((.+?)\)(?: INCLUDE \((.+?)\))?( NULLS NOT DISTINCT)?(?: WHERE (.+))?\z/m).flatten

    orders = {}
    opclasses = {}
    include_columns = include ? include.split(",").map { |c| Utils.unquote_identifier(c.strip.gsub('""', '"')) } : []

    if indkey.include?(0)
      columns = expressions
    else
      columns = column_names_from_column_numbers(oid, indkey)

      # prevent INCLUDE columns from being matched
      columns.reject! { |c| include_columns.include?(c) }

      # add info on sort order (only desc order is explicitly specified, asc is the default)
      # and non-default opclasses
      expressions.scan(/(?<column>\w)"?\s?(?<opclass>\w_ops(_\w+)?)?\s?(?<desc>DESC)?\s?(?<nulls>NULLS (?:FIRST|LAST))?/).each do |column, opclass, desc, nulls|
        opclasses[column] = opclass.to_sym if opclass
        if nulls
          orders[column] = [desc, nulls].compact.join(" ")
        else
          orders[column] = :desc if desc
        end
      end
    end

    IndexDefinition.new(
      table_name,
      index_name,
      unique,
      columns,
      orders: orders,
      opclasses: opclasses,
      where: where,
      using: using.to_sym,
      include: include_columns.presence,
      nulls_not_distinct: nulls_not_distinct.present?,
      comment: comment.presence,
      valid: valid
    )
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 204

def inherited_table_names(table_name) # :nodoc:
  scope = quoted_scope(table_name, type: "BASE TABLE")

  query_values(<<~SQL, "SCHEMA")
    SELECT parent.relname
    FROM pg_catalog.pg_inherits i
      JOIN pg_catalog.pg_class child ON i.inhrelid = child.oid
      JOIN pg_catalog.pg_class parent ON i.inhparent = parent.oid
      LEFT JOIN pg_namespace n ON n.oid = child.relnamespace
    WHERE child.relname = #{scope[:name]}
      AND child.relkind IN (#{scope[:type]})
      AND n.nspname = #{scope[:schema]}
  SQL
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 966

def new_column_from_field(table_name, field, _definitions)
  column_name, type, default, notnull, oid, fmod, collation, comment, identity, attgenerated = field
  type_metadata = fetch_type_metadata(column_name, type, oid.to_i, fmod.to_i)
  default_value = extract_value_from_default(default)

  if attgenerated.present?
    default_function = default
  else
    default_function = extract_default_function(default_value, default)
  end

  if match = default_function&.match(/\Anextval\('"?(?<sequence_name>.+_(?<suffix>seq\d*))"?'::regclass\)\z/)
    serial = sequence_name_from_parts(table_name, column_name, match[:suffix]) == match[:sequence_name]
  end

  PostgreSQL::Column.new(
    column_name,
    default_value,
    type_metadata,
    !notnull,
    default_function,
    collation: collation,
    comment: comment.presence,
    serial: serial,
    identity: identity.presence,
    generated: attgenerated
  )
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 359

def pk_and_sequence_for(table) # :nodoc:
  # First try looking for a sequence with a dependency on the
  # given table's primary key.
  result = query(<<~SQL, "SCHEMA")[0]
    SELECT attr.attname, nsp.nspname, seq.relname
    FROM pg_class      seq,
         pg_attribute  attr,
         pg_depend     dep,
         pg_constraint cons,
         pg_namespace  nsp
    WHERE seq.oid           = dep.objid
      AND seq.relkind       = 'S'
      AND attr.attrelid     = dep.refobjid
      AND attr.attnum       = dep.refobjsubid
      AND attr.attrelid     = cons.conrelid
      AND attr.attnum       = cons.conkey[1]
      AND seq.relnamespace  = nsp.oid
      AND cons.contype      = 'p'
      AND dep.classid       = 'pg_class'::regclass
      AND dep.refobjid      = #{quote(quote_table_name(table))}::regclass
  SQL

  if result.nil? || result.empty?
    result = query(<<~SQL, "SCHEMA")[0]
      SELECT attr.attname, nsp.nspname,
        CASE
          WHEN pg_get_expr(def.adbin, def.adrelid) !~* 'nextval' THEN NULL
          WHEN split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2) ~ '.' THEN
            substr(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2),
                   strpos(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), '.')+1)
          ELSE split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2)
        END
      FROM pg_class       t
      JOIN pg_attribute   attr ON (t.oid = attrelid)
      JOIN pg_attrdef     def  ON (adrelid = attrelid AND adnum = attnum)
      JOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])
      JOIN pg_namespace   nsp  ON (t.relnamespace = nsp.oid)
      WHERE t.oid = #{quote(quote_table_name(table))}::regclass
        AND cons.contype = 'p'
        AND pg_get_expr(def.adbin, def.adrelid) ~* 'nextval|uuid_generate|gen_random_uuid'
    SQL
  end

