Opaleye Tutorials

Contents:

• Instant Gratification
  • Overview
  • Preliminaries
  • Teaching your table schema to Opaleye
  • Connecting to the Postgresql database
  • Selecting all rows
  • Inserting a row
  • Updating a row
  • Selecting a single row
• Basic DB mappings
  • Overview
  • Creating the DB
  • Strange polymorphic records
  • Different types for read & write
  • Handling NULL and database defaults
  • Different types for read & write - again
  • Wrapping-up
  • Template Haskell expansion
• Advanced DB Mappings
  • Overview
  • SQL for table creation
  • Code that we’ll run through
  • Core mechanism for mapping custom Haskell types to PG types
  • Newtypes for primary keys
  • Mapping ENUMs to Haskell ADTs
  • Handing Postgres Arrays
  • Handling JSONB
  • Making columns read-only
• Selecting rows
• Inserting rows
  • SQL for table creation
  • Inserting rows
  • Getting the ID of a newly inserted row
  • Three functions missing from the Opaleye API
  • Dealing with errors
  • Using a different record-type for INSERTs
• Updating rows
  • SQL for table creation
  • Updating rows
  • Getting the updated rows back from the DB
  • Commentary on Opaleye’s update APIs
  • Multi-table updates (updates with JOINs)