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PostgreSQL 8.4.22 Documentation
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Chapter 34. Extending SQL

Table of Contents

34.1. How Extensibility Works

34.2. The PostgreSQL Type System

34.2.1. Base Types
34.2.2. Composite Types
34.2.3. Domains
34.2.4. Pseudo-Types
34.2.5. Polymorphic Types

34.3. User-Defined Functions

34.4. Query Language (SQL) Functions

34.4.1. SQL Functions on Base Types
34.4.2. SQL Functions on Composite Types
34.4.3. SQL Functions with Output Parameters
34.4.4. SQL Functions with Variable Numbers of Arguments
34.4.5. SQL Functions with Default Values for Arguments
34.4.6. SQL Functions as Table Sources
34.4.7. SQL Functions Returning Sets
34.4.8. SQL Functions Returning TABLE
34.4.9. Polymorphic SQL Functions

34.5. Function Overloading

34.6. Function Volatility Categories

34.7. Procedural Language Functions

34.8. Internal Functions

34.9. C-Language Functions

34.9.1. Dynamic Loading
34.9.2. Base Types in C-Language Functions
34.9.3. Version 0 Calling Conventions
34.9.4. Version 1 Calling Conventions
34.9.5. Writing Code
34.9.6. Compiling and Linking Dynamically-Loaded Functions
34.9.7. Extension Building Infrastructure
34.9.8. Composite-Type Arguments
34.9.9. Returning Rows (Composite Types)
34.9.10. Returning Sets
34.9.11. Polymorphic Arguments and Return Types
34.9.12. Shared Memory and LWLocks

34.10. User-Defined Aggregates

34.11. User-Defined Types

34.12. User-Defined Operators

34.13. Operator Optimization Information

34.13.1. COMMUTATOR
34.13.2. NEGATOR
34.13.3. RESTRICT
34.13.4. JOIN
34.13.5. HASHES
34.13.6. MERGES

34.14. Interfacing Extensions To Indexes

34.14.1. Index Methods and Operator Classes
34.14.2. Index Method Strategies
34.14.3. Index Method Support Routines
34.14.4. An Example
34.14.5. Operator Classes and Operator Families
34.14.6. System Dependencies on Operator Classes
34.14.7. Special Features of Operator Classes

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

functions (starting in Section 34.3)
aggregates (starting in Section 34.10)
data types (starting in Section 34.11)
operators (starting in Section 34.12)
operator classes for indexes (starting in Section 34.14)

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