Building Grails applications with PostgreSQL
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The document outlines a presentation on building Grails applications with PostgreSQL, conducted by Brent Baxter and Ken Rimple. It provides an overview of the Grails framework, highlights Groovy's dynamic features, and details Grails' object-relational mapping (GORM) capabilities along with PostgreSQL integration. Various Grails components and their configurations are discussed, in addition to resources for further learning and community engagement.
![Benefits of Groovy
• Adds "Convention over Configuration"
‣ Groovy beans are VERY simple
‣ Assumes methods are public, member
variables are private
‣ Constructors not required
‣ Easy collections – Use the [ ] syntax for lists
and maps
PostgreSQL East - March 25, 2010
Tuesday, March 30, 2010](https://image.slidesharecdn.com/pgeast2010grailswithpostgresql-101004161824-phpapp01/85/Building-Grails-applications-with-PostgreSQL-7-320.jpg)
![Constructors and Lists
// Groovy provides constructors for free
def bob = new Person(firstName:'Bob', lastName:'Smith')
def sue = new Person(firstName:'Sue', lastName:'Jones',
birthDate:new Date('8/12/1974'))
// ArrayLists are simple
def persons = [ new Person(firstName:‘Bob’),
new Person(firstName:‘Sue’)]
persons += new Person(firstName:‘John’)
PostgreSQL East - March 25, 2010
Tuesday, March 30, 2010](https://image.slidesharecdn.com/pgeast2010grailswithpostgresql-101004161824-phpapp01/85/Building-Grails-applications-with-PostgreSQL-11-320.jpg)
![Groovy SQL Support
// Using JDBC
def sql = Sql.newInstance(url, usr, pwd, driver)
sql.execute(“insert into table values ($foo, $bar)”)
sql.execute(“insert into table values (?,?)”, [a,b])
sql.eachRow(“select * from USER”) {println it.name}
def list = sql.rows(“select * from USER”)
PostgreSQL East - March 25, 2010
Tuesday, March 30, 2010](https://image.slidesharecdn.com/pgeast2010grailswithpostgresql-101004161824-phpapp01/85/Building-Grails-applications-with-PostgreSQL-12-320.jpg)
![One to many relationship
• Customer 'owns' accounts (cascade deletes, updates, saves)
class Customer {
class Account {
String firstName
static belongsTo =
String lastName
[customer:Customer]
...
String accountNumber
static hasMany = [accounts:Account]
}
}
// arbitrary but working example... flush for testing only...
def customer = new Customer(firstName: "Dude", lastName: "WheresMyCar")
def account = new Account(accountNumber:"1234", customer:customer)
customer.accounts = [account]
def result = customer.save(flush:true)
def account2 = Account.findById(account.id)
println account2.customer
def customer2 = Customer.findById(customer.id)
println customer2.accounts
PostgreSQL East - March 25, 2010
Tuesday, March 30, 2010](https://image.slidesharecdn.com/pgeast2010grailswithpostgresql-101004161824-phpapp01/85/Building-Grails-applications-with-PostgreSQL-29-320.jpg)
Building Grails applications with PostgreSQL
- 1. Building Grails Applications with PostgreSQL Brent Baxter and Ken Rimple PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 2. About Brent and Ken • Brent Baxter: [email protected] ‣ Consultant and Applications Architect ‣ Grails, Java, and Spring developer • Ken Rimple: [email protected] ‣ Head of Education Services ‣ Host, Chariot TechCast: http://techcast.chariotsolutions.com PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 3. About Chariot Solutions • Java and Open Source solutions provider • Chariot Solutions Education Services ‣ Groovy and Grails training and mentoring • Chariot Solutions Consulting ‣ Development and consulting services • http://www.chariotsolutions.com PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 4. Goals • Provide a basic overview of the Grails framework - with a dash of Groovy • Review some of the features of Grails Object Relational Modeling (GORM) • Demonstrate Grails with PostgreSQL PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 5. Introduction to Groovy PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 6. Groovy • A dynamic language built for the Java Virtual Machine ‣ Compiles to native ByteCode ‣ Can inherit Groovy classes from Java classes (and vice versa) ‣ Native access to any Java library PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 7. Benefits of Groovy • Adds "Convention over Configuration" ‣ Groovy beans are VERY simple ‣ Assumes methods are public, member variables are private ‣ Constructors not required ‣ Easy collections – Use the [ ] syntax for lists and maps PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 8. A Sampling of Groovy APIs • xml – Powerful XML • builders – a set of Parsing, Creation repetitive building tasks can be automated using various • gsql – Simplified JDBC API Groovy Builders • Groovy Testing– simple • Swing – the Groovy testing API, mocking with SwingBuilder makes UI closures, etc... easy. Also Griffon is a Groovy-based MVC • Collections – lists, maps framework for Swing (like Grails for Web) and ranges PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 9. Java Person Class public class Person { private String firstName; private String lastName; private Date birthDate; public Person(String firstName, String lastName, Date birthDate) { ... } public void setFirstName() { ... } public String getFirstName() { ... } // etc... } PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 10. Groovy Person Class class Person { String lastName String firstName Date birthDate } PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 11. Constructors and Lists // Groovy provides constructors for free def bob = new Person(firstName:'Bob', lastName:'Smith') def sue = new Person(firstName:'Sue', lastName:'Jones', birthDate:new Date('8/12/1974')) // ArrayLists are simple def persons = [ new Person(firstName:‘Bob’), new Person(firstName:‘Sue’)] persons += new Person(firstName:‘John’) PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 12. Groovy SQL Support // Using JDBC def sql = Sql.newInstance(url, usr, pwd, driver) sql.execute(“insert into table values ($foo, $bar)”) sql.execute(“insert into table values (?,?)”, [a,b]) sql.eachRow(“select * from USER”) {println it.name} def list = sql.rows(“select * from USER”) PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 13. Introduction to Grails PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 14. Grails Framework • A web application framework ‣ Three-tiered Model View Controller (MVC) • Convention based ‣ Sensible default configuration or use any of a number of simple DSLs • Extendable with a rich set of plug-ins PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 