Is db.rel.find() have an option for paging?

[Murugan1778]

Hi Guys,
I am using relational pouch for data fetching. How can i implement the data fetch by paging using db.rel.find()

[broerse]

Perhaps use startkey and limit

https://github.com/pouchdb-community/relational-pouch#dbrelfindtype-options

[Murugan1778]

I have used auto generated id(UUID). So how can I use start key?

[broerse]

In Ember Pouch we use startkey 'post_2_' and endkey 'post_3_' because we know our ID's always start with post_2_ for the post model. The startkey does not have to exist so you need to write something you know will come before your first real ID.

[Murugan1778]

Consider like this, I have 10 records with following id structure post_2_randomUUID. If I want to fetch the records by 2 batch, for each batch I need 5 records. How can I implement this?

[broerse]

Start with startkey post_2_ and limit 6. This way you know what your next startkey is.

[Murugan1778]

In this way I don't know the next start key because post_2 is randomUDID. Then how can I call next batch?

[broerse]

? I don't seem to understand you. You know the next start key because it is the same as the ID in the last record.

[Murugan1778]

Ok. This is my sample code

this.db.rel.save('post', { name: 'prabu', email: '[email protected]'})
this.db.rel.save('post', { name: 'murugan', email: '[email protected]'})

It will store in following format in pouchdb

{
"_id": "post_2_047E96BB-39BC-582F-A9B1-53385A9A4B93",
"_rev": "1-27f0ff931f544624863db976ce7785c8",
"data": {
"name": "parbu",
"email": "[email protected]"
}
}

{
"_id": "post_2_0f3076f044e8949b970e68a12d25a505",
"_rev": "1-ebdc46f142927ba11b4fcb49318c82cd",
"data": {
"name": "murugan",
"email": "[email protected]"
}
}

If I try to fetch like below format not working. Give empty response.

return this.db.rel.find('post',{startkey: 'post', limit: 2}).then(res => {
            console.log(res)
        })

If I change like this it will working. Give two docs in response.

return this.db.rel.find('post',{startkey: '047E96BB-39BC-582F-A9B1-53385A9A4B93', limit: 2}).then(res =>{
            console.log(res)
        })

So how I pass start key? I don't know the id first time. Only I know post.

[broerse]

Use 'post_2_' the first time. As I said "The startkey does not have to exist" it just has to come before the first posible key.

[Murugan1778]

thank you. I tried this also but it returns empty response only.

return this.db.rel.find('post',{startkey: 'post_2_', limit: 2}).then(res => {
           console.log(res)
       })

[broerse]

Sorry I am working to much with pouchdb-find I forgot you had to just write null

See:

var PouchDB = require('pouchdb');
PouchDB.plugin(require('relational-pouch'));

var db = new PouchDB('https://martinic.couchcluster.com/bloggr');

db.setSchema([
  {
    singular: 'post',
    plural: 'posts',
    relations: {
      author: {belongsTo: 'author'}
    }
  },
  {
    singular: 'author',
    plural: 'authors',
    relations: {
      posts: {hasMany: 'post'}
    }
  }
]);

db.rel.find('post',{startkey: null, limit: 6}).then(res => {
  console.log(res)
}).catch(err => {
  console.log ('error', err);
});

[Murugan1778]

Thanks it's working now. How to pass selector and sorting in this way?