Expression Aliases

An alias is a named set of values produced by an expression.

Aliases can be referred to like regular types in other expressions. Aliases over queries that return objects essentially define a dynamic subtype of the original object type, which may have additional properties and links as may be specified by a shape in the alias expression.

Consider the following:

type User {
    required property name -> str;
    multi link friends -> User;
}

alias UserAlias := User {
    # declare a computable link
    friend_of := User.<friends[IS User]
};

One benefit that the UserAlias provides is making EdgeQL queries more legible:

SELECT
    User.<friends[IS User].name
FILTER
    .name = 'Alice';

# vs

SELECT
    UserAlias.friend_of.name
FILTER
    .name = 'Alice';

Another benefit is that this UserAlias can now be exposed via GraphQL providing access to the computable link friend_of, that would otherwise be inexpressible in GraphQL:

{
    UserAlias(
        filter: {name: {eq: "Alice"}}
    ) {
        friend_of {
            name
        }
    }
}