This document provides an overview of MongoDB and the Morphia object-document mapper for Java. It discusses MongoDB concepts like document storage, indexing, and concurrency model. It then covers Morphia's annotations for mapping Java objects to MongoDB documents, including entity configuration, relationships, and common data access patterns using queries and updates. Code examples are provided for mapping object graphs, querying, and updating documents.

1. MongoDB: ObjStorSol + Des+Map’nYeah, I shortened that… but not to OSSDnM

2. …AppServer - J2EE (JBoss, Resin)Hosted AppServices - Google AppEngineDatastore - Objectify (GAEJ ORM/ODM)MongoDB – Morphia (ODM)Community Developer (and more)How I got here…

3. Basic ExpectationsNo transactions (but atomic updates)Memory mapped data filesDocument storeFast-N-Loose by default (no safe/w/GLE)Indexing order matters; query optimizer helpsOne writer (serialized writes)One JS thread (M/R, $where, group)Many query threads (non-js)BSON everywhere

4. What is the shell?

5. What is it good for?DebuggingTestingAdministrationScripting GlueNot building apps, probably…

6. Shell Demo

7. Single Collection, InheritanceOne – ManyEmbeddedReferenceOn the one -> Array of refsOn the Many -> Add a ref fieldTreesMany – ManyProb. best to store on only one side.Designs

8. { _id : "scotthernandez", name : "Scott Hernandez",desc : "that guy", groups : [ "users", "admins", "fishermen" ]}People - Groups

9. { "_id" : "users", "desc" : "normal users“ },{ "_id" : "fishermen", "desc" : "people who fish“ },{ "_id" : "admins", "privledges" : 2, "desc" : "administrative users“ }Group - People

10. blog =: { text: “I like to swim”, author: “scott”, comments: [ {author:”ralph”, text:”me2”, replies:[ {author:”liz”, text:”doesn’t every1?”} ]}, {author:”jeff”, text:”good to know”} ],ts:Date(…)}Tree

11. Raw MongoDB DriverMap<String, Object> view of objectsRough but dynamicMorphia (type-safe mapper)POJOsAnnotation based (similar to JPA)Syntactic sugar and helpersOthersCode generators, other jvm languagesJava Library Choices

12. BSON PackageTypesEncode/DecodeDBObject (Map<String, Object>)Nested MapsDirectly encoded to binary format (BSON)MongoDB PackageMongoDBObject (BasicDBObject/Builder)DB/DBColletionDBQuery/DBCursorMongoDB Java Driver

13. Data Typesint and longArray/ArrayListStringbyte[] – binDataDouble (IEEE 754 FP)Date (ms since epoch UTC)NullBooleanJavaScript StringRegexObjectId (ts(4)+ host(3) + pid(2)+ incr(3) ) 12-byteBSON Package

14. Morphia: MongoDB MapperMaps POJOType-safeAccess Patterns: DAO/Datastore/RollYourOwnData TypesLow performance overheadJPA likeMany concepts came from Objectify (GAE)

15. Annotations@Entity(“collectionName”)@Id@Transient (not transient)@Indexed(…)@Property(“fieldAlias”)@AlsoLoad({aliases})@Reference@Serialized[@Embedded]

16. Lifecycle Events@PrePersist@PreSave@PostPersist@PreLoad@PostLoadEntityListenersEntityInterceptor

17. Datastore Basicsget(class, id)find(class, […])save(entity, […])delete(query)getCount(query)update/First(query, upOps)findAndModify/Delete(query, upOps)

18. Basic POJO@Entityclass Person { @Id ObjectId name;SexEnum sex;@IndexedInteger height;}

19. QueriesDatastoreds = …Query q = ds.createQuery(Person.class);q.field(“height”).greaterThan(155).limit(5);for(Person p : q.fetch()) print(p);Person me = q.field(“name”).startsWith(“sc”).get();

20. Save whole object graphs (get/save)Update parts (embedded objects)Un/set fieldsPush/pop arrays (lists)Increment numeric fieldsAny combination of the aboveGet/Save or Update

21. Update Operationsset(field, val)unset(field)inc(field, [val])dec(field)add(field, val)addAdd(field, vals)removeFirst/Last(field)removeAll(field, vals)

22. Update existing propsUpdate w/new propsExamples

23. UpdateDatastoreds = …Query q = ds.find(Person.class, “name”, “scott”);UpdateOperationuo = ds.createUpdateOperations(cls)uo.set(“city”, “seattle”).set(“lastUpdated”, new Date());UpdateResults res = ds.update(q, uo);if(res.getUpdatedCount() > 0) //do something?

24. Morphia Relationships Annotations[@Embedded]Load/Save with EntityUpdate@ReferenceStored as DBRef(s)Loaded with EntityNot automatically savedKey<T>Stored as DBRef(s)Just a link, but resolvable by Datastore/Query

25. Or… ScottHernandez@gmail.comQuestions?