Mapping Columns and Expressions

The following sections discuss how table columns and SQL expressions are mapped to individual object attributes.

• Mapping Table Columns
  • Naming Columns Distinctly from Attribute Names
  • Automating Column Naming Schemes from Reflected Tables
  • Using column_property for column level options
    • column_property()
  • Mapping to an Explicit Set of Primary Key Columns
  • Mapping a Subset of Table Columns
• SQL Expressions as Mapped Attributes
  • Using a Hybrid
  • Using column_property
    • Composing from Column Properties at Mapping Time
  • Using a plain descriptor
  • Query-time SQL expressions as mapped attributes
    • Using with_expression() with UNIONs, other subqueries
• Changing Attribute Behavior
  • Simple Validators
    • validates()
  • Using Custom Datatypes at the Core Level
  • Using Descriptors and Hybrids
  • Synonyms
    • synonym()
  • Operator Customization
• Composite Column Types
  • composite()
  • Tracking In-Place Mutations on Composites
  • Redefining Comparison Operations for Composites
  • Nesting Composites