Class: ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 29

class_attribute :emulate_booleans, default: true

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 29

class_attribute :emulate_booleans, default: true

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

def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 161

def supports_advisory_locks?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 96

def supports_bulk_alter?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 128

def supports_check_constraints?
  if mariadb?
    database_version >= "10.3.10" || (database_version < "10.3" && database_version >= "10.2.22")
  else
    database_version >= "8.0.16"
  end
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 153

def supports_common_table_expressions?
  if mariadb?
    database_version >= "10.2.1"
  else
    database_version >= "8.0.1"
  end
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 140

def supports_datetime_with_precision?
  mariadb? || database_version >= "5.6.4"
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 116

def supports_explain?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 104

def supports_expression_index?
  !mariadb? && database_version >= "8.0.13"
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 124

def supports_foreign_keys?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 100

def supports_index_sort_order?
  !mariadb? && database_version >= "8.0.1"
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 120

def supports_indexes_in_create?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 165

def supports_insert_on_duplicate_skip?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 169

def supports_insert_on_duplicate_update?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 149

def supports_optimizer_hints?
  !mariadb? && database_version >= "5.7.7"
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 112

def supports_restart_db_transaction?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 108

def supports_transaction_isolation?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 136

def supports_views?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 144

def supports_virtual_columns?
  mariadb? || database_version >= "5.7.5"
end

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

def check_constraints(table_name)
  if supports_check_constraints?
    scope = quoted_scope(table_name)

    sql = <<~SQL
      SELECT cc.constraint_name AS 'name',
            cc.check_clause AS 'expression'
      FROM information_schema.check_constraints cc
      JOIN information_schema.table_constraints tc
      USING (constraint_schema, constraint_name)
      WHERE tc.table_schema = #{scope[:schema]}
        AND tc.table_name = #{scope[:name]}
        AND cc.constraint_schema = #{scope[:schema]}
    SQL
    sql += " AND cc.table_name = #{scope[:name]}" if mariadb?

    chk_info = internal_exec_query(sql, "SCHEMA")

    chk_info.map do |row|
      options = {
        name: row["name"]
      }
      expression = row["expression"]
      expression = expression[1..-2] if expression.start_with?("(") && expression.end_with?(")")
      expression = strip_whitespace_characters(expression)

      unless mariadb?
        # MySQL returns check constraints expression in an already escaped form.
        # This leads to duplicate escaping later (e.g. when the expression is used in the SchemaDumper).
        expression = expression.gsub("\\'", "'")
      end

      CheckConstraintDefinition.new(table_name, expression, options)
    end
  else
    raise NotImplementedError
  end
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 309

def collation
  show_variable "collation_database"
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 279

def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT COLLATE #{quote_table_name(options[:collation])}"
  elsif options[:charset]
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset])}"
  elsif row_format_dynamic_by_default?
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET `utf8mb4`"
  else
    raise "Configure a supported :charset and ensure innodb_large_prefix is enabled to support indexes on varchar(255) string columns."
  end
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 299

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

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 357

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

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 464

def foreign_keys(table_name)
  raise ArgumentError unless table_name.present?

  scope = quoted_scope(table_name)

  # MySQL returns 1 row for each column of composite foreign keys.
  fk_info = internal_exec_query(<<~SQL, "SCHEMA")
    SELECT fk.referenced_table_name AS 'to_table',
           fk.referenced_column_name AS 'primary_key',
           fk.column_name AS 'column',
           fk.constraint_name AS 'name',
           fk.ordinal_position AS 'position',
           rc.update_rule AS 'on_update',
           rc.delete_rule AS 'on_delete'
    FROM information_schema.referential_constraints rc
    JOIN information_schema.key_column_usage fk
    USING (constraint_schema, constraint_name)
    WHERE fk.referenced_column_name IS NOT NULL
      AND fk.table_schema = #{scope[:schema]}
      AND fk.table_name = #{scope[:name]}
      AND rc.constraint_schema = #{scope[:schema]}
      AND rc.table_name = #{scope[:name]}
  SQL

  grouped_fk = fk_info.group_by { |row| row["name"] }.values.each { |group| group.sort_by! { |row| row["position"] } }
  grouped_fk.map do |group|
    row = group.first
    options = {
      name: row["name"],
      on_update: extract_foreign_key_action(row["on_update"]),
      on_delete: extract_foreign_key_action(row["on_delete"])
    }

    if group.one?
      options[:column] = unquote_identifier(row["column"])
      options[:primary_key] = row["primary_key"]
    else
      options[:column] = group.map { |row| unquote_identifier(row["column"]) }
      options[:primary_key] = group.map { |row| row["primary_key"] }
    end

    ForeignKeyDefinition.new(table_name, unquote_identifier(row["to_table"]), options)
  end
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 185

def index_algorithms
  {
    default: "ALGORITHM = DEFAULT",
    copy:    "ALGORITHM = COPY",
    inplace: "ALGORITHM = INPLACE",
    instant: "ALGORITHM = INSTANT",
  }
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 181

def native_database_types
  NATIVE_DATABASE_TYPES
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 265

def recreate_database(name, options = {})
  drop_database(name)
  sql = create_database(name, options)
  reconnect!
  sql
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 362

def rename_index(table_name, old_name, new_name)
  if supports_rename_index?
    validate_index_length!(table_name, new_name)

    execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"
  else
    super
  end
end

# File 'activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 334

def rename_table(table_name, new_name, **options)
  validate_table_length!(new_name) unless options[:_uses_legacy_table_name]
  schema_cache.clear_data_source_cache!(table_name.to_s)
  schema_cache.clear_data_source_cache!(new_name.to_s)
  execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
  rename_table_indexes(table_name, new_name, **options)
end

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

def show_variable(name)
  query_value("SELECT @@#{name}", "SCHEMA")
rescue ActiveRecord::StatementInvalid
  nil
end