Create many to many instance with id?

[seanchenca]

Hi,

Let say I have two classes:

@Entity('resource')
class Resource extends EntBase {

  @Column({ type: 'varchar', length: 64 })
  title: string

  @ManyToMany(type => Topic, topic => topic.resources)
  @JoinTable({ name: 'resource_topic' })
  topics: Topic[]
}

@Entity('topic')
class Topic extends EntBase {

  @Column({ type: 'varchar', length: 64 })
  topic: string

  @ManyToMany(type => Resource, resource => resource.topics)
  resources: Resource[]
}

and I would like to create a new Resource with two topics, and I already know the ids of the two topic (suppose they are 1, and 2), I am assuming I have to do:

const topic1 = awiat topicRepo.findById(1);
resource.topics.push(topic1);
const topic2 = await topicRepo.findById(2);
resource.topics.push(topic2);
resourceRepo.create(resource);

is it possible to save the Resource without creating instances of Topic? or do I have to manipulate the 'resource_topic' table manually?

btw, if I omit the {type: 'varchar', length: 64} for the topic column and leave it just:

@Column()
topic: string

I got an error:

sqlMessage: 'You have an error in your SQL syntax; check the manual that corresponds to yourMySQL server version for the right syntax to use near \'NOT NULL, `lang` enum(\'en\', \'fr\') NOT NULL) ENGINE=InnoDB\' at line 1',
[Node]   sqlState: '42000',
[Node]   index: 0,
[Node]   sql: 'CREATE TABLE `topic` (`id` int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT, `createdAt` datetime(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6), `updatedAt` datetime(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6), `version` int(11) NOT NULL, `topic`  NOT NULL, `lang` enum(\'en\', \'fr\') NOT NULL) ENGINE=InnoDB',

looks like the query is not specifying type of topic, I thought typeorm is going to infer that from the string type and make it varchar(255), am I missing some settings?

[pleerock]

Regarding to your question - checkout how to work with relational query builder.

Regarding to your error - did you specify a reflect-metadata properly? Looks like it cannot get type reflection from your properties.

[seanchenca]

thanks @pleerock for pointing out the doc. works perfectly:

      .createQueryBuilder()
      .relation(Resource, 'topics')
      .of(resourceId)
      .addAndRemove([...], [...])

for the error, do you refer to the option in tsconfig.json?:

"emitDecoratorMetadata": true,

I do have this option enabled, or is it something else?

[seanchenca]

hi @pleerock, seems I have some problem with the addAndRemove call. let say originally I have two resources id 1 and 2. resource 1 has topics id 1 and 2, resource 2 has no topic. so the resource_topic table has the following record:

resourceId  |  topicId
----------------------
       1    |      1
       1    |      2

now I want to update resource 2 to have topics id 3 and 4, after I call:

getConnection()
      .createQueryBuilder()
      .relation(Resource, 'topics')
      .of(2)
      .addAndRemove([3, 4], []);

the resource_topic table become:

resourceId  |  topicId
----------------------
       2    |      3
       2    |      4

i.e. the record for resource id 1 are wiped out. the reason I use addAndRemove and passing an empty array for removing ids is because if there were topics associated with resource I would like to remove the original ones

also if I call

getConnection()
      .createQueryBuilder()
      .relation(Resource, 'topics')
      .of(2)
      .addAndRemove([], []);

or

getConnection()
      .createQueryBuilder()
      .relation(Resource, 'topics')
      .of(2)
      .remove([]);

the whole resource_topic table is wiped out and become completely empty too.

could you see what I did wrong here?

[pleerock]

Its not expected behaviour. If you send empty array it should not do anything. Fixed and will be released in 0.1.7