How to represent class table inheritance (current DBMS-specific way please)?
Ultimately, I implemented ypercube's suggestion from comments:


  The "type" column can be defined as a computed (but constant) column in SQL-Server. I think it has to be PERSISTED though so it can participate in the Foreign Key constraint.


This worked well both for performance and compatibility with with my tools (Entity Framework &lt;= 6.0):

CREATE TABLE [dbo].[Account](
    [Id] [int] IDENTITY(1000,1) NOT NULL PRIMARY KEY CLUSTERED,
    [CommunityRole] [int] NOT NULL,
    [FirstName] [nvarchar](50) NOT NULL,
    [LastName] [nvarchar](50) NOT NULL,
CONSTRAINT [UX_Derived_Relation] UNIQUE ([Id], [CommunityRole]))

CREATE TABLE [dbo].[Recruiter](
    [Id] [int] NOT NULL PRIMARY KEY CLUSTERED,
    [CommunityRole]  AS ((1)) PERSISTED NOT NULL,
    [RecruiterSpecificValue]  [int] NOT NULL,
FOREIGN KEY ([Id], [CommunityRole]) REFERENCES Account([Id], [CommunityRole]))

CREATE TABLE [dbo].[Candidate](
    [Id] [int] NOT NULL PRIMARY KEY CLUSTERED,
    [CommunityRole]  AS ((2)) PERSISTED NOT NULL,
    [CandidateSpecificValue]  [int] NOT NULL,
FOREIGN KEY ([Id], [CommunityRole]) REFERENCES Account([Id], [CommunityRole]))


This mapped well to my implementation of multiple discrete account types, Recruiter and Candidate, on my Job Board.