mirror of
https://github.com/adambard/learnxinyminutes-docs.git
synced 2024-12-23 17:41:41 +00:00
Revert "Fix build error in 'build/docs/cypher/index.html'"
This reverts commit b57cca8587
as the
issue has already been fixed upstream.
This commit is contained in:
parent
926a2bdc88
commit
f95558ff92
@ -16,29 +16,19 @@ Nodes
|
||||
|
||||
**Represents a record in a graph.**
|
||||
|
||||
```
|
||||
()
|
||||
```
|
||||
```()```
|
||||
It's an empty *node*, to indicate that there is a *node*, but it's not relevant for the query.
|
||||
|
||||
```
|
||||
(n)
|
||||
```
|
||||
```(n)```
|
||||
It's a *node* referred by the variable **n**, reusable in the query. It begins with lowercase and uses camelCase.
|
||||
|
||||
```
|
||||
(p:Person)
|
||||
```
|
||||
```(p:Person)```
|
||||
You can add a *label* to your node, here **Person**. It's like a type / a class / a category. It begins with uppercase and uses camelCase.
|
||||
|
||||
```
|
||||
(p:Person:Manager)
|
||||
```
|
||||
```(p:Person:Manager)```
|
||||
A node can have many *labels*.
|
||||
|
||||
```
|
||||
(p:Person {name : 'Théo Gauchoux', age : 22})
|
||||
```
|
||||
```(p:Person {name : 'Théo Gauchoux', age : 22})```
|
||||
A node can have some *properties*, here **name** and **age**. It begins with lowercase and uses camelCase.
|
||||
|
||||
The types allowed in properties :
|
||||
@ -50,9 +40,7 @@ The types allowed in properties :
|
||||
|
||||
*Warning : there isn't datetime property in Cypher ! You can use String with a specific pattern or a Numeric from a specific date.*
|
||||
|
||||
```
|
||||
p.name
|
||||
```
|
||||
```p.name```
|
||||
You can access to a property with the dot style.
|
||||
|
||||
|
||||
@ -61,24 +49,16 @@ Relationships (or Edges)
|
||||
|
||||
**Connects two nodes**
|
||||
|
||||
```
|
||||
[:KNOWS]
|
||||
```
|
||||
```[:KNOWS]```
|
||||
It's a *relationship* with the *label* **KNOWS**. It's a *label* as the node's label. It begins with uppercase and use UPPER_SNAKE_CASE.
|
||||
|
||||
```
|
||||
[k:KNOWS]
|
||||
```
|
||||
```[k:KNOWS]```
|
||||
The same *relationship*, referred by the variable **k**, reusable in the query, but it's not necessary.
|
||||
|
||||
```
|
||||
[k:KNOWS {since:2017}]
|
||||
```
|
||||
```[k:KNOWS {since:2017}]```
|
||||
The same *relationship*, with *properties* (like *node*), here **since**.
|
||||
|
||||
```
|
||||
[k:KNOWS*..4]
|
||||
```
|
||||
```[k:KNOWS*..4]```
|
||||
It's a structural information to use in a *path* (seen later). Here, **\*..4** says "Match the pattern, with the relationship **k** which be repeated between 1 and 4 times.
|
||||
|
||||
|
||||
@ -87,24 +67,16 @@ Paths
|
||||
|
||||
**The way to mix nodes and relationships.**
|
||||
|
||||
```
|
||||
(a:Person)-[:KNOWS]-(b:Person)
|
||||
```
|
||||
```(a:Person)-[:KNOWS]-(b:Person)```
|
||||
A path describing that **a** and **b** know each other.
|
||||
|
||||
```
|
||||
(a:Person)-[:MANAGES]->(b:Person)
|
||||
```
|
||||
```(a:Person)-[:MANAGES]->(b:Person)```
|
||||
A path can be directed. This path describes that **a** is the manager of **b**.
|
||||
|
||||
```
|
||||
(a:Person)-[:KNOWS]-(b:Person)-[:KNOWS]-(c:Person)
|
||||
```
|
||||
```(a:Person)-[:KNOWS]-(b:Person)-[:KNOWS]-(c:Person)```
|
||||
You can chain multiple relationships. This path describes the friend of a friend.
|
||||
|
||||
```
|
||||
(a:Person)-[:MANAGES]->(b:Person)-[:MANAGES]->(c:Person)
|
||||
```
|
||||
```(a:Person)-[:MANAGES]->(b:Person)-[:MANAGES]->(c:Person)```
|
||||
A chain can also be directed. This path describes that **a** is the boss of **b** and the big boss of **c**.
|
||||
|
||||
Patterns often used (from Neo4j doc) :
|
||||
@ -258,19 +230,13 @@ DELETE n, r
|
||||
Other useful clauses
|
||||
---
|
||||
|
||||
```
|
||||
PROFILE
|
||||
```
|
||||
```PROFILE```
|
||||
Before a query, show the execution plan of it.
|
||||
|
||||
```
|
||||
COUNT(e)
|
||||
```
|
||||
```COUNT(e)```
|
||||
Count entities (nodes or relationships) matching **e**.
|
||||
|
||||
```
|
||||
LIMIT x
|
||||
```
|
||||
```LIMIT x```
|
||||
Limit the result to the x first results.
|
||||
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user