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|
# frozen-string-literal: true
module Sequel
class Database
# ---------------------
# :section: 9 - Methods that describe what the database supports
# These methods all return booleans, with most describing whether or not the
# database supprots a given feature.
# ---------------------
# Whether the database uses a global namespace for the index, true by default. If
# false, the indexes are going to be namespaced per table.
def global_index_namespace?
true
end
# Whether the database supports CREATE TABLE IF NOT EXISTS syntax,
# false by default.
def supports_create_table_if_not_exists?
false
end
# Whether the database supports deferrable constraints, false
# by default as few databases do.
def supports_deferrable_constraints?
false
end
# Whether the database supports deferrable foreign key constraints,
# false by default as few databases do.
def supports_deferrable_foreign_key_constraints?
supports_deferrable_constraints?
end
# Whether the database supports DROP TABLE IF EXISTS syntax,
# false by default.
def supports_drop_table_if_exists?
supports_create_table_if_not_exists?
end
# Whether the database supports Database#foreign_key_list for
# parsing foreign keys.
def supports_foreign_key_parsing?
respond_to?(:foreign_key_list)
end
# Whether the database supports Database#indexes for parsing indexes.
def supports_index_parsing?
respond_to?(:indexes)
end
# Whether the database supports partial indexes (indexes on a subset of a table),
# false by default.
def supports_partial_indexes?
false
end
# Whether the database and adapter support prepared transactions
# (two-phase commit), false by default.
def supports_prepared_transactions?
false
end
# Whether the database and adapter support savepoints, false by default.
def supports_savepoints?
false
end
# Whether the database and adapter support savepoints inside prepared transactions
# (two-phase commit), false by default.
def supports_savepoints_in_prepared_transactions?
supports_prepared_transactions? && supports_savepoints?
end
# Whether the database supports schema parsing via Database#schema.
def supports_schema_parsing?
respond_to?(:schema_parse_table, true)
end
# Whether the database supports Database#tables for getting list of tables.
def supports_table_listing?
respond_to?(:tables)
end
#
# Whether the database supports Database#views for getting list of views.
def supports_view_listing?
respond_to?(:views)
end
# Whether the database and adapter support transaction isolation levels, false by default.
def supports_transaction_isolation_levels?
false
end
# Whether DDL statements work correctly in transactions, false by default.
def supports_transactional_ddl?
false
end
# Whether CREATE VIEW ... WITH CHECK OPTION is supported, false by default.
def supports_views_with_check_option?
!!view_with_check_option_support
end
# Whether CREATE VIEW ... WITH LOCAL CHECK OPTION is supported, false by default.
def supports_views_with_local_check_option?
view_with_check_option_support == :local
end
private
# Whether the database supports adding primary key constraints on NULLable columns,
# automatically making them NOT NULL. If false, the columns must be set NOT NULL
# before the primary key constraint is added.
def can_add_primary_key_constraint_on_nullable_columns?
true
end
# Whether this dataset considers unquoted identifiers as uppercase. True
# by default as that is the SQL standard
def folds_unquoted_identifiers_to_uppercase?
true
end
# Whether the database supports combining multiple alter table
# operations into a single query, false by default.
def supports_combining_alter_table_ops?
false
end
# Whether the database supports CREATE OR REPLACE VIEW. If not, support
# will be emulated by dropping the view first. false by default.
def supports_create_or_replace_view?
false
end
# Whether the database supports named column constraints. True
# by default. Those that don't support named column constraints
# have to have column constraints converted to table constraints
# if the column constraints have names.
def supports_named_column_constraints?
true
end
# Don't advertise support for WITH CHECK OPTION by default.
def view_with_check_option_support
nil
end
end
end
|
