Data and Query Basics
A comparative introduction to organizing and querying data in relational and graph databases.

Organizing data

Relational and graph databases organize data is distinctly different ways.

Relational databases

Traditional relational databases divide data into tables, columns, and rows.

Graph databases

Similar to other graph databases, TerminusDB organizes data in objects. Objects have properties, properties link to other objects. A network of interlinked objects forms a graph structure - the foundation of graph databases.
Using objects rather than cells enables the creation of databases that closely model the real world.

Example using a family tree

A family tree database stores data representing individuals, their parents, and grandparents.

Relational databases

The table below represents a model for storing this scenario in a relational database.

Graph databases

The diagram further below illustrates the equivalent graph database model. An advantage of the graph model is that it represents real-world objects more accurately, making the model intuitive and easier to understand.

Table: Family tree in a relational database

person_id
name
DOB
mother_id
father_id
1
Bob
01/10/1979
2
3
2
Zoe
04/02/1956
4
5
3
Bob Snr
28/11/1952
6
7
4
Ada
17/04/1922
NULL
NULL
5
Tom
01/09/1909
NULL
NULL
6
Eva
17/04/1923
NULL
NULL
7
Ray
03/10/1913
NULL
NULL

Diagram: Family tree in a graph database

Querying data

Relational database queries

Many relational databases use the Structured Query Language (SQL.) The example below uses a two-query approach to get the name of mother, then grandmother. Note the second query uses two nested sub-queries.

Graph database queries

TerminusDB's purpose-built Web Object Query Language (WOQL) is an easier-to-use alternative to SQL. The example below demonstrates the same query using WOQL. WOQL uses triple patterns to get both names in one short query. There are no joins - joins are implied by using the same ID in different parts of the query. Using v:mother_id multiple times creates the chain:
v:person_id = mother => v:mother = mother => v:grandmother

Code: Family tree traversal using SQL

select name
from table_name
where person_id = (
select mother_id
from table_name
where name = "Bob")
select name
from table_name
where person_id = (
select mother_id
from table_name
where person_id = (
select mother_id
from table_name
where name = "Bob"))

Code: Family tree traversal using WOQL

WOQL.and
(
WOQL.triple("v:person", "mother", "v:mother_id"),
WOQL.triple("v:mother_id", "name", "v:mother_name"),
WOQL.triple("v:mother_id", "mother", "v:grandmother_id"),
WOQL.triple("v:grandmother_id", "name", "v:grandmother_name"),
)
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On this page
Organizing data
Relational databases
Graph databases
Example using a family tree
Relational databases
Graph databases
Querying data
Relational database queries
Graph database queries