Soft Deletes & Multitenancy

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What is the soft delete pattern and what column is typically used to implement it?

AAdding a deleted_at TIMESTAMPTZ column that is NULL for active records and set to the deletion timestamp for deleted ones

BMoving deleted rows to a separate archive table immediately on delete

CMarking rows with status = 'deleted' and using a CHECK constraint to prevent further updates

DUsing cascading deletes with ON DELETE SET NULL on all child foreign keys

Which index is most efficient for a table with soft deletes, where most queries filter on deleted_at IS NULL?

AA standard B-tree index on deleted_at

BA GIN index on deleted_at

CA partial index: CREATE INDEX ON users (email) WHERE deleted_at IS NULL

DNo index is needed since NULL comparisons are inherently fast

In single-table inheritance (STI), how are multiple entity types (e.g., Employee, Manager, Contractor) stored?

AEach type has its own table with no shared columns

BAll types are stored in one table with a discriminator column (e.g., type) and type-specific columns that are NULL for rows of other types

CA junction table maps each entity row to its attribute set

DEach type inherits columns from a parent table using PostgreSQL table inheritance syntax

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