Data types, Schema and Type System
It’s time to talk about data types and nodes
Starting in version 1.1, Dgraph has support for a type system. At the moment, the type system is basic but can be used already to categorize nodes and query them based on their type. The type system is also used during expand queries.
So in order to Expand or Delete nodes. You need to define your Types correctly. You can see in detail more about the Type System here.
Data types and Schema
There was some magic in the last query because some of the queried
edges returned a value (
age), but some were edges to
other nodes (
owns_pet) that themselves had further properties.
The truth is that there is a schema to tell us how to interpret an edge.
The visualization won’t be much use this time. Have a look at the JSON to find out about the schema of the example.
There are two kinds of nodes in a graph, let’s call them nodes and
values (or literals). In the example, nodes representing people have
name edge to a
string value and an
age edge to an
int value. A value can’t have any edges coming out of it.
Here are the types you can use to store values in Dgraph.
||signed 64 bit integer|
||double precision floating point number|
||identifiers stored as strings|
||RFC3339 time format with optional timezone eg: 2006-01-02T15:04:05.999999999+10:00 or 2006-01-02T15:04:05.999999999|
||geometries stored using go-geom|
There’s also the
uid type, for nodes. The schema tells us the
friend edge goes from one node to another, but not to a value.
There’s lots more about schema later in the tutorial. For now, though, we know more about the structure of our graph and the types of things in it.