CodeMash Day One

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Codemash 2019

CodeMash Day One

CodeMash (http://www.codemash.org/) is a technical conference targeted towards developers which is held in the first of January in Sandusky, Ohio at the Kalahari Resort and Conference Center.  In 2019, it was held during January 8-11 with the first two days as a precompiler (workshops), and the last two days are the conference.  See http://www.codemash.org/schedule/.  It is widely attended by developers from around the country.  The conference has vendors who demonstrate their development products, like JetBrains and Quicken, as well as technical recruiters.

I attended the conference this year and here is a quick summary.

Two workshops from Day One are described below:

Graph Databases

Neo4J
Day one had a workshop on graph databases by Greg Jordan.  https://twitter.com/gmjordan, https://www.linkedin.com/in/gmjordan, https://www.graphstory.com/
 
According to the presenter, graph databases are:
  • A type of No-SQL database that supports connections, graphs.
  • More change resilient than traditional databases.
  • Performance is better than relational as database size increases.  Relational slows down around 100 million rows.
  • Easily handles complexity as compared to complex joins in relational databases.
Graph database work well in the following contexts:
  • Social – twitter
  • Interest – user interests
  • Consumption – user consumption of products
  • Intent – users, consumptions, interests
Graphs are best for complex associations.  Not good for data that is not related.  Getting better at aggregation of data but relational databases are better at aggregations.  Relational databases have a common SQL.  NeoJ has Open Cypher as a common query language.
 
MATCH (c:CONTENT)-[R:HAS]->(T:TAG:NAME {username: “greg”}))
 
MATCH (u:User)
return u
 
Labels are like tags.  Properties are like fields.  You can remove a property for one specific record.
 
Batch import tool
  • Import millions of records
  • Rebuilds the entire graph – new graph
LOAD CSV, loads thousands of records.
 
 
Install directory:
/Users/alanbeal/CodeMash2019/GraphDatabases/up-and-running-with-graph-databases-software-MacOS/neo4j/
 
If windows, stop neo4j and delete the old graph.db, then cd into bin
.\neo4j-admin import –nodes csvs/nodes/Category.csv –nodes csvs/nodes/Product.csv –nodes csvs/nodes/Review.csv –nodes csvs/nodes/User.csv –relationships csvs/rels/CC.csv –relationships csvs/rels/PC.csv –relationships csvs/rels/PP.csv –relationships csvs/rels/PR.csv –relationships csvs/rels/RC.csv –ignore-missing-nodes=true
***************
IF Mac
Stop Neo4j. bin/neo4j stop
Delete the graph.db file under database
./import-builder-neo4j.sh “/Users/gregjordan/dev/neo4j/code-mash-precompiler/neo4j-enterprise-3.4.9/bin/csvs”
Start Neo4j, bin/neo4j start’
 
