Relationship Configuration — SQLAlchemy 2.0.0b1 documentation

Relationship Configuration

This section describes the relationship() function and in depth discussion of its usage. For an introduction to relationships, start with the ormtutorial_toplevel and head into orm_tutorial_relationship.

• Basic Relationship Patterns
  • One To Many
    • Configuring Delete Behavior for One to Many
  • Many To One
  • One To One
  • Many To Many
    • Deleting Rows from the Many to Many Table
  • Association Object
• Late-Evaluation of Relationship Arguments
  • Late-Evaluation for a many-to-many relationship
• Adjacency List Relationships
  • Composite Adjacency Lists
  • Self-Referential Query Strategies
  • Configuring Self-Referential Eager Loading
• Linking Relationships with Backref
  • Backref Arguments
  • Setting cascade for backrefs
  • One Way Backrefs
• Configuring how Relationship Joins
  • Handling Multiple Join Paths
  • Specifying Alternate Join Conditions
  • Creating Custom Foreign Conditions
  • Using custom operators in join conditions
  • Custom operators based on SQL functions
  • Overlapping Foreign Keys
  • Non-relational Comparisons / Materialized Path
  • Self-Referential Many-to-Many Relationship
  • Composite “Secondary” Joins
  • Relationship to Aliased Class
    • Using the AliasedClass target in Queries
  • Row-Limited Relationships with Window Functions
  • Building Query-Enabled Properties
• Collection Configuration and Techniques
  • Working with Large Collections
    • Dynamic Relationship Loaders
    • Setting Noload, RaiseLoad
    • Using Passive Deletes
  • Customizing Collection Access
    • Dictionary Collections
  • Custom Collection Implementations
    • Annotating Custom Collections via Decorators
    • Custom Dictionary-Based Collections
    • Instrumentation and Custom Types
  • Collection Internals
• Special Relationship Persistence Patterns
  • Rows that point to themselves / Mutually Dependent Rows
  • Mutable Primary Keys / Update Cascades
    • Simulating limited ON UPDATE CASCADE without foreign key support
• Relationships API