OCL2PSQL

(Dec, 2019) OCL2PSQL-fdse19-v1 is the first version of OCL2PSQL

(Mar, 2020) OCL2PSQL-ttc2020-v2 is the second version of OCL2PSQL

(???, ????) This branch (OCL2PSQL-v3) is the third version of OCL2PSQL

The Object Constraint Language (OCL) is a textual, declarative language typically used as part of the UML standard for specifying constraints and queries on models.

OCL2PSQL implements a novel mapping from OCL to pure SQL that deals with (possibly nested) iterator expressions, without resorting to imperative features of SQL.

OCL2PSQL generates SQL queries that can be efficiently executed on mid- and large-size SQL databases.

Introduction

This web service is intended for readers of our manuscripts:

• Mapping OCL into SQL: Challenges and Opportunities Ahead. (pdf)
• OCL2PSQL: An OCL-to-SQL Code-Generator for Model-Driven Engineering. (doi.org/10.1007/978-3-030-35653-8_13)
• The TTC 2020 OCL2PSQL Case. (pdf)

Please, be aware that OCL2PSQL is an on-going research project. In particular, OCL2PSQL does NOT cover yet the full OCL language.

This table represents a detailed overview of supported Object Constraint Language (OCL) operators in our implementation OCL2PSQL. It consists of several categories, in which contains 2 columns: the operator (on the left) and the syntax example (on the right).

Class operations

||| |--------------------------|---| |allInstances | class.allInstances() | |attributes | var.att | |association ends | var.assoc |

Constants operations

||| |--------------------------|---| |Boolean Literal | {TRUE, FALSE}| |Integer Literal | {..., -2, 1, 0, 1, 2, ...}| |String Literal | 'string'|

Boolean operations

||| |--------------------------|---| |not | NOT bool-expr | |and, or| bool-expr logic-operator bool-expr'| | =, <>, >, <, ≥, ≤ | bool-expr compare-operator bool-expr'|

Iterative operations

||| |--------------------------|---| |collect | source-expr -> collect(var | body-expr) | |forAll | source-expr -> forAll(var | bool-expr) | |exists | source-expr -> exists(var | bool-expr) | |select | source-expr -> select(var | bool-expr) | |reject | source-expr -> reject(var | bool-expr) | |size | source-expr -> size()| |isEmpty | source-expr -> isEmpty()| |notEmpty | source-expr -> notEmpty()| |isUnique | source-expr -> isUnique()| |flatten¹ | source-expr -> flatten()|

¹ For the time being, this can operate ONLY after the collect operation

Quick Guideline

Interested readers can clone our project (and related submodules) using these commands:

git clone https://github.com/ocl-vgu/OCL2PSQL.git
git submodule update --init --recursive

An easy way to use OCL2PSQL library is

OCL2PSQL_2 ocl2psql = new OCL2PSQL_2();
String filePath = "/absolute/path/of/contextual/data/model";
ocl2psql.setDataModelFromFile(filePath);
ocl2psql.setDescriptionMode(true);

String oclExpression = "Car.allInstances()->collect(c.owners->isUnique())";
String finalStatement = ocl2psql.mapToString(oclExpression);

The contextual data model definition can be found in the manuscripts above.

Description mode add OCL sub-expressions as comments to generated SQL statements, it is false by default.

We provide one sample scenario where the contextual model of the OCL expressions can be translated by the model CarOwnership (See here) and the generated SQL expressions are solely intended for the database schema CarDB (See here). Also, the generated database schema can also be generated using dm2schema.