***************
// run these one at a time
CREATE INDEX ON :Category(categoryId)
CREATE INDEX ON :Category(categoryName)
CREATE INDEX ON :Location(locationId)
CREATE INDEX ON :Location(zip)
CREATE INDEX ON :Purchase(purchaseId)
CREATE INDEX ON :Product(productId)
CREATE INDEX ON :Status(statusId)
CREATE INDEX ON :User(userId)
CREATE INDEX ON :User(username)
:schema
***************
then….
***************
// run these one at a time
return row
LIMIT 5
***************
CREATE (:Location { locationId: row.locationId,business:row.business, city: row.city, county: row.county, usState: row.usState, zip: row.zip, latitude: toFloat(row.lat), longitude: toFloat(row.lon)})
***************
LOAD CSV WITH HEADERS FROM ‘file:///Users.csv‘ AS row
CREATE (u:User { userId:row.userId, username:row.username,firstname:row.firstname,lastname:row.lastname })
***************
LOAD CSV WITH HEADERS FROM ‘file:///Purchase.csv‘ AS row
CREATE (p:Purchase { purchaseId:row.purchaseId })
***************
LOAD CSV WITH HEADERS FROM ‘file:///Purchase.csv‘ AS row
MATCH (u:User { userId: row.userId } ),(p:Purchase { purchaseId: row.purchaseId  } )
MERGE (u)-[:MADE_PURCHASE]->(p)
***************
LOAD CSV WITH HEADERS FROM ‘file:///Purchase.csv‘ AS row
MATCH (p:Purchase { purchaseId: row.purchaseId  } ), (product:Product { productId: row.productId } )
MERGE (p)-[:PURCHASE_CONTAINS]->(product)
***************
MATCH p=(u:User {userId: “1”})-[:MADE_PURCHASE]->(pro)-[r:PURCHASE_CONTAINS]->() RETURN p LIMIT 2
***************
/// OH NO! forgot to add the timestamp field for when the purchase occured
LOAD CSV WITH HEADERS FROM ‘file:///Purchase.csv‘ AS row
MATCH (p:Purchase { purchaseId: row.purchaseId  } )
SET p.timestamp=toInt(row.purchaseDateAsLong)
***************
LOAD CSV WITH HEADERS FROM ‘file:///CurrentStatus.csv‘ AS row
CREATE (s:Status { statusId:row.statusId, userIdStatusId:row.userIdStatusId, statusText:row.statusText, timestamp:toInt(row.timestamp) })
***************
LOAD CSV WITH HEADERS FROM ‘file:///nextstatus1.csv‘ AS row
CREATE (s:Status { statusId:row.statusId, userIdStatusId:row.userIdStatusId, statusText:row.statusText, timestamp:toInt(row.timestamp) })
***************
LOAD CSV WITH HEADERS FROM ‘file:///nextstatus2.csv‘ AS row
CREATE (s:Status { statusId:row.statusId, userIdStatusId:row.userIdStatusId, statusText:row.statusText, timestamp:toInt(row.timestamp) })
***************
LOAD CSV WITH HEADERS FROM ‘file:///CurrentStatus.csv‘ AS row
MATCH (u:User { userId: row.userId  } ), (s:Status { statusId:row.statusId} )
MERGE (u)-[:CURRENT_STATUS]->(s)
***************
LOAD CSV WITH HEADERS FROM ‘file:///nextstatus1.csv‘ AS row
MATCH (s:Status { statusId:row.lastStatusId} ), (ns:Status { statusId:row.statusId} )
MERGE (s)-[:NEXT_STATUS]->(ns)
***************
LOAD CSV WITH HEADERS FROM ‘file:///nextstatus2.csv‘ AS row
MATCH (s:Status { statusId:row.nextToLastStatusId} ), (ns:Status { statusId:row.statusId} )
MERGE (s)-[:NEXT_STATUS]->(ns)
***************
USING PERIODIC COMMIT 10000
LOAD CSV WITH HEADERS FROM ‘file:///follows.csv‘ AS row
MATCH (user:User { userId: row.userId  } ), (userToFollow:User { userId: row.followingid  } )
MERGE (user)-[:FOLLOWS]->(userToFollow)
***************
MATCH (u:User {userId: “1” })
WITH u
MATCH (u)-[:FOLLOWS*0..1]->(f)
RETURN f
***************
MATCH (u:User {userId: “1” })
WITH u
MATCH (u)-[:FOLLOWS*0..1]->(f)
WITH DISTINCT f,u
MATCH (f)-[:CURRENT_STATUS]->(ls)-[:NEXT_STATUS*0..3]->(s)
RETURN s.statusId as statusId, s.statusText as statusText, s.timestamp as timestamp, f.username as username, f=u as owner
ORDER BY s.timestamp DESC
***************
// run the match to location->products
match (u:Location),(p:Product)
with u,p
limit 5000000
where rand() < 0.1
create (u)-[:LOCATION_HAS_PRODUCT]->(p);
***************
MATCH (l:Location)
WHERE (l)-[:LOCATION_HAS_PRODUCT]->()
RETURN l.zip
***************
// add a point layer
CALL spatial.addPointLayer(‘geom’)
***************
// index the locations
MATCH (l:Location) WITH collect(l) as locedafterdark
CALL spatial.addNodes(‘geom’, locedafterdark)
YIELD count
RETURN count
***************
///checked that it works
CALL spatial.withinDistance(“geom”,{latitude:35.1531,longitude:-90.0555},5.0)
YIELD node as location
RETURN location
***************

ReactNative

React Native

Second half of day one was a workshop on ReactNative by Tommy Graves from Root Insurance.  ReactNative is from Facebook and Root Insurance has one of the largest ReactNative mobile applications with other 100 screens.

Uses javascript and native views and components. Can jump into native code.  ReactNative is one language, supporting many platforms.  ReactNative has all the advantages of React with low ramp up time for new developers.

When not to use ReactNative:
  • Already have mobile developers
  • Mainly using the native aspects of the device
Some difficulties with ReactNative:
  • Testing
  • Navigation
  • Performance
  • Upgrading
  • Debugging – if errors in native code, then difficult to debug
Props are component parameters allowing data to be passed around.

ReactNative – from Facebook
 
Clone the repository at https://github.com/TAGraves/production-ready-rn-codemash-2019 and run `npm install`.
 
 Do the exercises:
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