What is Cypher Query Language in Neo4j?

• Neo4j has its own query language called Cypher. Cypher uses a similar syntax to SQL (Structured Query Language).
• Cypher is designed to be a humane query language, suitable for both developers and (importantly, we think) operations professionals.

• Here's an example of a Cypher statement:

• This Cypher statement returns a "Person" node where the name property is "Homer Flinstone".
• If this was SQL querying a relational database, it might look more like this:

• However, remember, Neo4j doesn't store its data in tables like the relational database model. It's all in nodes and relationships.
• So the Cypher query above is querying nodes, their labels, and their properties. The SQL example on the other hand, is querying tables, rows, and columns.
• Query time is reported in the tabular view, don’t rely on that exact timing though it includes the latency and (de-)serialization costs, not just the actual query execution time.
• SQL was designed to be used with relational database management systems (DBMS). Neo4j is a NoSQL DBMS, in that it doesn't use the relational model and it doesn't use SQL.
• Cypher was designed specifically for working with the Neo4j data model, which is all about nodes and their relationships with each other.

• Cypher uses ASCII-Art to represent schemas. This is a usual thing to remember when first learning the language. If you forget how to write something, just visualize how the graph will look and it should help.

• The main things to remember:
• Nodes are represented by parentheses, which look like circles. Like this: (node)
• Relationships are represented by arrows. Like this: ->
• Information about a relationship can be inserted between square brackets. Like this: [:KNOWS]

• Here are some more points to remember when working with Cypher:
• Nodes usually have labels. Examples could include "Person", "User", "Actor", "Employee", "Customer".
• Nodes usually have properties. Properties provide extra information about the node. Examples could include "Name", "Age", "Born", etc
• Relationships can also have properties.
• Relationships usually have a type (this is basically like a node's label). Examples could include "KNOWS", "LIKES", "WORKS_FOR", "PURCHASED", etc.

• So looking at the above example again:

• We can see that:
• The node is surrounded by parentheses ().
• Person is the node's label.
• name is a property of the node.