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gopqgen

This project aims to generate common CRUD operations for a given PostgreSQL database and expose them as a gRPC API.

Why?

Are you tired of writing CRUD?
Do you realize there is actually nothing such as One-To-Many in RMDBS and all you do is deceive yourselves with Hibernate and others?
You realize SQL is already simple enough
You use PostgreSQL
You realize you can define functions inside DB instead of the your application code
How many times you debugged an ORM?
Do you want another micro-service to your next-gen-kubernetes-based application?

Note: It is a work on progress.

## Installation

go get -u github.com/mustafaakin/gopqgen

TODO Listgit

Example

For given this schema, it generates an almost valid gRPC right now.

SQL:

CREATE TABLE student (
  id SERIAL PRIMARY KEY,
  name TEXT,
  email TEXT,
  password BYTEA,
  age INT
);

CREATE TABLE teacher (
  id  SERIAL PRIMARY KEY,
  name TEXT
);

CREATE TYPE severity AS ENUM ('Easy', 'Medium', 'Hard');

CREATE TABLE course(
  id        SERIAL PRIMARY KEY,
  title     TEXT,
  teacherId INT REFERENCES teacher(id),
  severity  severity
);

CREATE TABLE membership (
  courseId INT REFERENCES course(id),
  studentId INT REFERENCES student(id)
);

-- Not that you need something like it, but just imagine
CREATE FUNCTION add(integer, integer) RETURNS integer AS
  'select $1 + $2;' LANGUAGE SQL
IMMUTABLE RETURNS NULL ON NULL INPUT;

CREATE FUNCTION IsUserInCourse(_studentId integer, _courseid integer) RETURNS boolean AS
  'select exists(select 1 from membership where studentId = _studentid AND courseid = _courseid)' LANGUAGE SQL;

CREATE FUNCTION GetStudentsOfCourse(_courseId integer) RETURNS TABLE(name text, email text) AS
  'SELECT s.name, s.email FROM
    course c,
    student s,
    membership m
  WHERE
    c.id = m.courseid AND
    s.id = m.studentid AND
    c.id = _courseId'
LANGUAGE SQL;

gRPC Proto:

syntax = "proto3";

// Enums
enum severity {
    UNKNOWN = 0;
    Easy = 1;
    Medium = 2;
    Hard = 3;
}

// Messages, Field Types
message teacher {
    int32 id = 1;
    string name = 2;
}

message AddArg {
    int32 var1 = 1;
    int32 var2 = 2;
}

message GetstudentsofcourseOut {
    string name = 1;
    string email = 2;
}

message IsuserincourseArg {
    int32 _studentid = 1;
    int32 _courseid = 2;
}

message course {
    int32 id = 1;
    string title = 2;
    int32 teacherid = 3;
    severity severity = 4;
}

message membership {
    int32 courseid = 1;
    int32 studentid = 2;
}

message student {
    int32 id = 1;
    string name = 2;
    string email = 3;
    bytes password = 4;
    int32 age = 5;
}

// Service Definition
service DatabaseService {
    // SELECT id, title, teacherid, severity FROM course
    rpc ListCourse(VoidRequest) returns (stream course) {}
    // SELECT * FROM getstudentsofcourse($1)
    rpc Getstudentsofcourse(int32) returns (GetstudentsofcourseOut) {}
    // SELECT id, title, teacherid, severity FROM course WHERE `id` = $1
    rpc GetCourseById(int32) returns (course) {}
    // SELECT id, name, email, password, age FROM student WHERE `id` = $1
    rpc GetStudentById(int32) returns (student) {}
    // SELECT id, name FROM teacher WHERE `id` = $1
    rpc GetTeacherById(int32) returns (teacher) {}
    // SELECT * FROM add($1, $2)
    rpc Add(AddArg) returns (int32) {}
    // SELECT * FROM isuserincourse($1, $2)
    rpc Isuserincourse(IsuserincourseArg) returns (bool) {}
    // SELECT courseid, studentid FROM membership
    rpc ListMembership(VoidRequest) returns (stream membership) {}
    // SELECT id, name, email, password, age FROM student
    rpc ListStudent(VoidRequest) returns (stream student) {}
    // SELECT id, name FROM teacher
    rpc ListTeacher(VoidRequest) returns (stream teacher) {}
}