Upload
others
View
7
Download
0
Embed Size (px)
Citation preview
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
CSCC01 FALL 2021WEEK 3 - NOSQL GRAPH DBS. SOFTWARE ARCHITECTURE.
PLANNING AND PRIORITIZING.
Ilir Dema
University of Toronto
Sep 22-24, 2021
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
WHAT IS NOSQL?
INTRO TO NOSQL• The growth of Web raised the need for larger, more
scalable storage solutions.• a variety of key-value storage solutions were designed for
better availability, simple querying, and horizontal scaling.• This new kind of data store became more and more robust,
offering many of the features of the relational databases.• Different storage design patterns emerged, including
key-value storage, column storage, object storage, and themost popular one, document storage.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
RELATIONAL VS DOCUMENT-ORIENTED DB
• In a common relational database, data is stored in differenttables, often connected using a primary to foreign keyrelation.
• A program will later reconstruct the model using variousSQL statements to arrange the data in some kind ofhierarchical object representation.
• Document-oriented databases handle data differently.• Instead of using tables, they store hierarchical documents
in standard formats, such as JSON and XML.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
RELATIONAL DB EXAMPLE
blog post model - data stored in different tables:
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
DOCUMENT-ORIENTED DB EXAMPLE
• In a document-based database, the blog post will be storedcompletely as a single document that can later be queried.
• For instance, in a database that stores documents in aJSON format, the blog post document would probably looklike the following code snippet:
This model will allow faster read operations since yourapplication won’t have to rebuild the objects with every read.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
WHAT IS NEO4J?
A GRAPH DATABASE
• Uses graphs to store and process the data• Data is organized into nodes and relationships• Properties are stored in either nodes or relationships• Recently, Neo4j and Google Cloud have teamed up to
deliver Neo4j for Google Cloud, the Neo4j graph databasedelivered as a Google Cloud Platform (GCP) nativeservice.
• Neo4j’s native data manipulation language is Cypher.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
GRAPHS
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
HOW ABOUT DATA?
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
HOW ABOUT DATA?
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
COMPARE TO SQL
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
TRANSITION TO GRPAHS
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
MODELING WITH GRAPHS
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
NEO4J IS FULLY ACID COMPLIANT ...
ACID• ATOMIC: The whole transaction or nothing• CONSISTENT: Upon completion of a transaction, the db is
structurally sound• ISOLATION: Transactions appear to apply in isolation from
one another• DURABLE: Once a transaction is complete, it persists,
even in case of various failures
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
WELCOME TO CYPHER
NOT JUST A QUERY LANGUAGE
• Declarative, readable, expressive• Made for CRUD on graphs• Based on patterns• Interacts safely with the remote database using a binary
protocol called Bolt
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
PROPERTY GRAPHS
A PROPERTY GRAPH HAS
• Nodes (:PERSON)• have properties ({name: ”Donald”})
• Relationships [:WORKS_WITH]• also have properties ({company: ”Bluecat”})
AN EXAMPLE OF CREATECREATE
(: PERSON {name:"Donald"})-[:WORKS_WITH {company: "Bluecat"}]->
(: PERSON {name: "Jasvir"})
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
CYPHER WORKS BASED ON PATTERNS
WHO WORKS WITH JASVIR AT BLUECAT?MATCH(p1: PERSON)
-[:WORKS_WITH {company:"Bluecat"}]->(:PERSON {name:"Jasvir"})
RETURNp1
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
SOFTWARE DESIGN
TONY HOARE:There are two ways of constructing a software design: One wayis to make it so simple that there are obviously no deficiencies,and the other way is to make it so complicated that there are noobvious deficiencies.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
LEVELS OF DESIGN
• Architectural design (also: high-level design)• architecture - the overall structure: main modules and their
connections• design that covers the main use-cases of the system• addresses the main non-functional requirements (e.g.,
throughput, reliability)• hard to change
• Detailed design (also: low-level design)• the inner structure of the main modules• may take the target programming language into account• detailed enough to be implemented in the programming
language
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
SOFTWARE ARCHITECTURE
DEFINITION
A software architecture is a description of the subsystems andcomponents of a software system and the relationshipsbetween them. Subsystems and components are typicallyspecified in different views to show the relevant functional andnonfunctional properties of a software system. The softwarearchitecture of a system is an artifact. It is the result of thesoftware development activity.
