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https://github.com/oracle/pgql-lang
PGQL is an SQL-based query language for property graphs
https://github.com/oracle/pgql-lang
graph-database graph-queries graphql oracle pgql query-language
Last synced: 1 day ago
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PGQL is an SQL-based query language for property graphs
- Host: GitHub
- URL: https://github.com/oracle/pgql-lang
- Owner: oracle
- License: other
- Created: 2016-06-21T19:45:40.000Z (over 8 years ago)
- Default Branch: main
- Last Pushed: 2024-05-28T23:21:37.000Z (7 months ago)
- Last Synced: 2024-05-29T08:25:41.904Z (7 months ago)
- Topics: graph-database, graph-queries, graphql, oracle, pgql, query-language
- Language: Java
- Homepage: https://pgql-lang.org/
- Size: 13.4 MB
- Stars: 173
- Watchers: 18
- Forks: 44
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE.txt
- Security: SECURITY.md
Awesome Lists containing this project
README
# PGQL - Property Graph Query Language
PGQL is an SQL-based query language for the [property graph data model](https://pgql-lang.org/spec/latest/#property-graph-data-model), bringing graph pattern matching capabilities to SQL and NoSQL users.
See the website for a language specification and any newsworthy updates:
[](https://pgql-lang.org/)
## PGQL Parser and Static Query Validator
This Git repository contains a parser for PGQL with the following features:
- Easy-to-understand IR: Given a query string, the parser returns an easy-to-understand intermediate representation (IR) of the query as a set of Java objects
- see [__GraphQuery.java__](graph-query-ir/src/main/java/oracle/pgql/lang/ir/GraphQuery.java)
- Query validation: built-in to the parser is a static query validator that provides meaningful caret-style (e.g. `^^^`) error messages:
_Example 1_
```sql
SELECT n.name, o.name
FROM MATCH (n) -[e]-> (m)
```
```
Error(s) in line 1:
SELECT n.name, o.name
^
Unresolved variable
```
_Example 2_
```sql
SELECT AVG(n.age), n
FROM MATCH (n:Person)
```
```
Error(s) in line 1:
SELECT AVG(n.age), n
^
Aggregation expected here since SELECT has other aggregation
```
- __Pretty printing__: invoking `GraphQuery.toString()` will "pretty print" the graph query, which turns unformatted queries into formatted ones:
```sql
SELECT n.name FROM MATCH
(n:Person) WHERE n.name = 'Anthony'
OR n.name = 'James'
```
```sql
SELECT n.name
FROM MATCH (n:person)
WHERE n.name = 'Anthony'
OR n.name = 'James'
```
- __Code completion__: given a (partial) query string and a cursor position, the parser can suggest a set of code completions, including built-in functions, labels and properties. These completions can for example be used by an interactive web editor.
By providing the parser with metadata about the graph (existing properties and labels), the completions will also include label and property suggestions.
## Build and Install the Parser
PGQL's parser can be built on Linux, macOS or Window.
First install JDK 1.8 or higher and Maven 3.5.4 or higher.
Then, follow these instructions:
On Linux or macOS:
- Build and install to your local Maven repository by running `sh install.sh`
On Windows:
- Open System Properties and add a new variable `JAVA_OPTS` with value `-Xms512m -Xmx1024m -Xss16m`
- Build and install to your local Maven repository by running `install_on_windows.bat`
## Getting Started
After you have installed the parser like explained above, parse two [example](example/src/main/java/oracle/pgql/lang/example/Main.java) queries:
- On Linux or macOS execute `cd example; sh run.sh`
- On Windows execute:
```
cd example
mvn clean package exec:java -Dexec.mainClass="oracle.pgql.lang.example.Main" -Dexec.cleanupDaemonThreads=false
```
```java
public class Main {
public static void main(String[] args) throws PgqlException {
try (Pgql pgql = new Pgql()) {
// parse query and print graph query
PgqlResult result1 = pgql.parse("SELECT n FROM MATCH (n:Person) -[e:likes]-> (m:Person) WHERE n.name = 'Dave'");
System.out.println(result1.getPgqlStatement());
// parse query with errors and print error messages
PgqlResult result2 = pgql.parse("SELECT x, y, FROM MATCH (n) -[e]-> (m)");
System.out.println(result2.getErrorMessages());
}
}
}
```
The AST returned by the parser is a [GraphQuery](graph-query-ir/src/main/java/oracle/pgql/lang/ir/GraphQuery.java) object. This would be the input to your query planner.
## Documentation
See the [PGQL Specification](https://pgql-lang.org/spec/latest/).
## Development
- Download Eclipse with Spoofax 2.5.18 pre-installed [here](https://spoofax.dev/release/note/2.5.18/)
- Import the following projects into Eclipse (`File>Import...>Maven>Existing Maven Projects>Browse...`):
- `graph-query-ir`: Java representation of graph queries
- `pqgl-spoofax`: Spoofax implementation of PGQL (parser + error checks)
- `pgql-lang`: translation of Spoofax AST into `graph-query-ir`
## Contributing
This project welcomes contributions from the community. Before submitting a pull request, please [review our contribution guide](./CONTRIBUTING.md)
## Security
Please consult the [security guide](./SECURITY.md) for our responsible security vulnerability disclosure process
## License
Copyright (c) 2023 Oracle and/or its affiliates.
Released under the Apache and the Universal Permissive License (UPL) as shown at
.