Category Archives: Java/Java EE

[2018 oracle code one] graph databases

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Let’s Make Graph Databases Fun agan with Java
Speaker: Otavo Santana & Elder Moraes
Tomitribe & Oracle

For more blog posts, see The Oracle Code One table of contents

Sematics

  • Web 3.0 – More interaction between machines
  • Search JCP. Get JC Penny vs Java Community Process
  • Search Ajax. Get cleaner, technology and soccer team

Relationships

  • Link pieces of data
  • Having metadata on relatioships is useful. (Ex: reason for travel, not just that does travel)

NoSQL (not only SQL)

  • Doesn’t use structure or transactions
  • Five diferent types – key/value, columns, document, graph, hybrid of multiple types
Term Key/value Columns Document Graph
Table Bucket Column Family Collection N/A
Row Key Value pair Column Document Vertex
Column N/a Key/value pair Key/value pair Vertex and edge property

 

  • CAP – consistencyy, availability, fault tolerance
  • Graph – neo4j, infogrpi, sones, hybergraphdb
  • Apache TinkerPop  like JDBC – try to standardize database interaction
    • Can add edge/verfix
    • has()  – like where cause
    • OutE() – edges
    • BothV() – reurn both ends of relationship
    • repeat/times – repeat action mltiple times to go through graph
    • repeat.until – repeat action until condition is true
  • JNoSQL – mapping/communication API. Like  a demo. Maps to Java object

My take: I learned a lot at this session! I really like the comparison of different database types and terms. I also liked the build up of queries and the Noe4J demo

[2018 Oracle Code One] Developer Horror Stories

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Development Horror Stories
Speaker: Roberto Cortez & Oleg Selajev

For more blog posts, see The Oracle Code One table of contents

Stories

  • Broke filter so showed adult videos
  • Deleted inventory and no backups. Had to re-enter all data manually.
  • Units of measure
  • Emails with invalid address so bounced around for hours
  • Deleting a repository instead of a file
  • Used a magic number and it lived on forever..
  • Underpowered servers ad not enough tuning.
  • Off by one error because didn’t account for leap year
  • Recursive SQL statement caused issue with a very large bill of materials [and we all learned sql can be recursive]. Lesson: filter at as low a level as possible. Went from 100+ years to 75 milliseconds
  • Missig where clause so emailed too many people a scary message
  • Running a performance test on wifi is really slow.
  • Decompiling a jar making a change and recompiling it.
  • Running a performance test on prod. Didn’t tell security. Thought being DDoS’d
  • Deleted database. Thought was backed up vs being made permanently unavailable. Only two days of data entry to restore.
  • Exposing port publicly lets anyone delete your data
  • Ran test against prod. Looked like DOS so autoblocked headquarters. Prevented all reservations. Workaround was to use mobile site since run elsewhere.
  • Running CI on a laptop caused it to disappear when person got fired. It reappeared briefly when machine next booted up.
  • Project’s CM system is putting ode on CD and putting it in a file cabinet. Have software, but not OS or hardware to run it on
  • Added RAM instead of pagination
  • Rebooted prod (vs retired prod) by going to wrong building

They said youl could use a fake name or fake company name if you went up. Most everyone used their real name. It was funny because he kept asking if people used their real name. When I went up, I said I worked for an unnamed bank in NYC. The guy after me said he worked for an unnamed trading company in NYC.

I also liked how he “baseined” how many people would raise their hands by asking eveyone n the room t raise their hands hen he commented that 90% was like 100%

My take: I went to this session last year. It’s mostly stories from the audience which is fun and different. Great topic for lunchtime.

[2018 oracle code one] dapps/chaincode/smart contracts hands on lab

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DApps, Chaincode, Smart Contracts: Get Decentralized or we’ll go without you.
Speaker: Axel Bronder (Oracle)

For more blog posts, see The Oracle Code One table of contents

Blockchain

  • distributed database/ledger
  • consensus before write
  • immutable data (once write)
  • uses cryptography
  • distributed apps and business logic
  • smart contracts == chaincode (business apps)
  • dApps – ex: Etherium

Hyperledger Fabric

  •  open source
  • permission blockchain
  • can choose consensus model – don’t have to use mining
  • multiple channels – know channel exist, but can’t read it
  • works with different blockchain (doesn’t have to be Oracle Blockchain)
  • peers generate consensus
  • ledger – world state
  • application – ex: Postman

Lab

My take: They wanted people to pair for the lab. Which is fine. But they wanted you to pair on one computer and share the login to the cloud. My partner doesn’t speak English well so we had communication troubles. That turned out to not be my largest problem. They provided papers for two different cloud environments. For half of the participants, the environment was “slow” and timed out. After a bunch of confusion, it installed the chain but didn’t instantiate. An hour into the lab (really 40 minutes because the beginning was talking), we were told to start over. I got another timeout in the new environment and decided to leave and go to another session instead. I did read the entire lab PDF so I got the gist. (I hope our lab goes better tomorrow!)