Primer

This page is indended as a rapid-fire overview of SDL syntax so you can hit the ground running with EdgeDB. Refer to the linked pages for more in-depth documentation.

Object types

Object types contain properties and links to other object types. They are analogous to tables in SQL.

  1. type Movie {
  2.   property title -> str;  # optional by default
  3. }

See Schema > Object types.

Optional and required properties

  1. type Movie {
  2.   required property title -> str;       # required
  3.   property release_year -> int64;       # optional
  4. }

See Schema > Properties.

Constraints

  1. type Movie {
  2.   required property title -> str {
  3.     constraint unique;
  4.     constraint min_len_value(8);
  5.     constraint regexp(r'^[A-Za-z0-9 ]+$');
  6.   }
  7. }

See Schema > Constraints.

Indexes

  1. type Movie {
  2.   required property title -> str;
  3.   required property release_year -> int64;
  5.   index on (.title);                        # simple index
  6.   index on ((.title, .release_year));       # composite index
  7.   index on (str_trim(str_lower(.title)));   # computed index
  8. }

The id property, all links, and all properties with exclusive constraints are automatically indexed.

See Schema > Indexes.

Computed properties

  1. type Movie {
  2.   required property title -> str;
  3.   property uppercase_title := str_upper(.title);
  4. }

See Schema > Computeds.

  1. type Movie {
  2.   required property title -> str;
  3.   link director -> Person;
  4. }
  6. type Person {
  7.   required property name -> str;
  8. }

Use the required and multi keywords to specify the cardinality of the relation.

  1. type Movie {
  2.   required property title -> str;
  4.   link cinematographer -> Person;             # zero or one
  5.   required link director -> Person;           # exactly one
  6.   multi link writers -> Person;               # zero or more
  7.   required multi link actors -> Person;       # one or more
  8. }
  10. type Person {
  11.   required property name -> str;
  12. }

To define a one-to-one relation, use an exclusive constraint.

  1. type Movie {
  2.   required property title -> str;
  3.   required link stats -> MovieStats {
  4.     constraint exclusive;
  5.   };
  6. }
  8. type MovieStats {
  9.   required property budget -> int64;
  10.   required property box_office -> int64;
  11. }

See Schema > Links.

Links can be computed. The example below defines a backlink.

  1. type Movie {
  2.   required property title -> str;
  3.   multi link actors -> Person;
  4. }
  6. type Person {
  7.   required property name -> str;
  8.   link acted_in := .<actors[is Movie];
  9. }

See Schema > Computeds > Backlinks.

Schema mixins

  1. abstract type Content {
  2.   required property title -> str;
  3. }
  5. type Movie extending Content {
  6.   required property release_year -> int64;
  7. }
  9. type TVShow extending Content {
  10.   required property num_seasons -> int64;
  11. }

See Schema > Object types > Inheritance.

  1. abstract type Content {
  2.   required property title -> str;
  3. }
  5. type Movie extending Content {
  6.   required property release_year -> int64;
  7. }
  9. type TVShow extending Content {
  10.   required property num_seasons -> int64;
  11. }
  13. type Franchise {
  14.   required property name -> str;
  15.   multi link entries -> Content;
  16. }

See Schema > Links > Polymorphism.