edgedb 强大的对象关系数据库

edgedb 是一个强大的对象关系数据库，构建在pg 之上。

包含的特性：

• 严格的强类型模式;
• 强大而富有表现力的查询语言;
• 丰富的标准库;
• 内置支持模式迁移;
• 本机GraphQL支持。

数据模型

从表现上，类似graphql 的type 定义,如下：

type User {
    required property name -> str;
}

type Person {
    required property first_name -> str;
    required property last_name -> str;
}

type Review {
    required property body -> str;
    required property rating -> int64 {
        constraint min_value(0);
        constraint max_value(5);
    }

    required link author -> User;
    required link movie -> Movie;

    required property creation_time -> local_datetime;
}

type Movie {
    required property title -> str;
    required property year -> int64;
    required property description -> str;

    multi link directors -> Person;
    multi link cast -> Person;

    property avg_rating := math::mean(.<movie[IS Review].rating);
}

edgeql

类似sql,但是很强大

SELECT User {
    id,
    name,
    image,
    latest_reviews := (
        WITH UserReviews := User.<author
        SELECT UserReviews {
            id,
            body,
            rating,
            movie: {
                id,
                title,
                avg_rating,
            }
        }
        ORDER BY .creation_time DESC
        LIMIT 10
    )
}
FILTER .id = <uuid>$id

graphql 支持

需要进行开启

CONFIGURE SYSTEM INSERT Port {
    protocol := "graphql+http",
    database := "tutorial",
    address := "127.0.0.1",
    port := 8888,
    user := "http",
    concurrency := 4,
};

查询方法：

{
    Movie {
        title
        year
    }
}

参考资料

https://edgedb.com/blog/edgedb-1-0-alpha-1/
https://github.com/edgedb/edgedb