  pk = result.shift
  if result.last
    [pk, PostgreSQL::Name.new(*result)]
  else
    [pk, nil]
  end
rescue
  nil
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 412

def primary_keys(table_name) # :nodoc:
  query_values(<<~SQL, "SCHEMA")
    SELECT a.attname
      FROM (
             SELECT indrelid, indkey, generate_subscripts(indkey, 1) idx
               FROM pg_index
              WHERE indrelid = #{quote(quote_table_name(table_name))}::regclass
                AND indisprimary
           ) i
      JOIN pg_attribute a
        ON a.attrelid = i.indrelid
       AND a.attnum = i.indkey[i.idx]
     ORDER BY i.idx
  SQL
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 944

def quoted_include_columns_for_index(column_names) # :nodoc:
  return quote_column_name(column_names) if column_names.is_a?(Symbol)

  quoted_columns = column_names.each_with_object({}) do |name, result|
    result[name.to_sym] = quote_column_name(name).dup
  end
  add_options_for_index_columns(quoted_columns).values.join(", ")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1129

def quoted_scope(name = nil, type: nil)
  schema, name = extract_schema_qualified_name(name)
  type = \
    case type
    when "BASE TABLE"
      "'r','p'"
    when "VIEW"
      "'v','m'"
    when "FOREIGN TABLE"
      "'f'"
    end
  scope = {}
  scope[:schema] = schema ? quote(schema) : "ANY (current_schemas(false))"
  scope[:name] = quote(name) if name
  scope[:type] = type if type
  scope
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 9

def recreate_database(name, options = {}) # :nodoc:
  drop_database(name)
  create_database(name, options)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1041

def reference_name_for_table(table_name)
  _schema, table_name = extract_schema_qualified_name(table_name.to_s)
  table_name.singularize
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 768

def remove_exclusion_constraint(table_name, expression = nil, **options)
  excl_name_to_delete = exclusion_constraint_for!(table_name, expression: expression, **options).name

  remove_constraint(table_name, excl_name_to_delete)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 543

def remove_index(table_name, column_name = nil, **options) # :nodoc:
  table = Utils.extract_schema_qualified_name(table_name.to_s)

  if options.key?(:name)
    provided_index = Utils.extract_schema_qualified_name(options[:name].to_s)

    options[:name] = provided_index.identifier
    table = PostgreSQL::Name.new(provided_index.schema, table.identifier) unless table.schema.present?

    if provided_index.schema.present? && table.schema != provided_index.schema
      raise ArgumentError.new("Index schema '#{provided_index.schema}' does not match table schema '#{table.schema}'")
    end
  end

  return if options[:if_exists] && !index_exists?(table_name, column_name, **options)

  index_to_remove = PostgreSQL::Name.new(table.schema, index_name_for_remove(table.to_s, column_name, options))

  execute "DROP INDEX #{index_algorithm(options[:algorithm])} #{quote_table_name(index_to_remove)}"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 823

def remove_unique_constraint(table_name, column_name = nil, **options)
  unique_name_to_delete = unique_constraint_for!(table_name, column: column_name, **options).name

  remove_constraint(table_name, unique_name_to_delete)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 523

def rename_column(table_name, column_name, new_column_name) # :nodoc:
  clear_cache!
  execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
  rename_column_indexes(table_name, column_name, new_column_name)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 566

def rename_index(table_name, old_name, new_name)
  validate_index_length!(table_name, new_name)

  schema, = extract_schema_qualified_name(table_name)
  execute "ALTER INDEX #{quote_table_name(schema) + '.' if schema}#{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 434

def rename_table(table_name, new_name, **options)
  validate_table_length!(new_name) unless options[:_uses_legacy_table_name]
  clear_cache!
  schema_cache.clear_data_source_cache!(table_name.to_s)
  schema_cache.clear_data_source_cache!(new_name.to_s)
  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
    # PostgreSQL automatically creates an index for PRIMARY KEY with name consisting of
    # truncated table name and "_pkey" suffix fitting into max_identifier_length number of characters.
    max_pkey_prefix = max_identifier_length - "_pkey".size
    idx = "#{table_name[0, max_pkey_prefix]}_pkey"
    new_idx = "#{new_name[0, max_pkey_prefix]}_pkey"
    execute "ALTER INDEX #{quote_table_name(idx)} RENAME TO #{quote_table_name(new_idx)}"

