libpqxx
The C++ client library for PostgreSQL
|
Nullness: Enums do not have an inherent null value. More...
Static Public Member Functions | |
static bool | is_null (ENUM const &value) |
Is value a null? | |
static ENUM | null () |
Return a null value. | |
Static Public Member Functions inherited from pqxx::no_null< ENUM > | |
static constexpr bool | is_null (ENUM const &) noexcept |
Does a given value correspond to an SQL null value? |
Static Public Attributes | |
static bool | has_null |
Does this type have a null value? | |
static bool | always_null |
Is this type always null? | |
Static Public Attributes inherited from pqxx::no_null< ENUM > | |
static constexpr bool | has_null |
Does TYPE have a "built-in null value"? | |
static constexpr bool | always_null |
Are all values of this type null? |
Nullness: Enums do not have an inherent null value.
|
staticnodiscard |
Return a null value.
Don't use this in generic code to compare a value and see whether it is null. Some types may have multiple null values which do not compare as equal, or may define a null value which is not equal to anything including itself, like in SQL.