Book Image

Learning PostgreSQL

Book Image

Learning PostgreSQL

Overview of this book

PostgreSQL is one of the most powerful and easy to use database management systems. It supports the most advanced features included in SQL standards. The book starts with the introduction of relational databases with PostegreSQL. It then moves on to covering data definition language (DDL) with emphasis on PostgreSQL and common DDL commands supported by ANSI SQL. You will then learn the data manipulation language (DML), and advanced topics like locking and multi version concurrency control (MVCC). This will give you a very robust background to tune and troubleshoot your application. The book then covers the implementation of data models in the database such as creating tables, setting up integrity constraints, building indexes, defining views and other schema objects. Next, it will give you an overview about the NoSQL capabilities of PostgreSQL along with Hstore, XML, Json and arrays. Finally by the end of the book, you'll learn to use the JDBC driver and manipulate data objects in the Hibernate framework.

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Learning PostgreSQL
Nov, 2015 | 464 pages
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Table of Contents (21 chapters)
Learning PostgreSQL
Learning PostgreSQL
Credits
Credits
About the Authors
About the Authors
About the Reviewers
About the Reviewers
www.PacktPub.com
www.PacktPub.com
Preface
Preface
Free Chapter
1
Relational Databases
Relational Databases
Database management systems
Relational algebra
Data modeling
Summary
2
PostgreSQL in Action
PostgreSQL in Action
An overview of PostgreSQL
PostgreSQL capabilities
Installing PostgreSQL
Summary
3
PostgreSQL Basic Building Blocks
PostgreSQL Basic Building Blocks
Database coding
PostgreSQL objects hierarchy
PostgreSQL high-level object interaction
PostgreSQL database components
Summary
4
PostgreSQL Advanced Building Blocks
PostgreSQL Advanced Building Blocks
Views
Indexes
Functions
PostgreSQL user-defined data types
Triggers and rule systems
Summary
5
SQL Language
SQL Language
SQL fundamentals
Querying the data with the SELECT statement
Changing the data in the database
Summary
6
Advanced Query Writing
Advanced Query Writing
Common table expressions
Window functions
Advanced SQL
Transaction isolation and multiversion concurrency control
Summary
7
Server-Side Programming with PL/pgSQL
Server-Side Programming with PL/pgSQL
Introduction
PostgreSQL function parameters
The PostgreSQL PL/pgSQL control statements
Exception handling
Dynamic SQL
Summary
8
PostgreSQL Security
PostgreSQL Security
Authentication in PostgreSQL
PostgreSQL default access privileges
PostgreSQL security levels
Encrypting data
Summary
9
The PostgreSQL System Catalog and System Administration Functions
The PostgreSQL System Catalog and System Administration Functions
The system catalog
Getting the database cluster and client tools version
Terminating and canceling user sessions
Setting and getting database cluster settings
Getting the database and database object size
Cleaning up the database
Cleaning up data in the database
Managing database locks
Adding missing indexes on foreign keys and altering the default statistic
Getting the views dependency tree
Summary
10
Optimizing Database Performance
Optimizing Database Performance
PostgreSQL configuration tuning
Tuning PostgreSQL queries
Cross column correlation
Table partitioning
Summary
11
Beyond Conventional Data types
Beyond Conventional Data types
PostgreSQL arrays
Hash store
The PostgreSQL JSON data type
A PostgreSQL full text search
Summary
12
Testing
Testing
Unit testing
Schema difference
The interfaces test
PostgreSQL benchmarks
Summary
13
PostgreSQL JDBC
PostgreSQL JDBC
Introduction to JDBC
Connecting to a PostgreSQL database
Issuing a query and processing the results
Function handling
Design considerations
Summary
14
PostgreSQL and Hibernate
PostgreSQL and Hibernate
Introduction to ORM and Hibernate
Installation and configuration
Working with entities
Summary
Index
Index

Setting and getting database cluster settings

The PostgreSQL configuration settings control several aspects of the PostgreSQL cluster. For the administration aspect, one can define the statement time out, number of allowed connections, transaction type—read only or read/write—, and so on. From the development point of view, these settings can help a developer optimize queries.

Getting ready

The following recipe shows how to get and set a certain configuration value.

How to do it…

Getting a value can be done in several ways, such as selecting the value from the pg_settings catalog view, browsing the postgresql.conf file, or using the following function and statement:

car_portal=# SELECT current_setting('work_mem');
 current_setting
-----------------
 4MB
(1 row)

car_portal=# show work_mem;
 work_mem
----------
 4MB
(1  row)

In order to change a certain configuration value, one could use the set_config(settin_name, setting_value, scope) function, as follows:

car_portal=# SELECT set_config('work_mem...
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