15. Grails Is Groovy • Leverages the Groovy programing language ‣ Groovy Services and Beans • Configuration DSLs ‣ Logging, data source configuration, dependency resolution, ... • Web tier Groovy Server Pages (GSP) PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 16. Grails Is Java • Framework backed by best of breed industry standards ‣ Spring, Hibernate, SiteMesh, Web Flow, etc. • Leverage any Java library, access from Groovy or Java classes • Can be deployed as a Java web application (WAR) to any Servlet container PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 17. Grails Technology Stack Grails Standard SiteMesh Spring Hibernate Groovy Libraries Java API Java Platform (JVM) PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 18. Key Grails Components • Domain Class - A class representing an object in your domain (database table) • Controller - A class that operates on URLs submitted to the web site • View - A Groovy Server Page (GSP) designed to render the content based on a specific request PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 19. Domain Driven Design with Grails • Focus on the complexities of the domain first • Create domain objects and their relationships first • Dynamically 'scaffold' controllers and views for each domain class, validate domain objects and relationships • When ready, finish by generating or coding all views, controllers, and tests PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 20. Grails Scaffolding • Dynamically generated views based on default templates • No need to define a page before completing the data model // Domain // Dynamic Scaffold Controller class Person { class PersonController { String firstName def scaffold = true String lastName } Date birthDate } PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 21. More than a web framework... • Eases development of every tier ‣ Integrated Groovy build system ‣ Integrated Groovy unit and integration test mechanism ‣ Simple ORM based on Hibernate ‣ Extensible plug-in system built on Spring ‣ Also simplifies Web MVC PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 22. Grails Object Relational Mapping (GORM) PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 23. GORM • Grails Object Relational Mapping API ‣ Uses domain classes written in Groovy ‣ Injects methods into domain classes for load, save, update, and query data ‣ Backed by Hibernate and Spring ‣ Write Hibernate objects without all of the messy XML! PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 24. GORM Benefits • Write your domain classes as POGOs • Define validation via constraints • Define relationships via simple belongsTo, hasMany mappings • Easy to test framework, can use grails console or grails shell, even integration tests • Finders make it easy to locate data PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 25. Grails Domain Classes • Created with create-domain-class • Simple Groovy Beans ‣ Each member variable represents a column in a table ‣ Implied version, primary key fields ‣ Can define relationships with other domains, validation constraints PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 26. Connecting to PostgreSQL • Grails defines database connections for various environments (Development, Test, Production) • Steps to configure your database ‣ Install your database driver ‣ Modify grails-app/config/DataSource.groovy ‣ Boot grails with grails run-app PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 27. Defining Constraints class Customer { • Checked automatically static constraints = { when saved firstName(maxLength: 15, blank: false) lastName(maxLength: 20, blank: false) or when registrationDate(nullable: false) validate() is preferredCustomer(default: true) called awardsBalance(range: 0.0..5000.0) } String firstName • Tip: scaffold String lastName configuration Date registrationDate Boolean preferredCustomer follows BigDecimal awardsBalance constraint } order for field order PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 28. Entity Relationships • Grails supports all Hibernate relation mappings ‣ One to One ‣ One to Many ‣ Many to Many ‣ Parent/Child (Inheritence) PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 29. One to many relationship • Customer 'owns' accounts (cascade deletes, updates, saves) class Customer { class Account { String firstName static belongsTo = String lastName [customer:Customer] ... String accountNumber static hasMany = [accounts:Account] } } // arbitrary but working example... flush for testing only... def customer = new Customer(firstName: "Dude", lastName: "WheresMyCar") def account = new Account(accountNumber:"1234", customer:customer) customer.accounts = [account] def result = customer.save(flush:true) def account2 = Account.findById(account.id) println account2.customer def customer2 = Customer.findById(customer.id) println customer2.accounts PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 30. Physical DB Settings - mapping • Changing the table, versioning on/off, column mappings, indexing, multi-column-index, etc... class Person { String firstName String address static mapping = { table 'people' version false id column:'person_id' firstName column:'First_Name', index:'Name_Idx' address column:'Address', index:'Name_Idx, Address_Index' } } PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 31. Stored Procedures • Several approaches ‣ Spring's JdbcTemplate ‣ Spring's StoredProcedure class ‣ Spring's SqlFunction ‣ Groovy SQL • Demonstration PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 32. Where to find the code • Hit our GitHub repository (you can just ask to download the files) • GitHub repo for our samples ‣ github.com/krimple/Grails-Demos- PostgreSQL-East-2010.git PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 33. Groovy and Grails Resources • Grails Web Site ‣ http://www.grails.org • Grails User Email List ‣ http://n4.nabble.com/Grails-f1312388.html • Groovy Web Site ‣ http://groovy.codehaus.org/ PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 34. Free InfoQ E-Book • Getting Started with Grails, Second Edition ‣ Scott Davis ‣ Jason Rudolph • http://www.infoq.com/ minibooks/grails-getting- started PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 35. Regional User Groups • Philadelphia Groovy and Grails User Group ‣ http://phillygroovy.org ‣ Meet-up April 8 as part of Philly ETE • Philadelphia Spring User Group ‣ http://phillyspring.ning.com/ PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010
- 36. Thank you! Questions ... ? PostgreSQL East - March 25, 2010 Tuesday, March 30, 2010