Creating schema in the Gremlin console

Creating a graph database schema using Groovy in the Gremlin console.

Creating a data model for a graph database is the critical first step towards creating a schema. Once the data model is designed and a graph is created, defining the schema for the vertices and edges and their properties is the next step in creating a graph database. Gremlin-Groovy is packaged with the Apache TinkerPop Gremlin console. Use either Gremlin-Groovy to create a script that contains the Gremlin commands, or enter the commands directly into the Gremlin console.

Procedure

Start the Gremlin console.
Create a new graph to store the data and alias a graph traversal to run queries. If you are reusing a graph that you previously created, drop the graph schema and data.
Optional: On the remote Gremlin Server, set the timeout value to max to prevent client-side timeouts. Use this setting to ensure that script processing will complete.
```
gremlin> :remote config timeout max
```
Optional: If running large scripts, set the evaluation_timeout value to max to prevent server-side timeouts. Use this setting to ensure that script processing will complete.
```
graph.schema().config().option("graph.traversal_sources.g.evaluation_timeout").set("PT10M")
```
A script that creates schema is shown in the Example at the bottom of this page. The script file is loaded and run on the remote Gremlin Server. This script will not work if you have previously run scripts from the Quick Start unless the schema and any data has been cleared from the graph.
```
gremlin> :load /tmp/RecipeSchema.groovy
```
The following steps show the details of the full script broken down into sections.
Define the properties for the vertices and the edges. The data type of the property is specified in addition to a key name. All properties created in this example are Text, Integers, or Timestamps. Other data types are available. Properties will be used to retrieve selective subsets of the graph and to retrieve stored values. Properties are global in nature, and the pairing of a vertex label and a property will uniquely identify a property for use in traversals. Edge properties are expensive to update, as they are deleted and recreated, so use edge properties in situations that warrant their use.
```
// Property Keys 
// Check for previous creation of property key with ifNotExists() 
schema.propertyKey('name').Text().ifNotExists().create()        
schema.propertyKey('gender').Text().create()
schema.propertyKey('instructions').Text().create()
schema.propertyKey('category').Text().create()
schema.propertyKey('year').Int().create()
schema.propertyKey('timestamp').Timestamp().create()
schema.propertyKey('ISBN').Text().create()
schema.propertyKey('calories').Int().create()
schema.propertyKey('amount').Text().create()
schema.propertyKey('stars').Int().create()
// single() is optional, as it is the default
schema.propertyKey('comment').Text().single().create()
// Example of a multiple property that can have several values
// Next 4 lines define two properties, then create a meta-property 'livedIn' on 'country'  
// A meta-property is a property of a property
// EX: 'livedIn': '1999-2005' 'country': 'Belgium'     
// schema.propertyKey('nickname').Text().multiple().create()    
// schema.propertyKey('country').Text().create()                        
// schema.propertyKey('livedIn').Text().create()                        
// schema.propertyKey('country').Text().properties('livedIn').create()
```
Property keys can be checked for prior existence with ifNotExists(). Property keys can be created with either single or multiple cardinality with single() or multiple(). The default is single cardinality which does not have to be specified, but it can be explicitly stated as in the example.

Meta-properties, or properties of properties, can be created using propertyKey() followed by properties(). The property key must exist prior to the creation of a meta-property.
Define the vertex labels. The vertex labels identify the type of vertices that can be created.
```
/// Vertex Labels
schema.vertexLabel('author').ifNotExists().create()
schema.vertexLabel('recipe').create()
// Example of creating vertex label with properties
// schema.vertexLabel('recipe').properties('name','instructions').create()
schema.vertexLabel('ingredient').create()
schema.vertexLabel('book').create()
schema.vertexLabel('meal').create()
schema.vertexLabel('reviewer').create()
// Example of custom vertex id:
// schema.propertyKey('city_id').Int().create()
// schema.propertyKey('sensor_id').Uuid().create()
// schema().vertexLabel('FridgeSensor').partitionKey('city_id').clusteringKey('sensor_id').create()
```
Vertex labels can be checked for prior existence using ifNotExists(). Vertex labels can be created along with properties. Vertex labels can be created with custom vertex ids, rather than the standard vertex ids.
Note: Standard auto-generated ids are deprecated with DSE 6.0. Custom ids will undergo changes, and specifying vertex ids with partitionKey and clusteringKey will likely become the normal method.

DSE Graph limits the number of vertex labels to 200 per graph.
Define the edge labels. The edge labels identify the type of edges that can be created.
```
// Edge Labels
schema.edgeLabel('authored').ifNotExists().create()
schema.edgeLabel('created').create()
schema.edgeLabel('includes').create()
schema.edgeLabel('includedIn').create()
schema.edgeLabel('rated').properties('stars').connection('reviewer','recipe').create()
```
Edge labels can be checked for prior existence using ifNotExists(). Edge labels can be created with adjacent vertex labels identified using connection().

Define indexes that can speed up the query processing. All types of indexes are presented here.

