---
title: Deny self-registration check
summary: Reads and maintains the external-user deny list that blocks specific self-registration combinations.
status: draft
owner: SAIF Doc Gen
last_reviewed: 2026-07-30
library: SAIF.Business.External.Users
reference_type: package
operation_id: OP-EU-02
trigger: Registration validators or administrators query or save `clsUserDenySelfRegistration` rows.
---

# Deny self-registration check

This operation manages the `EXT_USER_DENY_SELF_REG` block list. Registration validators call it to determine whether a user-type and source-system group combination is allowed to self-register, and administration flows use the same object model to insert, update, or delete deny-list rows.

| Field | Value |
| --- | --- |
| **Operation ID** | OP-EU-02 |
| **Trigger** | Registration validation or deny-list maintenance request |
| **Inputs** | User-type code, source-system group ID, customer-requested flag, reason text |
| **Outputs** | Matching deny-list row(s) or persisted `EXT_USER_DENY_SELF_REG` change |
| **Primary components** | `clsUserDenySelfRegistration.GetUserDenySelfRegistration`, `clsUserDenySelfRegistrationCollection.GetUserDenySelfRegistrations` |
| **Entry point** | `Business\SAIF.Business.External.Users\clsUserDenySelfRegistration.vb` |

## Steps

1. **Build the lookup key from the registration context.** Callers supply the external-user type code and the customer-group identifier that represents the group being registered.
2. **Retrieve an existing deny-list row when the exact pair is needed.** `GetUserDenySelfRegistration` reads the row keyed by `CUSTOMER_GROUP_ID` and `EXT_USER_TYPE_CODE` ([SQL-027](../sql/SQL-027-saif-business-external-users.md), [EXT_USER_DENY_SELF_REG](../database-tables.md#ext_user_deny_self_reg)).
3. **Retrieve all matching rows for validation scenarios.** `GetUserDenySelfRegistrations` runs the same keyed filter as a collection load so registration validators can test `Count > 0` ([BR-EU-02](../business-rules.md#br-eu-02-deny-self-registration-block-list), [SQL-027](../sql/SQL-027-saif-business-external-users.md), [EXT_USER_DENY_SELF_REG](../database-tables.md#ext_user_deny_self_reg)).
4. **Use the result to block registration when a row exists.** `clsNewUserArgs` calls this collection helper for agency, provider, policyholder, and injured-worker registrations; any returned row causes the validator to return `False` and leave an error message on the caller ([BR-EU-02](../business-rules.md#br-eu-02-deny-self-registration-block-list)).
5. **Insert a new deny-list row when administration adds a block.** `BeforeInsert` stamps create/update metadata and inserts the user type, group ID, customer-requested flag, and reason text ([SQL-007](../sql/SQL-007-saif-business-external-users.md), [EXT_USER_DENY_SELF_REG](../database-tables.md#ext_user_deny_self_reg)).
6. **Update an existing row with optimistic concurrency.** `BeforeUpdate` rewrites the same fields and increments `UPDATE_NUM`; a zero-row result surfaces as a DB-contention error ([BR-EU-05](../business-rules.md#br-eu-05-optimistic-concurrency-via-update_num), [SQL-048](../sql/SQL-048-saif-business-external-users.md), [EXT_USER_DENY_SELF_REG](../database-tables.md#ext_user_deny_self_reg)).
7. **Delete a deny-list row when the block is removed.** `BeforeDelete` deletes by the same composite key ([SQL-054](../sql/SQL-054-saif-business-external-users.md), [EXT_USER_DENY_SELF_REG](../database-tables.md#ext_user_deny_self_reg)).

## Process flow

The following diagram visualizes this operation's control flow.

```mermaid
flowchart TD
    Start([Registration or admin request]) --> Lookup[Load deny-list rows for type and group]
    Lookup --> Match{Match found?}
    Match -->|Yes| Block([Registration blocked or row opened for maintenance])
    Match -->|No| Allow([Registration may continue or admin may add a row])
    Allow --> Save{Persist change?}
    Save -->|Insert or update| Write[Write deny-list row]
    Save -->|Delete| Delete[Remove deny-list row]
    Write --> Done([Return persisted result])
    Delete --> Done
    Block --> Done
```

## Failure and edge-case behavior

- The composite key means one deny-list row governs one user-type and customer-group combination.
- Updates and deletes can fail with DB-contention messaging when another session changed the same row first ([BR-EU-05](../business-rules.md#br-eu-05-optimistic-concurrency-via-update_num)).
- Registration callers treat any matching row as a hard block; there is no partial-warning path in the traced code.

## Related documentation
- [Operations and processes](../operations-processes.md)
- [Business rules](../business-rules.md)
- [SQL catalog](../sql/index.md)
- [Database tables](../database-tables.md)

## Sources
- `Business\SAIF.Business.External.Users\clsUserDenySelfRegistration.vb`
- `Business\SAIF.Business.External.Users\clsNewUserArgs.vb`