Clear ORM
  • Welcome to Clear
  • Introduction
    • Setup
  • Model
    • Defining your model
      • Describing your columns
      • Primary Keys
      • Converters
    • Associations
      • belongs_to
      • has_many
      • has_many through
      • has_one
    • Lifecycle
      • Persistence
      • Validations
      • Triggers
    • Batchs operations
      • Bulk update
      • Bulk insert & delete
    • Transactions & Save Points
      • Transaction & Savepoints
      • Connection pool
    • Locks
  • Querying
    • The collection object
      • Filter the query
        • Filter the query – The Expression Engine
        • Find, First, Last, Offset, Limit
        • Aggregation
        • Ordering & Group by
      • Fetching the query
        • Each and Fetch
        • Cursored fetching
        • Model extra attributes
      • Joins
      • Eager Loading
      • Window and CTE
      • Scopes
    • Writing low-level SQL
      • Select Clause
      • Insert Clause
      • Delete Clause
  • Migrations
    • Manage migrations
    • Call migration script
    • Migration CLI
  • Additional and advanced features
    • JSONB
    • Symbol vs String
    • Enums
    • BCrypt
    • Full Text Search
    • Handling multi-connection
  • Other resources
    • API Documentation
    • Inline documentation
    • Github repository
    • Credits
    • Benchmark
Powered by GitBook
On this page
  1. Model

Locks

PreviousConnection poolNextThe collection object

Last updated 5 years ago

Model lock

You can use lock using with_lock method on query collection:

Clear::SQL.transaction do
    # SELECT * FROM users WHERE organization = 'Crystal Lang' FOR UPDATE
    User.where(organization: "Crystal Lang").with_lock.each do |user|
        # Do something with your users
    end
end

with_lock offers optional parameters (default: "FOR UPDATE"), to setup the lock options you want (ex: with_lock("FOR UPDATE SKIP LOCKED"))

See PostgreSQL .

Lock work only inside transaction. Without transaction block, the call might fail.

deep explanation about locking here