Buschmann et al., Pattern-Oriented Software Architecture, ASystem of Patterns
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
THE MVC PATTERN
• Model:• Contains Data Objects• Encapsulates the application state• Responds to state queries/updates• Exposes application functionality
• View:• Renders the model (i.e. the screen representation of the
data).• Note: The user is not necessarily a human. For example,
programs want to view the data using some text format (e.g.XML, or JSON)
• Sends user input to the Controller• Controller:
• Defines application behavior• Maps user actions to Model updates• Controls the flow of the application.• Defines the way the user interface reacts to the user input.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
THE MVC AS ARCHITECTURAL PATTERN
MVC INTEGRATES A FEW DESIGN PATTERNS
• Model uses Observer to keep views and controllersupdated on the latest state changes
• View and Controller implement Strategy pattern. Controlleris the behavior of the View and can be easily exchangedwith another controller if you want different behaviour.
• View uses Composite pattern to manage the componentsof the display.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
THE 3-TIERED ARCHITECTURE
WHAT DOES THREE TIERED MEAN?• The presentation tier is the front end layer in the 3-tier
system and consists of the user interface.• The application tier contains the functional business logic
which drives an application’s core capabilities.• The data tier comprises of the database/data storage
system and data access layer.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
THE 3-TIERED ARCHITECTURE
WHERE DOES IT DIFFER FROM MVC?• MVC and 3-tier architecture are topologically different.• Conceptually the three-tier architecture is linear. MVC
architecture is triangular: the view sends updates to thecontroller, the controller updates the model, and the viewgets updated directly from the model.
• A fundamental rule in a three tier architecture is the clienttier never communicates directly with the data tier.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
MICROSERVICES ARCHITECTURE
WHAT DOES MICROSERVICES MEAN?• Develop a single application as a suite of small services• Each running separately and communicating via HTTP.• These services are independently and automatically
deployable.• They may use different programming languages and use
different data storage technologies.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
RELEASE PLANNING
• During the release planning meeting the following thingsare established:
• Major release goals• Release plan• Potential sprint goals• Completion date
• As each sprint progresses the burndown of story pointsmeasure the velocity of work, which can be used todetermine progress and adapt the plan as we go
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
SPRINT PLANNING
• The team decides (reviews) velocity - how many storypoints will they do in this sprint.
• Most priority stories from the product backlog are selected,filling up the velocity.
• team never overcommits!• The tasks from each selected story is broken down to build
the sprint backlog• Meeting may include additional domain experts (not part of
the team) to help answer any questions and aid in timeestimations.
• Implementation details are discussed• Product owner must be present to answer any questions
related to the design
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
TASK PLANNING
• Tasks are estimated in hours• Estimation is an ideal time (without interruptions / problems)
• After all tasks have been estimated the hours are totaledup and compared against the remaining hours in the sprintbacklog
• If there is room, the team picks more stuff from productbacklog and updates the velocity.
• All planning decisions are recorded on the tracker.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
TRACKING PROGRESS
• Information about progress, impediments and sprintbacklog of tasks needs to be readily available
• How close a team is to achieving their goals is alsoimportant
• Scrum employs a number of practices for tracking thisinformation:
• Task cards• Burndown charts• Task boards• War rooms
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
BURNDOWN CHART
Source: Wikipedia
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
TASKBOARD
Source:https://manifesto.co.uk/agile-concepts-scrum-task-board/
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
DAILY SCRUM MEETINGS
• 15 minute meeting that everyone must attend• No sitting down, team stands in a circle and answers the
following questions: What have I done since the lastmeeting?
• What am I going to accomplish between now and the nextmeeting?
• What are the problems or impediments that are slowing medown?
• It is NOT for solving problems - the Scrum Master mustensure that all side conversations are kept to a minimum
• Solving problems happens throughout the rest of the day• Can be evolved to meet a specific team’s requirements, but
the purpose must remain the same (status, commitment,improvement)
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
SPRINT REVIEWS
• Occur on the last day of the sprint• Team and stakeholders come together to play the game
and discuss the work accomplished• Product owner accepts or declines the results of the sprint• If a feature is declined, the owner will decide if it is returned
to the backlog or simply dropped• Honesty is crucial• Cannot discourage criticism simply because a lot of work
was put in
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
HOW TO PRIORITIZE?
• Prior to each sprint, the product owner is allowed tochange the priorities in the product backlog
• Decisions can be based on the following criteria:• Value: what value does the story add to the player buying
the game, helps maximize ROI• Cost: some features may prove too costly to implement and
affect ROI• Risk: uncertainty about value/cost• Knowledge: if the product owner doesn’t have enough
information about feature to do a proper estimate they canintroduce a spike to explore it and get more info
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
KANO MODEL
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
KANO MODEL
• Developed by Noriaka Kano in the 1970s and 1980s whilestudying quality control and customer satisfaction.
