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Learn PostgreSQL

You're reading from   Learn PostgreSQL Build and manage high-performance database solutions using PostgreSQL 12 and 13

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Product type Paperback
Published in Oct 2020
Publisher Packt
ISBN-13 9781838985288
Length 650 pages
Edition 1st Edition
Languages
Concepts
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Authors (2):
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Enrico Pirozzi Enrico Pirozzi
Author Profile Icon Enrico Pirozzi
Enrico Pirozzi
Luca Ferrari Luca Ferrari
Author Profile Icon Luca Ferrari
Luca Ferrari
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Toc

Table of Contents (27) Chapters Close

Preface 1. Section 1: Getting Started
2. Introduction to PostgreSQL FREE CHAPTER 3. Getting to Know Your Cluster 4. Managing Users and Connections 5. Section 2: Interacting with the Database
6. Basic Statements 7. Advanced Statements 8. Window Functions 9. Server-Side Programming 10. Triggers and Rules 11. Partitioning 12. Section 3: Administering the Cluster
13. Users, Roles, and Database Security 14. Transactions, MVCC, WALs, and Checkpoints 15. Extending the Database - the Extension Ecosystem 16. Indexes and Performance Optimization 17. Logging and Auditing 18. Backup and Restore 19. Configuration and Monitoring 20. Section 4: Replication
21. Physical Replication 22. Logical Replication 23. Section 5: The PostegreSQL Ecosystem
24. Useful Tools and Extensions 25. Toward PostgreSQL 13 26. Other Books You May Enjoy

Exploring functions and languages

PostgreSQL is capable of executing server-side code. There are many ways to provide PostgreSQL with the code to be executed. For example, the user can create functions in different programming languages. The main languages ​​supported by PostgreSQL are as follows:

  • SQL
  • PL/pgSQL
  • C

These listed languages are the built-in languages; there are also other languages that PostgreSQL can manage, but before using them, we need to install them on our system. Some of these other supported languages ​​are as follows:

  • PL/Python
  • PL/Perl
  • PL/tcl
  • PL/Java

In this section, we'll talk about SQL and PL/pgSQL functions.

Functions

The command structure with which a function is defined is as follows:

CREATE FUNCTION function_name(p1 type, p2 type,p3 type, ....., pn type)
RETURNS type AS
BEGIN
-- function logic
END;
LANGUAGE language_name

The following steps always apply for any type of function we want to create:

  1. Specify the name of the function...
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