PostgreSQL UDF Example

This repository contains an example of a C User-Defined Function (UDF) for PostgreSQL. The UDF takes a string as input and returns a string as output.

Description

• string_udf.c: The C source file for the UDF.
• Makefile: The makefile to compile the UDF into a shared library.
• string_udf--1.0.sql: The SQL script to create the UDF in PostgreSQL.
• string_udf.control: The control file for the PostgreSQL extension.
• Dockerfile: The Dockerfile to build an image with PostgreSQL and compile the UDF.

Instructions to Compile and Use the UDF

Prerequisites

• PostgreSQL installed and running.
• GCC compiler and Make utility installed.

Step 1: Compile the UDF

1. Create the Shared Library: Place string_udf.c, Makefile, string_udf--1.0.sql, and string_udf.control in the same directory. Run the following command to compile the UDF:

   make
   sudo make install

Step 2: Load the UDF in PostgreSQL

1. Connect to PostgreSQL Database: Use psql or another PostgreSQL client to connect to your PostgreSQL database.

2. Create the UDF: Execute the following SQL command to create the UDF:

   CREATE EXTENSION string_udf;

Step 3: Test the UDF

1. Test the UDF: Verify that your UDF is working by calling the function in SQL. Run:

   SELECT string_udf('Hello, World!');

   This should return Hello, World! if the UDF is functioning correctly.

License

This project is licensed under the MIT License - see the LICENSE file for details.