@type context_name() :: atom() | nil

An application wide designation for application defined datastore access accounts.

@type context_role() :: String.t()

The database role name for the specific access context defined by the context_name().

@type context_state_values() ::
  :not_found | :not_ready | :ready | :not_started | :started

Defines the available states in which a context may exist.

• :not_found - The database role backing the context was not found on the Datastore database server.

• :not_ready - The database role backing the context exists, but is not completely set up yet. This is an interim stage that usually has to cross transaction boundaries.

• :not_started - When starting contexts the system doesn't check for the existence of each context which in turn means that a start failure could be indicative of either non-existence or some other problem. In these start-up scenarios the state would be :not_started.

• :ready - The context was found and may be connected to the database, but the database connections for the context have not been started yet.

• :started - The context was found and database connections for the context have already been started.

@type database_state_values() :: :not_found | :ready

Values indicating the state of the database which backs a given Datastore.

• :not_found - The database for the Datastore does not exist on the database server.

• :ready - The database is ready for further processing by the migrations subsystem.

@type db_type_comparison_operators() :: :gt | :lt | :eq | :lcr | :rcl | :gto | :lto

Defines operators for use in comparison functions.

These operators are used in conjunction with the MscmpSystDb.DbTypes and MscmpSystDb.DbTypes.Range protocols.

The range related operator values are generally the same as those defined by the PostgreSQL database range types, but there are some small differences.

• :gt - left is greater than right.

• :lt - left is less than right.

• :eq - the values are equal.

• :lcr - left contains right.

• :rcl - right contains left.

• :gto - greater than overlapping.

• :lto - less than overlapping.

Examples

Greater Than (:gt)

iex> left_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 200,
...>     upper: 210
...>   }
iex> right_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 110
...>   }
iex> MscmpSystDb.DbTypes.compare(left_range, right_range)
:gt

Less Than (:lt)

iex> left_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 110
...>   }
iex> right_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 200,
...>     upper: 210
...>   }
iex> MscmpSystDb.DbTypes.compare(left_range, right_range)
:lt

Equal (:eq)

iex> left_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 110
...>   }
iex> right_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 110
...>   }
iex> MscmpSystDb.DbTypes.compare(left_range, right_range)
:eq

Left Contains Right (:lcr)

iex> left_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 90,
...>     upper: 110
...>   }
iex> right_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 110
...>   }
iex> MscmpSystDb.DbTypes.compare(left_range, right_range)
:lcr

Right Contains Left (:rcl)

iex> left_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 110
...>   }
iex> right_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 111
...>   }
iex> MscmpSystDb.DbTypes.compare(left_range, right_range)
:rcl

Greater Than Overlapping (:gto)

iex> left_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 150,
...>     upper: 250
...>   }
iex> right_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 175
...>   }
iex> MscmpSystDb.DbTypes.compare(left_range, right_range)
:gto

Less Than Overlapping (:lto)

iex> left_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 100,
...>     upper: 150
...>   }
iex> right_range =
...>   %MscmpSystDb.DbTypes.IntegerRange{
...>     lower: 125,
...>     upper: 175
...>   }
iex> MscmpSystDb.DbTypes.compare(left_range, right_range)
:lto

@type migration_state_values() :: :not_initialized | :not_updated | :ready

Defines the available states in which a Datastore might exist in relation to its schema migrations.

• :not_initialized - The Datastore does not have the table which manages the migrations installed. This is also the value reported when the database_state_values() value for the Datastore is :not_found.

• :not_updated - The Datastore database exists and has been initialized, but does not have the most recent migrations available applied per the migrations management table.

• :ready - The migrations are fully up-to-date and the Datastore is ready to serve the application as needed.

@type timex_shift_options() :: [
  microseconds: integer(),
  seconds: integer(),
  days: integer(),
  months: integer()
]

Options which are expected by the Timex library.

The MscmpSystDb.DbTypes.Interval struct can be converted into a form which can be consumed by Timex.shift/2 and this type defines the possible return values.

Note that this type should closely match the t:Timex.shift_options types except that we limit it to the types present in the MscmpSystDb.DbTypes.Interval.t/0 data type.