    # PostgreSQL automatically creates a sequence for PRIMARY KEY with name consisting of
    # truncated table name and "#{primary_key}_seq" suffix fitting into max_identifier_length number of characters.
    max_seq_prefix = max_identifier_length - "_#{pk}_seq".size
    if seq && seq.identifier == "#{table_name[0, max_seq_prefix]}_#{pk}_seq"
      new_seq = "#{new_name[0, max_seq_prefix]}_#{pk}_seq"
      execute "ALTER TABLE #{seq.quoted} RENAME TO #{quote_table_name(new_seq)}"
    end
  end
  rename_table_indexes(table_name, new_name, **options)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 331

def reset_pk_sequence!(table, pk = nil, sequence = nil) # :nodoc:
  unless pk && sequence
    default_pk, default_sequence = pk_and_sequence_for(table)

    pk ||= default_pk
    sequence ||= default_sequence
  end

  if @logger && pk && !sequence
    @logger.warn "#{table} has primary key #{pk} with no default sequence."
  end

  if pk && sequence
    quoted_sequence = quote_table_name(sequence)
    max_pk = query_value("SELECT MAX(#{quote_column_name pk}) FROM #{quote_table_name(table)}", "SCHEMA")
    if max_pk.nil?
      if database_version >= 10_00_00
        minvalue = query_value("SELECT seqmin FROM pg_sequence WHERE seqrelid = #{quote(quoted_sequence)}::regclass", "SCHEMA")
      else
        minvalue = query_value("SELECT min_value FROM #{quoted_sequence}", "SCHEMA")
      end
    end

    query_value("SELECT setval(#{quote(quoted_sequence)}, #{max_pk || minvalue}, #{max_pk ? true : false})", "SCHEMA")
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 953

def schema_creation  # :nodoc:
  PostgreSQL::SchemaCreation.new(self)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 63

def schema_exists?(name)
  query_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = #{quote(name)}", "SCHEMA").to_i > 0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 245

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

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1007

def sequence_name_from_parts(table_name, column_name, suffix)
  over_length = [table_name, column_name, suffix].sum(&:length) + 2 - max_identifier_length

  if over_length > 0
    column_name_length = [(max_identifier_length - suffix.length - 2) / 2, column_name.length].min
    over_length -= column_name.length - column_name_length
    column_name = column_name[0, column_name_length - [over_length, 0].min]
  end

  if over_length > 0
    table_name = table_name[0, table_name.length - over_length]
  end

  "#{table_name}_#{column_name}_#{suffix}"
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 311

def serial_sequence(table, column)
  query_value("SELECT pg_get_serial_sequence(#{quote(table)}, #{quote(column)})", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 316

def set_pk_sequence!(table, value) # :nodoc:
  pk, sequence = pk_and_sequence_for(table)

  if pk
    if sequence
      quoted_sequence = quote_table_name(sequence)

      query_value("SELECT setval(#{quote(quoted_sequence)}, #{value})", "SCHEMA")
    else
      @logger.warn "#{table} has primary key #{pk} with no default sequence." if @logger
    end
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 175

def table_comment(table_name) # :nodoc:
  scope = quoted_scope(table_name, type: "BASE TABLE")
  if scope[:name]
    query_value(<<~SQL, "SCHEMA")
      SELECT pg_catalog.obj_description(c.oid, 'pg_class')
      FROM pg_catalog.pg_class c
        LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
      WHERE c.relname = #{scope[:name]}
        AND c.relkind IN (#{scope[:type]})
        AND n.nspname = #{scope[:schema]}
    SQL
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 154

def table_options(table_name) # :nodoc:
  options = {}

  comment = table_comment(table_name)

  options[:comment] = comment if comment

  inherited_table_names = inherited_table_names(table_name).presence

  options[:options] = "INHERITS (#{inherited_table_names.join(", ")})" if inherited_table_names

  if !options[:options] && supports_native_partitioning?
    partition_definition = table_partition_definition(table_name)

    options[:options] = "PARTITION BY #{partition_definition}" if partition_definition
  end

  options
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 190

def table_partition_definition(table_name) # :nodoc:
  scope = quoted_scope(table_name, type: "BASE TABLE")

  query_value(<<~SQL, "SCHEMA")
    SELECT pg_catalog.pg_get_partkeydef(c.oid)
    FROM pg_catalog.pg_class c
      LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
    WHERE c.relname = #{scope[:name]}
      AND c.relkind IN (#{scope[:type]})
      AND n.nspname = #{scope[:schema]}
  SQL
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 830

def type_to_sql(type, limit: nil, precision: nil, scale: nil, array: nil, enum_type: nil, **) # :nodoc:
  sql = \
    case type.to_s
    when "binary"
      # PostgreSQL doesn't support limits on binary (bytea) columns.
      # The hard limit is 1GB, because of a 32-bit size field, and TOAST.
      case limit
      when nil, 0..0x3fffffff; super(type)
      else raise ArgumentError, "No binary type has byte size #{limit}. The limit on binary can be at most 1GB - 1byte."
      end
    when "text"
      # PostgreSQL doesn't support limits on text columns.
      # The hard limit is 1GB, according to section 8.3 in the manual.
      case limit
      when nil, 0..0x3fffffff; super(type)
      else raise ArgumentError, "No text type has byte size #{limit}. The limit on text can be at most 1GB - 1byte."
      end
    when "integer"
      case limit
      when 1, 2; "smallint"
      when nil, 3, 4; "integer"
      when 5..8; "bigint"
      else raise ArgumentError, "No integer type has byte size #{limit}. Use a numeric with scale 0 instead."
      end
    when "enum"
      raise ArgumentError, "enum_type is required for enums" if enum_type.nil?

      enum_type
    else
      super
    end

  sql = "#{sql}[]" if array && type != :primary_key
  sql
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1108

def unique_constraint_for(table_name, **options)
  name = unique_constraint_name(table_name, **options) unless options.key?(:column)
  unique_constraints(table_name).detect { |unique_constraint| unique_constraint.defined_for?(name: name, **options) }
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1113

def unique_constraint_for!(table_name, column: nil, **options)
  unique_constraint_for(table_name, column: column, **options) ||
    raise(ArgumentError, "Table '#{table_name}' has no unique constraint for #{column || options}")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 1098

def unique_constraint_name(table_name, **options)
  options.fetch(:name) do
    column_or_index = Array(options[:column] || options[:using_index]).map(&:to_s)
    identifier = "#{table_name}_#{column_or_index * '_and_'}_unique"
    hashed_identifier = Digest::SHA256.hexdigest(identifier).first(10)

    "uniq_rails_#{hashed_identifier}"
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 804

def unique_constraint_options(table_name, column_name, options) # :nodoc:
  assert_valid_deferrable(options[:deferrable])

  if column_name && options[:using_index]
    raise ArgumentError, "Cannot specify both column_name and :using_index options."
  end

  options = options.dup
  options[:name] ||= unique_constraint_name(table_name, column: column_name, **options)
  options
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 697

def unique_constraints(table_name)
  scope = quoted_scope(table_name)

  unique_info = internal_exec_query(<<~SQL, "SCHEMA", allow_retry: true, materialize_transactions: false)
    SELECT c.conname, c.conrelid, c.conkey, c.condeferrable, c.condeferred, pg_get_constraintdef(c.oid) AS constraintdef
    FROM pg_constraint c
    JOIN pg_class t ON c.conrelid = t.oid
    JOIN pg_namespace n ON n.oid = c.connamespace
    WHERE c.contype = 'u'
      AND t.relname = #{scope[:name]}
      AND n.nspname = #{scope[:schema]}
  SQL

  unique_info.map do |row|
    conkey = row["conkey"].delete("{}").split(",").map(&:to_i)
    columns = column_names_from_column_numbers(row["conrelid"], conkey)

    nulls_not_distinct = row["constraintdef"].start_with?("UNIQUE NULLS NOT DISTINCT")
    deferrable = extract_constraint_deferrable(row["condeferrable"], row["condeferred"])

    options = {
      name: row["conname"],
      nulls_not_distinct: nulls_not_distinct,
      deferrable: deferrable
    }

    UniqueConstraintDefinition.new(table_name, columns, options)
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 880

def update_table_definition(table_name, base) # :nodoc:
  PostgreSQL::Table.new(table_name, base)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 926

def validate_check_constraint(table_name, **options)
  chk_name_to_validate = check_constraint_for!(table_name, **options).name

  validate_constraint table_name, chk_name_to_validate
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 893

def validate_constraint(table_name, constraint_name)
  at = create_alter_table table_name
  at.validate_constraint constraint_name

  execute schema_creation.accept(at)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 915

def validate_foreign_key(from_table, to_table = nil, **options)
  fk_name_to_validate = foreign_key_for!(from_table, to_table: to_table, **options).name

  validate_constraint from_table, fk_name_to_validate
end