• Basic features that a user expects to be there and work willnever score highly on satisfaction, but can take inordinateamounts of effort to build and maintain.
• At the opposite end of the spectrum are features thatdelight the user. These score very highly on satisfactionand in many cases may not take as much investment.Small incremental improvements here have an outsizedimpact on customer satisfaction.
• Satisfiers: requirements that customers are not expecting,but the more of them that are included, the happier thecustomer.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
PRIORITIZING DESIRABILITY
SELECTING FEATURES
• If you have a choice of two things and cant decide, takeboth.
- Gregory Corso• When you come to a fork in the road, take it.- Yogi Berra
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
ASSESSING THEMES ON THE KANO MODEL
• Kano proposed determining the category of a feature byasking two questions:
• how the user would feel if the feature were present in theproduct and
• how the user would feel if it were absent.• The answers to these questions are on the same five-point
scale:1 I like it that way2 I expect it to be that way3 I am neutral4 I can live with it that way5 I dislike it that way
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
EXAMPLE
THE SWIMSTATS WEBSITE
• SwimStats is a hypothetical website for swimmers andswim coaches.
• SwimStats will be sold as a service to competitiveage-group, school, and college swim teams.
• Coaches will use it to keep track of their roster ofswimmers, organize workouts, and prepare for meets
• Swimmers will use the site to see meet results, check theirpersonal records, and track improvements over time.
• Officials at swim meets will enter results into the system.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
THE SWIMSTATS WEBSITE
Source: Cohn, Agile Estimating and Planning.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
KANO MODEL FOR SWIMSTATS
• Suppose we are contemplating three new features:• The ability to see a graph of a swimmer’s times in an event
over the past season• The ability for swimmers to post autobiographical profiles• The ability for any registered site member to upload photos
• To determine which type of feature this is, we would surveyprospective users asking them:
• If you can graph a swimmer’s times in an event over thepast season, how do you feel?
• If you cannot graph a swimmer’s times in an event over thepast season, how do you feel?
• If swimmers can post autobiographical profiles, how do youfeel?
• If swimmers cannot post autobiographical profiles, how doyou feel?
• If you can upload photos, how do you feel?• If you cannot upload photos, how do you feel?
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
SAMPLE ANSWERS
Source: Cohn, Agile Estimating and Planning.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
MANAGING CONFLICTING ANSWERS
Source: Cohn, Agile Estimating and Planning.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
DISTRIBUTION OF RESULTS FROM SURVEYING USERS.
Source: Cohn, Agile Estimating and Planning.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
VALUE/COST: A PROXY FOR ROI
• A working definition for ROI is Value/Cost.• Need to have a relative measure of value and cost, w.r.t
other features.• Why?
• Easy to understand and calculate• It makes apparent economical sense
• We have a proxy for effort - story points.• What is a proxy for value?
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
WHAT ELSE DO WE NEED TO ACCOUNT FOR?
• First, we need to quantify value, and numbers can be readfrom the Kano graph.
• Next, need to consider the cost of delay. How much relativevalue do we lose if we deliver x-feature after y-feature?
• Last, but not least, need to consider how much do wereduce risk and uncertainty.
• If two user stories have same ROI, the one with highestCoD must be prioritized first.
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
COST OF DELAY
DEFINE COST OF DELAY
• What is cost of delay?• The impact of time on value (or rephrased: Impact of time
on the outcomes we hope to achieve)• It combines urgency and value.
• Cost of delay = value x urgency• Urgency: Describes the development of value over a given
timeframe
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
URGENCY: SHORT BENEFIT HORIZON.
Source: http://www.ontheagilepath.net/
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
URGENCY: LONG LIFE BUT SMALLER PEAK DUE TO
LATE ENTRY.
Source: http://www.ontheagilepath.net/
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
URGENCY: LONG LIFE , WITH PEAK NOT AFFECTED BY
DELAY.
Source: http://www.ontheagilepath.net/
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
COMPUTING COST OF DELAY.
Source: http://www.ontheagilepath.net/
NoSQL Neo4j Software Architecture Planning Prioritizing the Product Backlog
EXAMPLE
Feature Effort Value ROI CoD Priority1 1 3 3 3 12 3 6 2 4 23 10 20 2 3 3