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PostgreSQL 8.2.23 Documentation
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Chapter 33. Extending SQL

Table of Contents

33.1. How Extensibility Works

33.2. The PostgreSQL Type System

33.2.1. Base Types
33.2.2. Composite Types
33.2.3. Domains
33.2.4. Pseudo-Types
33.2.5. Polymorphic Types

33.3. User-Defined Functions

33.4. Query Language (SQL) Functions

33.4.1. SQL Functions on Base Types
33.4.2. SQL Functions on Composite Types
33.4.3. Functions with Output Parameters
33.4.4. SQL Functions as Table Sources
33.4.5. SQL Functions Returning Sets
33.4.6. Polymorphic SQL Functions

33.5. Function Overloading

33.6. Function Volatility Categories

33.7. Procedural Language Functions

33.8. Internal Functions

33.9. C-Language Functions

33.9.1. Dynamic Loading
33.9.2. Base Types in C-Language Functions
33.9.3. Version 0 Calling Conventions
33.9.4. Version 1 Calling Conventions
33.9.5. Writing Code
33.9.6. Compiling and Linking Dynamically-Loaded Functions
33.9.7. Extension Building Infrastructure
33.9.8. Composite-Type Arguments
33.9.9. Returning Rows (Composite Types)
33.9.10. Returning Sets
33.9.11. Polymorphic Arguments and Return Types
33.9.12. Shared Memory and LWLocks

33.10. User-Defined Aggregates

33.11. User-Defined Types

33.12. User-Defined Operators

33.13. Operator Optimization Information

33.13.1. COMMUTATOR
33.13.2. NEGATOR
33.13.3. RESTRICT
33.13.4. JOIN
33.13.5. HASHES
33.13.6. MERGES (SORT1, SORT2, LTCMP, GTCMP)

33.14. Interfacing Extensions To Indexes

33.14.1. Index Methods and Operator Classes
33.14.2. Index Method Strategies
33.14.3. Index Method Support Routines
33.14.4. An Example
33.14.5. Cross-Data-Type Operator Classes
33.14.6. System Dependencies on Operator Classes
33.14.7. 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 33.3)
aggregates (starting in Section 33.10)
data types (starting in Section 33.11)
operators (starting in Section 33.12)
operator classes for indexes (starting in Section 33.14)

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