banDropNotNull

Diagnostic Category: lint/safety/banDropNotNull

Since: vnext

[!NOTE] This rule is recommended. A diagnostic error will appear when linting your code.

Sources:

• Inspired from: <a href="https://squawkhq.com/docs/ban-drop-not-null" target="_blank"><code>squawk/ban-drop-not-null</code></a>

Description

Dropping a NOT NULL constraint may break existing clients.

Application code or code written in procedural languages like PL/SQL or PL/pgSQL may not expect NULL values for the column that was previously guaranteed to be NOT NULL and therefore may fail to process them correctly.

You can consider using a marker value that represents NULL. Alternatively, create a new table allowing NULL values, copy the data from the old table, and create a view that filters NULL values.

Examples

Invalid

alter table users alter column email drop not null;

code-block.sql:1:1 lint/safety/banDropNotNull ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ! Dropping a NOT NULL constraint may break existing clients.
  
  > 1 │ alter table users alter column email drop not null;
      │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 
  
  i Consider using a marker value that represents NULL. Alternatively, create a new table allowing NULL values, copy the data from the old table, and create a view that filters NULL values.
  

How to configure

{
  "linter": {
    "rules": {
      "safety": {
        "banDropNotNull": "error"
      }
    }
  }
}