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![1) /** Entity class storing rows of table Coffee */
2) case class CoffeeRow(id: Long, name: Option[String])
3) /** Table description of table coffee. Objects of this class serve as
prototypes for rows in queries. */
4) class Coffee(tag: Tag) extends Table[CoffeeRow](tag, "coffee") {
5) def * = (id, name) <> (CoffeeRow.tupled, CoffeeRow.unapply)
6) val id: Column[Long] = column[Long]("id", O.AutoInc, O.PrimaryKey)
7) val name: Column[Option[String]] = column[Option[String]]("name")
8) }
9) /** Collection-like TableQuery object for table Coffee */
10) lazy val Coffee = new TableQuery(tag => new Coffee(tag))
Example Code for Relation Coffee
05/10/14 Slick – TechTalk #42 12](https://image.slidesharecdn.com/slickthemodernwaytoaccessyour-141005045757-conversion-gate01/75/Slick-the-modern-way-to-access-your-Data-11-2048.jpg)
Uploaded byJochen Huelss
Slick – the modern way to access your Data
This document is a presentation about Slick, a modern database query and access library for Scala. It introduces Slick and its main features like easy database access similar to Scala collections and compile time safety. It covers topics like schema generation, basic queries with filtering, sorting and joins, and advanced queries with aggregations and nested queries. Code examples are provided to demonstrate how to get started with Slick and perform common tasks. The presentation concludes that while Slick provides benefits like usability in Scala and being production ready, its generated queries can lack readability.
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Slick – the modern way to access your Data
- 1. Slick – Themodern Way to query your Data! on Jogja Digital Valley Jochen Hülß 01/10/2014 The answer to life, the universe and everything?
- 2. • M.Sc. inBusiness Information Systems (Mannheim University) • Data Mining & Web Usage Mining • Cloud Technologies • 5 years with SAP (Business Software Vendor) • Business Intelligence • Android Development • Heinz-Nixdorf Fellowship-Program • Venture Capital Investment • Ideabox / Mountain SEA Ventures Bio of Jochen 05/10/14 Slick – TechTalk #42 2
- 3. Prerequisites • Knowabout SQL • MVC Pattern • Collections in programming • Ask directly! Before and after Learning Goals • Explain, what Slick is used for. • Know about the advantages of Slick. • Know the basic commands used for querying in Slick. 05/10/14 Slick – TechTalk #42 3
- 4. Motivation What isSlick all about? 05/10/14 4
- 5. COFFEE ID NAME BUYER SALES SUP_ID (FK) PRICE AMOUNT SUPPLIER COF_ID (FK) ID NAME COUNTRY ID NAME COUNTRY FAV_COFFE_ID (FK) Imagine a simple Database schema… 05/10/14 Slick – TechTalk #42 5
- 6. Browser HTML5 JavaScriptCSS JSON Web Framework View Controller Model Database SQL How can we simplify the Database-Controller connection? … being used for a Web Application 05/10/14 Slick – TechTalk #42 6
- 7. Modern database query& access library for Scala Scala Runtime Scala-Controller Slick-Model SQL PostgreSQL Database As a developer, I want to use Slick! 05/10/14 Slick – TechTalk #42 8
- 8. • Easy •Database access just like Scala collections • Manages your Database sessions via JDBC • Supports plain SQL • Simple setup, many supported databases • Precise • Compile time safety • Query re-use with ease Scala functions • Immutable collections • Stateless Features of Slick Slick makes DB access scalable! 05/10/14 Slick – TechTalk #42 9
- 9. Under the Hood How does it work? 05/10/14 10
- 10. Every DB tablegets its own type classes Generate syntax tree for SQL query computation Slick‘s Lifted Query Processing lifting 05/10/14 Slick – TechTalk #42 11
- 11. 1) /** Entityclass storing rows of table Coffee */ 2) case class CoffeeRow(id: Long, name: Option[String]) 3) /** Table description of table coffee. Objects of this class serve as prototypes for rows in queries. */ 4) class Coffee(tag: Tag) extends Table[CoffeeRow](tag, "coffee") { 5) def * = (id, name) <> (CoffeeRow.tupled, CoffeeRow.unapply) 6) val id: Column[Long] = column[Long]("id", O.AutoInc, O.PrimaryKey) 7) val name: Column[Option[String]] = column[Option[String]]("name") 8) } 9) /** Collection-like TableQuery object for table Coffee */ 10) lazy val Coffee = new TableQuery(tag => new Coffee(tag)) Example Code for Relation Coffee 05/10/14 Slick – TechTalk #42 12
- 12. • Scala >2.10 • Scala Build Tool >0.13 • Add dependencies • Slick >2.0 • Database specific driver • Import database driver Many tutorials available Setup More Info: http://slick.typesafe. com/doc/2.0.1/getti ngstarted.html 05/10/14 Slick – TechTalk #42 13
- 13. Getting started SchemaGeneration, Connection, Data inserts 05/10/14 14
- 14. COFFEE ID NAME BUYER SALES SUP_ID (FK) PRICE AMOUNT SUPPLIER COF_ID (FK) ID NAME COUNTY ID NAME COUNTRY FAV_COFFE_ID (FK) Our sample Database schema 05/10/14 Slick – TechTalk #42 15
- 15. Task 1. SchemaGeneration 2. Connection 3. Data inserts Getting started Tips and Tricks • Use Slick‘s SourceCodeGenerator • Use wrapped connection object • Single or batch (faster) insert possible • ID return only with single 05/10/14 Slick – TechTalk #42 16
- 16. Basic Queries Projection,Filtering, Sorting 05/10/14 17
- 17. Task 1. Projection 1. Result list() 2. Result foreach() 3. Result first() 2. Where 3. Where with LIKE 4. Where with AND / OR 5. Sorting Basic Queries Tips and Tricks • “map()” iterates over collection • Result with “list()” in memory, with “foreach()” only temporary • If attribute is not “NOT NULL” on database use “Option()” • Filter with “===“ • Use “toLowerCase()” with “like()” 05/10/14 Slick – TechTalk #42 18
- 18. Advanced Queries Joins,Aggregates, nested Queries 05/10/14 19
- 19. Task 1. InnerJoin 2. Inner Join with condition 3. Inner Join with foreign key 4. Inner Join with 3 tables 5. Aggregation and nested queries (I) 6. Aggregation and nested queries (II) Advanced Queries Tips and Tricks • For-Loop connects two collections • Where conditions start with “if“ • Slick model provides helper for foreign key relations • “groupBy” new collection with tuples • Aggregation max, min, sum, … • Use queries within other queries 05/10/14 Slick – TechTalk #42 20
- 20. Conclusion Is Slickthe answer to life, the universe and everything?! 05/10/14 21
- 21. + Production +Level of control + Lightweight Thoughts on Slick + Usability in Scala - Generated Queries (readability) ready 05/10/14 Slick – TechTalk #42 22
- 22. • http://slick.typesafe.com/doc/2.0.1/ •https://mackler.org/LearningSlick2/ • “Slick - The Structured Way” from SlideShare • “Brief introduction of Slick” from SlideShare References 05/10/14 Slick – TechTalk #42 23
- 23. Thank you! JogjaDigital Valley Jochen Hülß (jochen@huelss.de) 01/10/2014
Editor's Notes
- #23 + Lightweight + Level of control + Production ready Documentation Generated Queries (readability)