Book Image

PostgreSQL Development Essentials

By : Manpreet Kaur, Baji Shaik
Book Image

PostgreSQL Development Essentials

By: Manpreet Kaur, Baji Shaik

Overview of this book

PostgreSQL is the most advanced open source database in the world. It is easy to install, configure, and maintain by following the documentation; however, it’s difficult to develop applications using programming languages and design databases accordingly. This book is what you need to get the most out of PostgreSQL You will begin with advanced SQL topics such as views, materialized views, and cursors, and learn about performing data type conversions. You will then perform trigger operations and use trigger functions in PostgreSQL. Next we walk through data modeling, normalization concepts, and the effect of transactions and locking on the database. The next half of the book covers the types of indexes, constrains, and the concepts of table partitioning, as well as the different mechanisms and approaches available to write efficient queries or code. Later, we explore PostgreSQL Extensions and Large Object Support in PostgreSQL. Finally, you will perform database operations in PostgreSQL using PHP and Java. By the end of this book, you will have mastered all the aspects of PostgreSQL development. You will be able to build efficient enterprise-grade applications with PostgreSQL by making use of these concepts
Table of Contents (17 chapters)
PostgreSQL Development Essentials
About the Authors
About the Reviewers

Using binary large objects

What if someone wants to store a picture, Word document, or PDF, in a database? For this, PostgreSQL has a large object facility that provides stream-style access to user data, which is stored in a special large-object structure. Streaming access is useful when you are working with data values that are too large to manipulate conveniently as a whole.

The large object implementation breaks large objects into chunks and stores them in rows in the database. A B-tree index guarantees fast searches for the correct chunk number when doing random-access reads and writes.

How do we implement it? As this book is intended to teach you the basics, let's look at how to create/implement large objects:

Creating a large object

You can use the lo_creat function to create a large object. The syntax is as follows:

Oid lo_creat(PGconn *conn, int mode);

The return value is Oid.

Here's an example:

inv_oid = lo_creat(conn, INV_READ|INV_WRITE);

The Oid lo_create(PGconn *conn, Oid lobjId)...