Table: Custom_Grouping
Columns
Name	Type	Constraints	Description
custom_grouping_KEY	int	NOT NULL
update__staff_KEY	int	NOT NULL
update_date_utc	datetime	NOT NULL
custom_field_KEY	int	NOT NULL	Key to a Custom Field.
custom_grouping_id	nvarchar (11)	NOT NULL	User defined identifier (unique).
description	nvarchar (250)	NOT NULL	User defined description.
create_date_utc	datetime	NOT NULL
custom_grouping_id_sortable	varchar (48)	NOT NULL	A representation of the custom_grouping_id column that sorts in natural order, meaning that digits are sorted as numbers while non-digits are sorted alphabetically. A trigger keeps this field synchronized with the content of custom_grouping_id.

Primary key
Name	Columns		Description
PK_Custom_Grouping$custom_grouping_KEY	custom_grouping_KEY		CLUSTERED
Unique constraints
Name	Columns		Description
UK_Custom_Grouping$custom_field_KEY$custom_grouping_id	custom_field_KEY, custom_grouping_id
UK_Custom_Grouping$custom_field_KEY$custom_grouping_id_sortable	custom_field_KEY, custom_grouping_id_sortable		An index by the sortable ID is desired, and the algorithm ends up producing unique values.

Foreign keys
Name	Columns	Referenced table	Description
FK_Custom_Grouping__Custom_Field__custom_field_KEY	custom_field_KEY	Custom_Field