Moor: Is it possible to observe a table on changes such as CREATE,UPDATE,DELETE?

[richard457]

In laravel we have something called an observer, where you can observe a change to a model table for events such as CREATE,UPDATE,DELETE is there any way of achieving the same with moor.?

[simolus3]

Moor keeps track of changes tables internally, this is needed for stream queries to work. We could expose a stream of changed tables, if that helps. But that wouldn't include what kind of update that was (insert, update, delete).

For a feature like #313, we'd have to add additional information, which could include what kind of change was made.

[simolus3]

In the next moor version, you can use database.listenForTableUpdates() for this purpose. It returns a stream that will emit an item whenever a specified table changes. It supports the following modes:

• Listening for all updates: tableUpdates(const TableUpdateQuery.any) (the default)
• Listening on one table: tableUpdates(TableUpdateQuery.onTable(users))
• Listening on one table a specific kind of update: tableUpdates(TableUpdateQuery.onTable(users, kind: UpdateKind.delete))
• Multiple TableUpdateQueries can also be merged by using TableUpdateQuery.allOf(). The util factory TableUpdateQuery.onAllTables(List<Table>) can be used to listen on all updates across multiple tables.

[richard457]

Is this version on https://pub.dev? what is the version number thank you so much for your good work, I appreciate

[simolus3]

Implementing this required some breaking changes, so it will be made available with moor 3.0, which is not yet on pub.
I can release a beta at the end of this week if that helps.

[richard457]

It will help a lot thank you once again.

[richard457]

any update about new release?

[simolus3]

You can use a beta version of moor 3.0 by adding this to your pubspec:

dependency_overrides:
  moor:
    git:
      url: https://github.com/simolus3/moor.git
      ref: beta
      path: moor
  moor_ffi:
    git:
      url: https://github.com/simolus3/moor.git
      ref: beta
      path: moor_ffi
  moor_generator:
    git:
      url: https://github.com/simolus3/moor.git
      ref: beta
      path: moor_generator
  sqlparser:
    git:
      url: https://github.com/simolus3/moor.git
      ref: beta
      path: sqlparser

I know it's a bit of a hassle, but maintaining dev releases on pub across multiple packages is too much work to be feasible.

[richard457]

In the next moor version, you can use database.listenForTableUpdates() for this purpose. It returns a stream that will emit an item whenever a specified table changes. It supports the following modes:

• Listening for all updates: tableUpdates(const TableUpdateQuery.any) (the default)
• Listening on one table: tableUpdates(TableUpdateQuery.onTable(users))
• Listening on one table a specific kind of update: tableUpdates(TableUpdateQuery.onTable(users, kind: UpdateKind.delete))
• Multiple TableUpdateQueries can also be merged by using TableUpdateQuery.allOf(). The util factory TableUpdateQuery.onAllTables(List<Table>) can be used to listen on all updates across multiple tables.

A full example will be much appreciated!

[richard457]

I assume that this should be in Dao and call the DAO i.e in DAO I should have a method like this Stream<Null> getStockByVariantStream() { return tableUpdates(const TableUpdateQuery.any()); }

[simolus3]

Stream<Null> getStockByVariantStream()

I assume stockByVariant is some kind of table? In that case you could use TableUpdateQuery.onTable(stockByVariant).

A full example will be much appreciated!

Anything specific you want to achieve? I could give an example based on that.