Merge pull request #39 from AlexicaWright/add-indexes-data-importer

Add indexes data importer

Author: AlexicaWright

documentation/data-importer.adoc

@@ -99,8 +99,7 @@ Workspace guesses each datatype based on a sample of the values it found.
 Always double-check this when working with unfamiliar data.
 For example, Northwind's date/time columns are identified as strings, but you can edit that if you want to.
 ====
-// TODO: properties with same name... this needs rewording for clarity.
-
+// TODO: properties with same name... this needs rewording for clarity
 
 == Relationships and IDs
 
@@ -120,7 +119,6 @@ You can also specify properites and their data types in isolation from mapping b
 You can then map a column from your data file to the property in the file mapping tab.
 ====
 
-
 === Create the Product node
 
 Now you just need to repeat the process you followed for `Order` and create a `Product` node from the `products.csv` file.
@@ -138,6 +136,34 @@ If you're unsure if you've followed the steps correctly so far, you can go ahead
 button::Load Northwind node mapping[role=NX_IMPORT_LOAD,endpoint={northwind-subset-node-only-mapping-zip-file}]
 ====
 
+== Constraints and indexes
+
+To ensure accuracy of your data and support read performance, Data Importer automatically creates a uniqueness constraint and a corresponding index on the property you select as the node ID.
+You can add further indexes in addition to the mandatory constraint and index.
+
+Constraints and indexes have their own tab in the highlight:import/import-mapping-panel[mapping details panel].
+Use the `+`-sign to add an index and then select which property to add the index on.
+
+Data Importer generates a name for the index and the index type created is Neo4j's default index.
+If you make a mistake, select the erroneous index and click the trash-can to delete it.
+
+If you know that you are going to use a property regularly, it is good practice to add an index to it.
+For example, if you doing administrative work with Northwind, you may be interested in the order dates.
+See if you can add an index to the `orderDate` property that will help you with that!
+
+[%collapsible]
+.Hint
+====
+From the highlight:import/import-mapping-panel[mapping details panel], tap the `+` and select the `orderDate` property.
+====
+
+[NOTE]
+====
+Only the properties you mapped from the _Definition_ tab are available to create indexes on.
+To modify the selection, you need to go back to the _Definition_ tab.
+====
+
+To learn more about indexes and constraints, see link:https://neo4j.com/docs/cypher-manual/current/indexes/[Cypher Manual -> Indexes] and link:https://neo4j.com/docs/cypher-manual/current/constraints/[Cypher Manual -> Constraints] repsectively.
 
 == Create relationships