constraints-reviewer

约束与引用完整性审查

审查数据库约束、外键和数据完整性规则。

数据库级强制执行

# PROBLEM: Model-only validation (race condition vulnerable)
validates :email, uniqueness: true

# SOLUTION: Database constraint + model validation
add_index :users, :email, unique: true
validates :email, uniqueness: true

防止竞态条件

# PROBLEM: Check-then-insert race condition
def claim_slot
  return false if Slot.where(user_id: user.id).exists?
  Slot.create!(user_id: user.id)
end

# SOLUTION: Database constraint with rescue
def claim_slot
  Slot.create!(user_id: user.id)
rescue ActiveRecord::RecordNotUnique
  false
end

缺失约束检查清单

验证	必需的数据库约束
presence: true	NOT NULL
uniqueness: true	唯一索引
belongs_to	外键
enum	检查约束
numericality: { in: }	检查约束

外键级联

# PROBLEM: Orphaned records on deletion
has_many :comments

# SOLUTION: Dependent handling
has_many :comments, dependent: :destroy  # For callbacks
# OR database-level:
add_foreign_key :comments, :posts, on_delete: :cascade

多态关联

# PROBLEM: No referential integrity for polymorphics
belongs_to :commentable, polymorphic: true

# SOLUTION: Validate type + consider alternatives
ALLOWED_TYPES = %w[Post Article].freeze
validates :commentable_type, inclusion: { in: ALLOWED_TYPES }

# Better: separate tables instead of polymorphic
belongs_to :post, optional: true
belongs_to :article, optional: true
validates :post_id, presence: true, unless: :article_id?

孤立记录检测查询

# Find orphaned comments (missing parent)
Comment.left_joins(:post).where(posts: { id: nil })

# Find missing foreign keys
ActiveRecord::Base.connection.tables.each do |table|
  columns = ActiveRecord::Base.connection.columns(table)
  columns.select { |c| c.name.end_with?('_id') }.each do |col|
    # Check if FK exists
  end
end

审查清单

• 所有 uniqueness 验证都配置了唯一索引吗？
• 所有 presence 验证都配置了 NOT NULL 约束吗？
• 所有 _id 列都有外键吗？
• 是否为删除操作定义了级联规则？
• 多态类型是否经过验证？
• 是否能避免产生孤立记录？

输出格式

## Constraints Review: [PASS/WARN/FAIL]

### Missing Database Constraints
- [model]: [validation without DB enforcement]

### Foreign Key Issues
- [table]: [missing FK on _id column]

### Race Condition Risks
- [code location]: [check-then-insert pattern]

### Orphan Risks
- [association]: [could create orphans]

### Recommendations
1. [Prioritized fixes]