The step in the ALTER TABLE … ADD CONSTRAINT statement where an optional index can be specified to enforce the constraint.

Referencing XYZ*Step types directly from client code

It is usually not recommended to reference any XYZ*Step types directly from client code, or assign them to local variables. When writing dynamic SQL, creating a statement's components dynamically, and passing them to the DSL API statically is usually a better choice. See the manual's section about dynamic SQL for details: https://www.jooq.org/doc/latest/manual/sql-building/dynamic-sql.

Drawbacks of referencing the XYZ*Step types directly:

• They're operating on mutable implementations (as of jOOQ 3.x)
• They're less composable and not easy to get right when dynamic SQL gets complex
• They're less readable
• They might have binary incompatible changes between minor releases