Document parameters

Reviewers: teon.banek, buda

Reviewed By: teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D575

docs/user_technical/open-cypher.md

@@ -422,6 +422,39 @@ functions.
  `endsWith`   | Check if the first argument ends with the second.
  `contains`   | Check if the first argument has an element which is equal to the second argument.
 
+#### Parameters
+
+When automating the queries for Memgraph, it comes in handy to change only
+some parts of the query. Usually, these parts are values which are used for
+filtering results or similar, while the rest of the query remains the same.
+
+Parameters allow reusing the same query, but with different parameter values.
+The syntax uses the `$` symbol to designate a parameter name. We don't allow
+old Cypher parameter syntax using curly brace. For example, you can parameterize
+filtering a node property:
+
+    MATCH (node1 {property: $propertyValue}) RETURN node1
+
+You can use parameters instead of any literal in the query, but not instead of
+property maps even though that is allowed in standard openCypher. Following
+example is illegal in Memgraph:
+
+    MATCH (node1 $propertyValue) RETURN node1
+
+To use parameters with Python driver use following syntax:
+
+    session.run('CREATE (alice:Person {name: $name, age: $ageValue}',
+                name='Alice', ageValue=22)).consume()
+
+To use parameters which names are integers you will need to wrap parameters in
+a dictionary and convert them to strings before running a query:
+
+    session.run('CREATE (alice:Person {name: $0, age: $1}',
+                {'0': "Alice", '1': 22})).consume()
+
+To use parameters with some other driver please consult appropriate
+documentation.
+
 ### Differences
 
 Although we try to implement openCypher query language as closely to the

docs/user_technical/upcoming-features.md

@@ -69,21 +69,6 @@ paths of length between 2 and 4 can be obtained with a query like:
 
     MATCH (node1) -[*2..4]-> (node2)
 
-#### Parameters
-
-When automating the queries for Memgraph, it comes in handy to change only
-some parts of the query. Usually, these parts are values which are used for
-filtering results or similar, while the rest of the query remains the same.
-
-Parameters will allow using the same query, but with different parameter
-values. The syntax uses the `$` symbol to designate a parameter name. For
-example, parameterizing filtering a node property:
-
-    MATCH (node1 {property: $propertyValue}) RETURN node1
-
-Other than helping users reuse similar queries, parameters should improve the
-performance of running those queries.
-
 #### Functions
 
 Memgraph's openCypher implementation supports the most useful functions, but