multiple different types... – Polymorphic Variable The challenge is the variable • ...or the provision of a single interface to entities of different types – Polymorphic Invokable • Polymorphism is type Polymorphism ## Polymorphic Variables • Base class pointer to derived class – Virtual functions are not bad! • Standard Template Library - std::any - std::variant - std::tuple ## Polymorphic Invokables outputs) { ??? What is the polymorphic type for the vector? What is the polymorphic invocation? ## std::any ## A Type That Can Contain Any Type Challenging as a Polymorphic Variable ## std::any ## •

Variable Number of Arguments 392 Example: Using Default Argument Values 392 Example: Using Polymorphic Data Types 393 Example: Anonymous Block 394 References 394 PL/Python Language 395 Time Zones 1416 Interval Input 1418 Interval Output 1420 Pseudo-Types 1420 Pseudo-Types 0 Polymorphic Types 1421 Table Value Expressions 1422 Text Search Data Types 1422 Text Search Data Types caches a separate query plan for each combination of actual argument types in which you invoke a polymorphic function to ensure that data type differences do not cause unexpected failures. Refer to the PostgreSQL

‘per’, ‘item’]) Transforms a one dimensional array into rows. Returns a set of anyelement, a polymorphic pseudo-type in PostgreSQL. 785 Working with JSON Data 785 About JSON Data 786 About Unicode Characters Using a Variable Number of Arguments 951 Example: Using Default Argument Values 952 Example: Using Polymorphic Data Types 953 Example: Anonymous Block 954 References 954 PL/Python Language 954 About Greenplum Date/Time Output 1680 Time Zones 1681 Interval Input 1682 Interval Output 1684 Pseudo-Types 1685 Polymorphic Types 1686 Table Value Expressions 1687 Text Search Data Types 1687 tsvector 1687 tsquery 1689

Using a Variable Number of Arguments 947 Example: Using Default Argument Values 947 Example: Using Polymorphic Data Types 948 Example: Anonymous Block 949 References 949 PL/Python Language 950 About Greenplum Interval Output 1681 VMware Tanzu Greenplum 6 Documentation VMware, Inc. 96 Pseudo-Types 1681 Polymorphic Types 1682 Table Value Expressions 1683 Text Search Data Types 1684 tsvector 1684 tsquery 1685 Functions The developer of a foreign-data wrapper must implement an SQL-invokable handler function, and optionally an SQL-invokable validator function. Both functions must be written in a compiled language

Using a Variable Number of Arguments 982 Example: Using Default Argument Values 983 Example: Using Polymorphic Data Types 984 Example: Anonymous Block 984 References 985 PL/Python Language 985 About Greenplum Date/Time Output 1727 Time Zones 1727 Interval Input 1729 Interval Output 1731 Pseudo-Types 1732 Polymorphic Types 1732 Table Value Expressions 1733 Text Search Data Types 1734 tsvector 1734 tsquery 1735 Functions The developer of a foreign-data wrapper must implement an SQL-invokable handler function, and optionally an SQL-invokable validator function. Both functions must be written in a compiled language

Variable Number of Arguments 995 Example: Using Default Argument Values 996 Example: Using Polymorphic Data Types 996 Example: Anonymous Block 997 References 998 PL/Python Language 998 About Output 1753 Time Zones 1754 Interval Input 1755 Interval Output 1757 Pseudo-Types 1758 Polymorphic Types 1758 Table Value Expressions 1759 Text Search Data Types 1760 tsvector 1760 tsquery Functions The developer of a foreign-data wrapper must implement an SQL-invokable handler function, and optionally an SQL-invokable validator function. Both functions must be written in a compiled language

caches a separate query plan for each combination of actual argument types in which you invoke a polymorphic function to ensure that data type differences do not cause unexpected failures. Refer to the PostgreSQL as the users.user_id column: my_userid users.user_id%TYPE; %TYPE is particularly valuable in polymorphic functions, since the data types needed for internal variables may change from one call to the next also use the = sign in place of the keyword DEFAULT. ## Example: Using Polymorphic Data Types PL/pgSQL supports the polymorphic anyelement, anyarray, anyenum, and anynonarray types. Using these types

thing satisfying a function signature – via std::function/std::move_only_function/std::invoke • Invokable on any callable target • Versatile ## Dependency Injection via type erasure using CalculateYield function satisfying a function signature – via std::function/std::move_only_function/std::invoke • Invokable on any callable target • Versatile ## Drawbacks • Can handle only the one method being substituted

Composite Types ..... 630 34.2.3. Domains ..... 631 34.2.4. Pseudo-Types ..... 631 34.2.5. Polymorphic Types ..... 631 34.3. User-Defined Functions ..... 632 34.4. Query Language (SQL) Functions Functions as Table Sources ..... 638 34.4.5. SQL Functions Returning Sets ..... 639 34.4.6. Polymorphic SQL Functions ..... 640 34.5. Function Overloading ..... 641 34.6. Function Volatility Categories Returning Rows (Composite Types) ..... 659 34.9.10. Returning Sets ..... 661 34.9.11. Polymorphic Arguments and Return Types ..... 665 34.9.12. Shared Memory and LWLocks ..... 666 34.10

Composite Types ..... 740 34.2.3. Domains ..... 740 34.2.4. Pseudo-Types ..... 740 34.2.5. Polymorphic Types ..... 740 34.3. User-Defined Functions ..... 741 34.4. Query Language (SQL) Functions Functions Returning Sets .....750 34.4.8. SQL Functions Returning TABLE .....752 34.4.9. Polymorphic SQL Functions .....752 34.5. Function Overloading .....754 34.6. Function Volatility Categories 9. Returning Rows (Composite Types) .....773 34.9.10. Returning Sets .....774 34.9.11. Polymorphic Arguments and Return Types .....779 34.9.12. Shared Memory and LWLocks .....781 34.10.