16.1.4.4 Two Tables (TWO_TABLES)

When configured to use file as datastore, the Two Tables format becomes a text file format similar to the Edge List format, with the only difference that the vertices and edges are stored in two different files. The vertices file contains vertex IDs followed by vertex properties. The edges file contains the source vertices and target vertices, followed by edge properties.

A graph with V vertices, having N vertex properties and M edge properties would be represented in two files as shown in the following:

vertices.ttt:

<V-1>  <V-1, NP-1> ... <V-1, NP-N>
<V-2>  <V-2, NP-1> ... <V-2, NP-N>
...
<V-V> <V-V, NP-1> ... <V-V, NP-N>

edges.ttt:

<V-1> <V-1, VG-1> <EP-1> ... <EP-M>
<V-1> <V-1, VG-2> <EP-1> ... <EP-M>
...
<V-V> <V-V, VG-1> <EP-1> ... <EP-M>

Example 16-5 Graph in Two Tables Text format

The following example shows the graph of 4 vertices (1, 2, 3 and 4), each having a double and a string property, and 3 edges, each having a boolean and a date property, encoded in Two Tables Text format:

vertices.ttt:

1 8.0 "foo"
2 4.3 "bar"
3 6.1 "bax"
4 17.78 "f00"

edges.ttt:

2 1 false "1985-10-18 10:00:00"
3 2 true "1961-12-30 14:45:14"
3 4 false "2001-01-15 07:00:43"

Note:

If you are planning on storing big graphs you must consider Two Tables Text format in order to save disk space.