Graph Database Management Systems provide an effective and efficient solution to data storage in current scenarios where data are more and more connected, graph models are widely used, and systems need to scale to large data sets. In this framework, the conversion of the persistent layer of an application from a relational to a graph data store can be convenient but it is usually an hard task for database administrators. In this paper we propose a methodology to convert a relational to a graph database by exploiting the schema and the constraints of the source. The approach supports the translation of conjunctive SQL queries over the source into graph traversal operations over the target. We provide experimental results that show the feasibility of our solution and the efficiency of query answering over the target database.

1. Roberto De
Virgilio
affiliated
Antonio
Maccioni
aff
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d
Riccardo
Torlone
topic
topic
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author
author
or
auth
Converting Relational to Graph Databases
In
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pr
GRADES 2013
23 June 2013
when
where
New York, USA
affiliated workshop
where

2. Relational Database Migration
SQL
select *
from T
where T.A1 = v1
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

3. R2G: Features
●
Data migration
●
Query translation
●
●
Automatic non-naïve
approach
Try to minimize the
memory accesses
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

4. Graph Modeling of Relational DB
●
Full Schema Paths:
FR.fuser → US.uid → US.uname
FR.fuser → FR.fblog → BG.bid → BG.bname
FR.fuser → FR.fblog → BG.bid → BG.admin → US.uid → US.uname
...
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

5. Basic Concepts
•
Joinable tuples t1 ∈ R1 and t2 ∈ R2:
●
•
there is a foreign key constraint between R1.A and R2.B
and t1[A] = t2[B].
Unifiability of data values t1[A] and t2[B]:
●
●
●
(i) t1=t2 and both A and B do not belong to a multiattribute key;
(ii) t1 and t2 are joinable and A belongs to a multiattribute key;
(iii) t1 and t2 are joinable, A and B do not belong to a
multi-attribute key and there is no other tuple t 3 that is
joinable with t2.
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

6. Data Migration (1)
●
Identify unifiable data exploiting schema
and constraints
FR.fuser
US.uid
US.uname
n1
FR.fuser : u01
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

7. Data Migration (2)
●
Identify unifiable data exploiting schema
and constraints
FR.fuser
US.uid
US.uname
n1
FR.fuser : u01
US.uid : u01
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

8. Data Migration (3)
●
Identify unifiable data exploiting schema
and constraints
FR.fuser
US.uid
US.uname
n1
FR.fuser : u01
US.uid : u01
US.uname : Date
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

9. Data Migration (4)
●
Identify unifiable data exploiting schema
and constraints
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

10. Query Translation
Gremlin
GRADES 2013
Converting Relational to Graph Databases
XQuery
New York, 23-06-2013

11. Experimental Results
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

12. Conclusion
•
Automatic data mapping
•
Conjunctive query translation into a
path traversal query
•
Independent of a specific GDBMS
•
Efficient exploitation of Graph Database
Features
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

13. Future Work
•
Consider frequent queries to migrate
data
•
Consider wider range of queries than CQ
•
Improve compactness of the graph
database
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013

14. Thanks For The Attention
... demo presentation during the
following interactive session!
GRADES 2013
Converting Relational to Graph Databases
New York, 23-06-2013