Location, Auto-increment Sequence Fields

Location

Saving a location on record

const Photo = skygear.Record.extend('photo');
const photo = new Photo({
  'subject': 'Hong Kong',
  'location': new skygear.Geolocation(22.39649, 114.1952103),
});

Querying records by distance

Get all photos taken within 400 meters of some location.

const reference = new skygear.Geolocation(22.283, 114.15);

const photoQuery = new skygear.Query(Photo);
photoQuery.distanceLessThan('location', reference, 400);

skygear.publicDB.query(photoQuery).then((photos) => {
  console.log(photos);
}, (error) => {
  console.error(error);
});

Geolocation query has distanceGreaterThan function as well.

Sorting records by distance

You can sort the result of the query by distance from a reference location:

photoQuery.addAscendingByDistance('location', reference);
photoQuery.addDescendingByDistance('location', reference);

Querying distance from record geolocation column to given reference point

You can utilize transient fields. Please read more about transient and eager loading in the Queries section.

photoQuery.transientIncludeDistance('location', 'distance', reference);
// 'location' is the key where Geolocation object is stored
// 'distance' is the key where calculated distance will be stored in $transient
// reference is the Geolocation object based on which distance is calculated
skygear.publicDB.query(photoQuery).then((photos) => {
  photos.forEach((photo) => {
    console.log(photo.$transient['distance']);
  });
}, (error) => {
  console.error(error);
});

Auto-Increment sequence fields

Skygear reserves the id field in the top level of all record as a primary key. id must be unique and default to be Version 4 UUID. If you want to auto-incrementing id for display purpose, Skygear provide a sequence for this purpose. The sequence is guaranteed unique. Once a record with sequence id is saved, all the other records will automatically have sequence ids as well.

const note = new Note({
  content: 'Hello World'
});
note.noteID = new skygear.Sequence();

skygear.publicDB.save(note).then((note) => {
  console.log(note.noteID);
}, (error) => {
  console.log(error);
});

• You can omit the noteID on update, the value will remain unchanged.
• All the other Note in the database will now automatically have their noteID as well.
• You can migrate any integer to auto-incrementing sequence.
• Our JIT schema at development will migrate the DB schema to sequence. All noteID at Note will be a sequence type once migrated.

If you wish to override sequence manually, you can do that as well. If the provided noteID is taken by another record, there will be an error; otherwise, the record will be saved and the maximum noteID plus one will be used for the next record.

const note = new Note({
  content: 'Hello World'
});
note.noteID = 43;
skygear.publicDB.save(note);