All elements of a database schema are grouped into logical units
            called modules.  A module has a name that is unique inside a database.
            The same schema object name can be used in different modules without
            conflict.  For example, both module1 and module2 can contain
            a User object type.
Schema objects can be referred to by a fully-qualified name using the
            <module>::<name> notation.
Every EdgeDB schema contains the following standard modules:
std: standard types, functions and other declarations
schema: types describing the introspection
                    schema
sys: system-wide entities, such as user roles and
                    databases
cfg: configuration and settings
stdgraphql: GraphQL-related types
math: algebraic and statistical functions
default: the default module for user-defined types, functions, etc.