Overview

pgschemapc is a prototype implementation of PGSchema with support for property constraints.

Installation and Building

You can download a binary from the download page, where you will also find the compiled packages for the installation on your system using a package manager.

Building

The project has been implemented in Rust and uses cargo for building. Once you install cargo, you can run:

cargo build

to compile and generate a binary which will be available in target/debug/pgschemapc. If you want a more performant binary, you can use the --release option.

Getting started

In order to verify that the installation has been successful, you can run the following command to check that everything is working as expected.

pgschemapc --version

Once you have pgschemapc installed and verified, the next step is to start using the different subcommands that are bundled within the tool. You can run:

pgschemapc --help
A simple prototype tool to process and validate PG-Schemas with property constraints

Usage: pgschemapc [COMMAND]

Commands:
  pgs       Process and validate property graph schemas
  pg        Process and validate property graphs
  map       Process and validate type map associations
  validate  Validate a property graph with a property graph schema and some associated type map
  help      Print this message or the help of the given subcommand(s)

Options:
  -h, --help
          Print help (see a summary with '-h')

  -V, --version
          Print version

pg - Property Graphs

Property graphs contain a list of node or edge declarations separated by ;.

An example can be:

(n1: Person { name: "Alice", age: 23 });
(n2: Person & Student { name: "Bob" });
(n3: Course { name: "Algebra" });
[e1: (n1) -[ :knows { since: 2020 }]->(n2)];
[e2: (n2)-[:knows { start: 2024, end: 2025 }]->(n3)]

Notice that node declarations are declared between parenthesis ( and ) while edge declarations are declared between square brackets [ and ].

The full grammar is available here.

pgs - Property Graph Schemas

A property graph schema contains a list of CREATE node/edge/graph TYPE statements. It follows the grammar from the PGSchema paper with some extensions for property constraints.

The full grammar is available here.

An example property graph schema is:

CREATE NODE TYPE ( PersonType : Person {
    name: STRING,
    OPTIONAL age: INTEGER
}) ;
CREATE NODE TYPE ( StudentType : Person & Student {
    name: STRING,
    OPTIONAL age: INTEGER
}) ;
CREATE NODE TYPE ( CourseType: Course {
    name: STRING
})

map - Type map associations

Type map associations are used to trigger validation. They associate nodes/edges in the property graph with type names in the property graph schema.

The full grammar of type maps is available here

An example type map association is:

n1:PersonType,
n2:StudentType,
n3:CourseType

Notice that type maps can also be used to specify the expected result of validation which can be positive or negative. For negative validation results, we use a ! after the colon. These result type maps are employed in the test-suite which is available here.

validate property graphs

The validate command can be used to validate nodes or edges from a Property Graph to check if they conform with type node declarations in a Property Graph Schema. To trigger validation it is necessary to add a third parameter, which is a type map association file which declares which nodes/edges should be checked against which type names.

An example validation can be run by:

pgschemapc validate --graph examples/course.pg --schema examples/course.pgs --map examples/course.map

test-suite

The project contains a list of tests in the folder tests.

The test cases are defined with four files:

• A property graph, usually with the extension .pg
• A property graph schema, usually with the extension .pgs
• An input type map association file: .map which declares which nodes/edges in the property graph should validate with which type names in the property graph schema.
• A result type map association file, which declares the expected result.