// Vertex Indexes
// Secondary
schema.vertexLabel('author').index('byName').secondary().by('name').add()
// Materialized	  		
schema.vertexLabel('recipe').index('byRecipe').materialized().by('name').add()
schema.vertexLabel('meal').index('byMeal').materialized().by('name').add()
schema.vertexLabel('ingredient').index('byIngredient').materialized().by('name').add()
schema.vertexLabel('reviewer').index('byReviewer').materialized().by('name').add()
// Search
// schema.vertexLabel('recipe').index('search').search().by('instructions').asText().add()
// schema.vertexLabel('recipe').index('search').search().by('instructions').asString().add()
// If more than one property key is search indexed
// schema.vertexLabel('recipe').index('search').search().by('instructions').asText().by('category').asString().add()

// Edge Index
schema.vertexLabel('reviewer').index('ratedByStars').outE('rated').by('stars').add()

// Example of property index using meta-property 'livedIn': 
// schema().vertexLabel('author').index('byLocation').property('country').by('livedIn').add()

After creating the graph schema, examine the schema to verify. This command is included as the last command of the full script.

 schema.describe()

==>schema.propertyKey("member_id").Smallint().single().create()
schema.propertyKey("instructions").Text().single().create()
schema.propertyKey("amount").Text().single().create()
schema.propertyKey("gender").Text().single().create()
schema.propertyKey("year").Int().single().create()
schema.propertyKey("calories").Int().single().create()
schema.propertyKey("stars").Int().single().create()
schema.propertyKey("community_id").Int().single().create()
schema.propertyKey("ISBN").Text().single().create()
schema.propertyKey("name").Text().single().create()
schema.propertyKey("comment").Text().single().create()
schema.propertyKey("category").Text().single().create()
schema.propertyKey("timestamp").Timestamp().single().create()
schema.edgeLabel("authored").multiple().create()
schema.edgeLabel("rated").multiple().properties("stars").create()
schema.edgeLabel("includedIn").multiple().create()
schema.edgeLabel("created").multiple().create()
schema.edgeLabel("includes").multiple().create()
schema.vertexLabel("meal").properties("name").create()
schema.vertexLabel("meal").index("byMeal").materialized().by("name").add()
schema.vertexLabel("ingredient").properties("name").create()
schema.vertexLabel("ingredient").index("byIngredient").materialized().by("name").add()
schema.vertexLabel("author").properties("name").create()
schema.vertexLabel("author").index("byName").secondary().by("name").add()
schema.vertexLabel("book").create()
schema.vertexLabel("recipe").properties("name").create()
schema.vertexLabel("recipe").index("byRecipe").materialized().by("name").add()
schema.vertexLabel("reviewer").properties("name").create()
schema.vertexLabel("reviewer").index("byReviewer").materialized().by("name").add()
schema.vertexLabel("reviewer").index("ratedByStars").outE("rated").by("stars").add()

schema.edgeLabel("rated").connection("recipe", "reviewer").connection("reviewer", "recipe").add()

Example

// RECIPE SCHEMA

// To run in Studio, copy and paste all lines to a cell and run.

// To run in Gremlin console, use the load command
// :load /tmp/RecipeSchema.groovy

    	
// Property Keys 
// Check for previous creation of property key with ifNotExists() 
schema.propertyKey('name').Text().ifNotExists().create()        
schema.propertyKey('gender').Text().create()
schema.propertyKey('instructions').Text().create()
schema.propertyKey('category').Text().create()
schema.propertyKey('year').Int().create()
schema.propertyKey('timestamp').Timestamp().create()
schema.propertyKey('ISBN').Text().create()
schema.propertyKey('calories').Int().create()
schema.propertyKey('amount').Text().create()
schema.propertyKey('stars').Int().create()
// single() is optional, as it is the default
schema.propertyKey('comment').Text().single().create()
// Example of a multiple property that can have several values
// Next 4 lines define two properties, then create a meta-property 'livedIn' on 'country'  
// A meta-property is a property of a property
// EX: 'livedIn': '1999-2005' 'country': 'Belgium'     
// schema.propertyKey('nickname').Text().multiple().create()    
// schema.propertyKey('country').Text().create()                        
// schema.propertyKey('livedIn').Text().create()                        
// schema.propertyKey('country').Text().properties('livedIn').create()  
    		
// Vertex Labels
schema.vertexLabel('author').ifNotExists().create()
schema.vertexLabel('recipe').create()
// Example of creating vertex label with properties
// schema.vertexLabel('recipe').properties('name','instructions').create()
schema.vertexLabel('ingredient').create()
schema.vertexLabel('book').create()
schema.vertexLabel('meal').create()
schema.vertexLabel('reviewer').create()
// Example of custom vertex id:
// schema.propertyKey('city_id').Int().create()
// schema.propertyKey('sensor_id').Uuid().create()
// schema().vertexLabel('FridgeSensor').partitionKey('city_id').clusteringKey('sensor_id').create()
                
// Edge Labels
schema.edgeLabel('authored').ifNotExists().create()
schema.edgeLabel('created').create()
schema.edgeLabel('includes').create()
schema.edgeLabel('includedIn').create()
schema.edgeLabel('rated').properties('stars').connection('reviewer','recipe').create()
                
// Vertex Indexes
// Secondary
schema.vertexLabel('author').index('byName').secondary().by('name').add()
// Materialized	  		
schema.vertexLabel('recipe').index('byRecipe').materialized().by('name').add()
schema.vertexLabel('meal').index('byMeal').materialized().by('name').add()
schema.vertexLabel('ingredient').index('byIngredient').materialized().by('name').add()
schema.vertexLabel('reviewer').index('byReviewer').materialized().by('name').add()
// Search
// schema.vertexLabel('recipe').index('search').search().by('instructions').asText().add()
// schema.vertexLabel('recipe').index('search').search().by('instructions').asString().add()
// If more than one property key is search indexed
// schema.vertexLabel('recipe').index('search').search().by('instructions').asText().by('category').asString().add()

// Edge Index
schema.vertexLabel('reviewer').index('ratedByStars').outE('rated').by('stars').add()

// Property index using meta-property 'livedIn': 
schema.vertexLabel('author').index('byLocation').property('country').by('livedIn').add()

// Schema description
// Use to check that the schema is built as desired
schema.describe()