{
  "name": "35_alter_column_multiple",
  "operations": [
    {
      "alter_column": {
        "table": "events",
        "column": "name",
        "name": "event_name",
        "type": "text",
        "default": "'unknown event'",
        "nullable": false,
        "comment": "the full name of the event",
        "unique": {
          "name": "events_event_name_unique"
        },
        "check": {
          "name": "event_name_length",
          "constraint": "length(name) > 3"
        },
        "up": "(SELECT CASE WHEN name IS NULL OR LENGTH(name) <= 3 THEN 'placeholder' ELSE name END)",
        "down": "event_name"
      }
    }
  ]
}