feat(lib/columns): support retrieving generated columns

Author: soedirgo

src/lib/sql/columns.sql

@@ -33,6 +33,7 @@ SELECT
     WHEN 'd' THEN 'BY DEFAULT'
     ELSE NULL
   END AS identity_generation,
+  a.attgenerated IN ('s') AS is_generated,
   NOT (
     a.attnotnull
     OR t.typtype = 'd' AND t.typnotnull

src/lib/types.ts

@@ -33,6 +33,7 @@ export const postgresColumnSchema = Type.Object({
     Type.Literal('BY DEFAULT'),
     Type.Null(),
   ]),
+  is_generated: Type.Boolean(),
   is_nullable: Type.Boolean(),
   is_updatable: Type.Boolean(),
   is_unique: Type.Boolean(),