Graph databases
An overview
Natalia Oskina
Zuhlke Engineering Ltd
Graph Databases
An overview
Natalia Oskina
Zuhlke Engineering
Title Text
Agenda
- CAP?
- What kind of a creature is Graph DB?
- Graph DB vs relational DB
- Is it a silver bullet? Downsides
- Neo4J
- Cypher vs SQL
- Can we use it? Real Use cases
- Demo
CAP theorem
- Consistency - all nodes see the same data at the same time
Brewer's theorem
- Availability - every request receives a response about whether it succeeded or failed
- Partition tolerance - the system continues to operate despite arbitrary partitioning due to network failures
What is a graph?
G = (V, E)
Graph database
- If you would need to represent a system with all data of every movie ever made, how would you model it?
- You need to cover movie names, actors, directors, budget, dates, costs, location, ratings, shows, tickets...
What about Bacon number?
Graph database
"No broken links"
- Nodes
- Relationships
- Properties
Graph DB vs Relational DB
Graph DB vs Relational DB
Graph DB vs Relational DB
- Chaotic data model. Irregualar, complex structure
- Highly complex relationships between entities
- Relationships are very different
- Check only relationships of the node, not the whole database
Examples
- Neo4J (Java, .Net, Python, JavaScript)
- AllegroGraph (C#, C, Java, Lisp, Python)
- Oracle Spatial and Graph ( Java, PI/SQL)
- AngoDB(C, C++, JavaScript)
Neo4J
- JVM Based
- Billions of entities
- Support ACID
- Using Cypher
Cypher
Functions like: WHERE, ORDER BY, SKIP LIMIT, AND, p.unitPrice > 10
Select and Return Records
SQL
SELECT p.*
FROM products as p;
Cypher
MATCH (p:Product)
RETURN p;
Field Access, Ordering and Paging
SQL
SELECT p.ProductName, p.UnitPrice
FROM products as p
ORDER BY p.UnitPrice DESC
LIMIT 10;
Cypher
MATCH (p:Product)
RETURN p.productName, p.unitPrice
ORDER BY p.unitPrice DESC
LIMIT 10
Downsides
- Use a lot of storage
- Relational DB is much faster when operating a huge number of records
- Licence is expensive
Panama Papers
https://offshoreleaks.icij.org/
Panama Papers
- 950 000 nodes
- 1,2 millions edges (4GB)
Facebook social graph
Demo
Questions?