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

Working with entities

In addition to adding a layer of abstraction above the database system, Hibernate introduces state management to entity objects. This shifts the focus of development from executing SQL statements to managing the state of entities.

States of an entity

In Hibernate, an entity can have one of the following four states:

  • Transient: This is the initial state of an entity after instantiation. It does not have a representation in the database yet, and is not associated with a session.

  • Persistent: An entity that is represented in the database and has an identifier assigned. A persistent entity is tied to a session.

  • Detached: When closing the underlying session, a persistent entity will be detached. It will still exist as an object, but updates to it will not be reflected in the database. It can be reattached to a session later to persist it again.

  • Removed: An object that is scheduled for deletion.

The transitions between the states are triggered by calling various methods on the...

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