Using temporal types as the primary key of a table is risky. When these types are used as primary keys, it usually means that each new key is
created with the use of .Now
or .UtcNow
properties from DateTime
and DateTimeOffset
classes. In
those cases, duplicate keys exceptions may occur in many ways:
- when entries are added consecutively by a machine with low-enough system clock resolution;
- when two different threads are inserting entries in close enough sequence for both to have the same time;
- when changes such as daylight saving time (DST) transitions occur, where values can be repeated the following hour (only for
DateTime
type);
The rule raises an issue if:
- Entity Framework, or Entity Framework Core dependencies are found;
- a class contains a property either named
Id
, <type name>Id
or decorated by the [Key]
or
[PrimaryKey]
attribute.
- the key property is of one of the following types: