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PostgreSQL 9.5.20 Documentation
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Chapter 35. Extending SQL

Table of Contents

35.1. How Extensibility Works

35.2. The PostgreSQL Type System

35.2.1. Base Types
35.2.2. Composite Types
35.2.3. Domains
35.2.4. Pseudo-Types
35.2.5. Polymorphic Types

35.3. User-defined Functions

35.4. Query Language (SQL) Functions

35.4.1. Arguments for SQL Functions
35.4.2. SQL Functions on Base Types
35.4.3. SQL Functions on Composite Types
35.4.4. SQL Functions with Output Parameters
35.4.5. SQL Functions with Variable Numbers of Arguments
35.4.6. SQL Functions with Default Values for Arguments
35.4.7. SQL Functions as Table Sources
35.4.8. SQL Functions Returning Sets
35.4.9. SQL Functions Returning TABLE
35.4.10. Polymorphic SQL Functions
35.4.11. SQL Functions with Collations

35.5. Function Overloading

35.6. Function Volatility Categories

35.7. Procedural Language Functions

35.8. Internal Functions

35.9. C-Language Functions

35.9.1. Dynamic Loading
35.9.2. Base Types in C-Language Functions
35.9.3. Version 0 Calling Conventions
35.9.4. Version 1 Calling Conventions
35.9.5. Writing Code
35.9.6. Compiling and Linking Dynamically-loaded Functions
35.9.7. Composite-type Arguments
35.9.8. Returning Rows (Composite Types)
35.9.9. Returning Sets
35.9.10. Polymorphic Arguments and Return Types
35.9.11. Transform Functions
35.9.12. Shared Memory and LWLocks
35.9.13. Using C++ for Extensibility

35.10. User-defined Aggregates

35.10.1. Moving-Aggregate Mode
35.10.2. Polymorphic and Variadic Aggregates
35.10.3. Ordered-Set Aggregates
35.10.4. Support Functions for Aggregates

35.11. User-defined Types

35.12. User-defined Operators

35.13. Operator Optimization Information

35.13.1. COMMUTATOR
35.13.2. NEGATOR
35.13.3. RESTRICT
35.13.4. JOIN
35.13.5. HASHES
35.13.6. MERGES

35.14. Interfacing Extensions To Indexes

35.14.1. Index Methods and Operator Classes
35.14.2. Index Method Strategies
35.14.3. Index Method Support Routines
35.14.4. An Example
35.14.5. Operator Classes and Operator Families
35.14.6. System Dependencies on Operator Classes
35.14.7. Ordering Operators
35.14.8. Special Features of Operator Classes

35.15. Packaging Related Objects into an Extension

35.15.1. Defining Extension Objects
35.15.2. Extension Files
35.15.3. Extension Relocatability
35.15.4. Extension Configuration Tables
35.15.5. Extension Updates
35.15.6. Extension Example

35.16. Extension Building Infrastructure

In the sections that follow, we will discuss how you can extend the PostgreSQL SQL query language by adding:

functions (starting in Section 35.3)
aggregates (starting in Section 35.10)
data types (starting in Section 35.11)
operators (starting in Section 35.12)
operator classes for indexes (starting in Section 35.14)
packages of related objects (starting in Section 35.15)

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