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[cypher/en] Fix syntax for code blocks (#2706)
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Théo Gauchoux
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@ -11,34 +11,37 @@ This tutorial assumes that you already know graph concepts like nodes and relati
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[Read more here.](https://neo4j.com/developer/cypher-query-language/)
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`// There is just single-line comments in Cypher`
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Nodes
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---
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**Represents a record in a graph.**
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**`()`** It's an empty *node*, to indicate that there is a *node*, but it's not relevant for the query.
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```()```
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It's an empty *node*, to indicate that there is a *node*, but it's not relevant for the query.
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**`(n)`** It's a *node* refered by the variable **n**, reusable in the query. It begins with lowercase and uses camelCase.
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```(n)```
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It's a *node* refered by the variable **n**, reusable in the query. It begins with lowercase and uses camelCase.
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**`(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.
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```(p:Person)```
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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.
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**`(p:Person:Manager)`** A node can have many *labels*.
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```(p:Person:Manager)```
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A node can have many *labels*.
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**`(p:Person {name : 'Théo Gauchoux', age : 22})`** A node can have some *properties*, here **name** and **age**. It begins with lowercase and uses camelCase.
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```(p:Person {name : 'Théo Gauchoux', age : 22})```
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A node can have some *properties*, here **name** and **age**. It begins with lowercase and uses camelCase.
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The types allowed in properties :
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* Numeric
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* Boolean
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* String
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* List of previous primitive types
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**Warning : there isn't datetime property in Cypher ! You can use String with a specific pattern or a Numeric from a specific date.**
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- Numeric
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- Boolean
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- String
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- List of previous primitive types
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**`p.name`** You can access to a property with the dot style.
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*Warning : there isn't datetime property in Cypher ! You can use String with a specific pattern or a Numeric from a specific date.*
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```p.name```
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You can access to a property with the dot style.
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Relationships (or Edges)
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@ -46,13 +49,17 @@ Relationships (or Edges)
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**Connects two nodes**
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**`[: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.
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```[:KNOWS]```
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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.
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**`[k:KNOWS]`** The same *relationship*, refered by the variable **k**, reusable in the query, but it's not necessary.
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```[k:KNOWS]```
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The same *relationship*, refered by the variable **k**, reusable in the query, but it's not necessary.
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**`[k:KNOWS {since:2017}]`** The same *relationship*, with *properties* (like *node*), here **since**.
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```[k:KNOWS {since:2017}]```
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The same *relationship*, with *properties* (like *node*), here **since**.
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**`[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.
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```[k:KNOWS*..4]```
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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.
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Paths
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@ -60,13 +67,17 @@ Paths
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**The way to mix nodes and relationships.**
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**`(a:Person)-[:KNOWS]-[b:Person]`** A path describing that **a** and **b** know each other.
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```(a:Person)-[:KNOWS]-[b:Person]```
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A path describing that **a** and **b** know each other.
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**`(a:Person)-[:MANAGES]->[b:Person]`** A path can be directed. This path describes that **a** is the manager of **b**.
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```(a:Person)-[:MANAGES]->[b:Person]```
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A path can be directed. This path describes that **a** is the manager of **b**.
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**`(a:Person)-[:KNOWS]-[b:Person]-[:KNOWS]-[c:Person]`** You can chain multiple relationships. This path describes the friend of a friend.
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```(a:Person)-[:KNOWS]-[b:Person]-[:KNOWS]-[c:Person]```
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You can chain multiple relationships. This path describes the friend of a friend.
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**`(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**.
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```(a:Person)-[:MANAGES]->[b:Person]-[:MANAGES]->[c:Person]```
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A chain can also be directed. This path describes that **a** is the boss of **b** and the big boss of **c**.
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Patterns often used (from Neo4j doc) :
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@ -85,6 +96,7 @@ path = shortestPath( (user)-[:KNOWS*..5]-(other) )
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```
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Create queries
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---
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@ -148,6 +160,7 @@ WHERE a.name = "Jacquie" AND b.name = "Michel"
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CREATE (a)-[:KNOWS]-(b)
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```
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Update queries
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---
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@ -179,6 +192,7 @@ WHERE p.name = "Théo Gauchoux"
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SET p:Internship
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```
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Delete queries
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---
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@ -212,17 +226,24 @@ DELETE n, r
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```
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*Seriously, it's the `rm -rf /` of Cypher !*
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Other useful clauses
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---
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**`PROFILE`** Before a query, show the execution plan of it.
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**`COUNT(e)`** Count entities (nodes or relationships) matching **e**.
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**`LIMIT x`** Limit the result to the x first results.
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```PROFILE```
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Before a query, show the execution plan of it.
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```COUNT(e)```
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Count entities (nodes or relationships) matching **e**.
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```LIMIT x```
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Limit the result to the x first results.
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Special hints
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---
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* You can execute a Cypher script stored in a **.cql** file directly in Neo4j (it's an import). However, you can't have multiple statements in this file (separed by **;**).
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* Use the Neo4j shell to write Cypher, it's really awesome.
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* The Cypher will be the standard query language for all graph databases (known as **OpenCypher**).
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- There is just single-line comments in Cypher, with double-slash : // Comments
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- You can execute a Cypher script stored in a **.cql** file directly in Neo4j (it's an import). However, you can't have multiple statements in this file (separed by **;**).
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- Use the Neo4j shell to write Cypher, it's really awesome.
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- The Cypher will be the standard query language for all graph databases (known as **OpenCypher**).
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