EdgeQL

EdgeQL is the primary language of EdgeDB. It is used to define, mutate, and query data. EdgeQL encompasses four items in general:

Querying language | SDL | DDL | Administration

Most frequently used in EdgeQL is the querying language. EdgeQL is a functional language in that every expression is a composition of one or more queries. The querying language looks like this:

SELECT Issue {
    number,
    body,
    due_date
}
FILTER
    EXISTS .due_date
ORDER BY
    .due_date
LIMIT 3;

The simplicity of EdgeQL queries might remind you of GraphQL a bit, and EdgeQL does indeed have a similar straightforwardness while being more powerful (see some [comparisons of syntax here]() for details on that).

SDL (schema definition language). SDL is used to describe migrations to a specific schema state. In SDL you write the final types and relationships without needing to worry about making declarations in any particular order. Items in a schema written in SDL look like this:

type Movie {
    required property title -> str;
    required link director -> Person;
    multi link actors -> Person;
}

type Person {
    required property name -> str;
}

DDL (data definition language). DDL is the less frequently used (but often convenient) cousin of SDL. DDL is used to transform schema step by step instead of all at once. The order is important in DDL because it involves issuing one command after another instead of describing the final form.

So you can’t create Movie first using DDL because it links to Person. The two are created in this order:

db> 
... 
... 

CREATE TYPE Person {
   CREATE REQUIRED PROPERTY name -> str;
};

CREATE: OK

db> 
... 
... 
... 
... 

CREATE TYPE Movie {
    CREATE REQUIRED PROPERTY title -> str;
    CREATE REQUIRED LINK director -> Person;
    CREATE MULTI LINK actors -> Person;
};

CREATE: OK

SDL is sort of like a 3D printer: you set the final shape and it puts it together for you. DDL is like building a house with traditional methods: to add a window you first need a frame, to have a frame you need a wall, and so on. But DDL is great for making quick changes to your schema without a new migration, in the same way that you can replace a window without describing the whole house to do it. In practice, most people stick to SDL until they get comfortable and only then begin to experiment with DDL.

The remainder: this includes infrequently used but critical items involved in database administration. Start with the Administration link below to see how to configure a database, set roles, passwords, and so on using EdgeDB.