Coverage increased (+0.06%) to 96.4% when pulling eb765b1d323d0f3ae6d5ce714014cd3097ac38da on feature/association-query into ce214b2 on master.

Coverage increased (+0.06%) to 96.4% when pulling 8c97a5bf0bd34d179e98a2bd0138b8eaa394ac07 on feature/association-query into ce214b2 on master.

这个是已经实现好了呀？

@chuan6 @Miloas 之后你们先帮我review下这个PR啦~~

@Saviio 嗯嗯，代码看过，但还没理解这个 PR 要达到的效果，今天再看看 👌

达到的效果是:

transform

{
  fields: [....],
  where: {
    'creator.gender': 'male' 
  }
}

to

SELECT 
  _id,
  Member.id,
  Member.name,
  Member.gender
FROM Message 
JOIN Member ON Message.creatorId = Member.id
WHERE Member.gender = 'male'

@Brooooooklyn 我第一次注意到 createPredicate 这个函数，根据目前的实现，它的作用应该已经被现在的 PredicateProvider （可以处理空的 null 或 undefined 的 clause）代替了，还需要保留它吗？

可以保留，配合 tryCatch 作为:

try {
  new PredicateProvider(xxxxx).getPredicate()
  // success logic
} catch (e) {
  // error logic
}

的语法糖

Coverage decreased (-0.06%) to 96.28% when pulling 4ef39feb47ef967faaced5ca1755d3e79c178461 on feature/association-query into ce214b2 on master.

Coverage increased (+0.08%) to 96.413% when pulling fa72de7d08cd9b45f2d53ed11108f4f8e0d630fa on feature/association-query into ce214b2 on master.

我现在的做法是:

1. 在 JoinInfo 中构建一个 tablesStructure, 它是这样的类型:

{
  [index: string]: { 
    table: lf.schema.Table
    contextName: string
  }
}

2. 使 buildSelector 中 predicateProvider.getPredicate() 变成 lazy 的，即: 不是在 build joinInfo 的时候就 getPredicate，而是在从 joinInfo 中 build joinQuery 的时候再 getPredicate , 这个时候可以拿到整条查询语句的 tablesStructure，比如:

{
  'Task#1': {
     table: tableClass, // alias Task#1,
     contextName: 'Task#1'
   },
   'Task#1@project': {
      table: tableClass, // alias Project#1
      contextName: Project#1
    },
    'Project#1@organization': {
      table: tableClass, // alias Organization#1
      contextName: Organization#1
    }
}

3. 让一条 get/upsert 语句中所有的 joinPredicate 和 wherePredicate 共用这个 tablesStructure, 然后到 PredicateProvider 中根据 meta 解析出 predicate

这样做有一个问题就是，当 query 的 predicate 中指定了某个关联的条件，但 fields 中并不包含这个关联的时候会构建不出 tablesStructure, 比如:

Database.get('Task', {
  fields:  ['_id'],
  where: {
    'project.organization._id': 'xxxx'
  }
})

具体表现就是 skip 掉的那个测试

Coverage increased (+0.08%) to 96.413% when pulling 49f780161e544c70a93f43884125f359b9b04515 on feature/association-query into ce214b2 on master.

ready

Coverage decreased (-0.08%) to 96.266% when pulling 77e98bd on feature/association-query into a7e2496 on master.

Coverage increased (+0.2%) to 96.504% when pulling 68fb8fe on feature/association-query into a7e2496 on master.

Coverage increased (+0.4%) to 96.7% when pulling 541b338 on feature/association-query into a7e2496 on master.

Coverage increased (+0.4%) to 96.7% when pulling 1bdb3a0 on feature/association-query into a7e2496 on master.

Coverage increased (+0.1%) to 96.487% when pulling ac32a6d on feature/association-query into a7e2496 on master.

Coverage increased (+0.1%) to 96.487% when pulling d78d3a1 on feature/association-query into a7e2496 on master.

Coverage increased (+0.2%) to 96.532% when pulling ba7a13a on feature/association-query into a7e2496 on master.

Coverage increased (+0.2%) to 96.532% when pulling 9e7db4a on feature/association-query into a7e2496 on master.