Storing graph data in a relational database
Embodiments include methods, systems and computer program products for storing graph data for a directed graph in a relational database. Aspects include creating a plurality of relational tables for the graph data, using a processor on a computer, the plurality of relational tables including adjacency tables and attribute tables. Each row of the attribute tables is dedicated to a subject of the graph data in the dataset and stores a JavaScript Object Notation (JSON) object corresponding to the subject. Each row of the adjacency tables includes a hashtable containing properties and values of the subject for that row.
1. A method of storing graph data for a directed graph in a relational database, the method comprising:
creating a plurality of relational tables for the graph data, wherein the graph data comprises a plurality of vertexes and a plurality of edges, using a processor on a computer, the plurality of relational tables including adjacency tables and attribute tables wherein:
each row of the attribute tables is dedicated to a subject of the graph data in the dataset and stores a JavaScript Object Notation (JSON) object corresponding to the subject; and
each row of the adjacency tables comprises a hashtable comprising properties and values of the subject for that row, wherein the hashtable further comprises an index value corresponding to a value shared by a plurality of edges originating from at least one vertex in the plurality of vertexes, wherein the index value further corresponds to a secondary adjacency table comprising edge data for edges originating from the at least one vertex in the plurality of vertexes;
wherein the adjacency tables include:
an incoming adjacency table, wherein each row of the incoming adjacency table is dedicated to one of the plurality of vertexes of the graph data and stores data regarding edges that terminate at that vertex; and
an outgoing adjacency table, wherein each row of the outgoing adjacency table is dedicated to one of the plurality of the vertexes of the graph data and stores data regarding edges that originate at that vertex;
receiving a query for traversing the graph data stored in the relational database;
parsing the query into a set of ordered operations;
translating each of the set of ordered operations into a fragment using a template selected based on an operation type, wherein the template comprises at least one of a common table expression fragment and a stored procedure;
assembling the fragments into a single query; and
transmitting the single query to the relational database for processing.
2. The method of claim 1 , wherein the attribute table includes a vertex attribute table, wherein each row of the vertex attribute table is dedicated to one of a plurality of vertexes of the graph data and stores a JavaScript Object Notation (JSON) object corresponding to that vertex.
3. The method of claim 1 , wherein the attribute table includes an edge attribute table, wherein each row of the edge attribute table is dedicated to one of the plurality of edges of the directed graph and stores a JavaScript Object Notation (JSON) object corresponding to that edge.