how i can get data from Cassandra using value
posts = {
'1': { //this post id
'user_id': '4',
'body': 'This is awesome!',
},
}
i cen get the post using post id
can i get posts related to certain user
i mean get post related to user_id=4 like an example (query using user_id attribute)
regrads
For that you will need to maintain your own (secondary) index.
e.g
userIds = {
'4': { //this user id
'post_id': '1'
},
}
Related
Looking to construct a query against a firestore collection ('parent') where the documents have a nested map (2 logical levels deep). Specifically when the first map has dynamic keys which are not known at the time of running the query. As an example:
Document 1
{
codes: {
abc: {
id: 'hi'
},
def: {
id: 'there'
}
}
}
Document 2
{
codes: {
ghi: {
id: 'you'
},
zmp: {
id: 'guys'
}
}
}
What I would like to do is have a WHERE clause that takes a wildcard for a key in the document. ie.
firestore.collection('parent').WHERE('codes.*.id', '==', 'there')
// Results in Document 1
or
firestore.collection('parent').WHERE('codes.*.id', '==', 'you')
// Results in Document 2
Is there any way to achieve this behavior without having to resort to generating subcollection documents to be used for indexing, or polluting the document itself with a second map that maps ids to codes.
== Not ideal solution 1 (subcollections) ==
Build out the server so that when these documents are filed, a subcollection ('child') is maintained with documents that contain the related information. As an example filing Document 1 above would require filing two documents in the child subcollection:
{
id: 'hi'
code: 'abc'
}
{
id: 'there'
code: 'def'
}
Now we can query for the id we want, and get the parent reference, and follow that all the way back to the parent...
firestore.collectionGroup('child').where('id', '==', 'there')
.get()
.then(snapshot => {
for(const doc of snapshot.docs) {
return doc.ref.parent.parent
}
return Promise.reject('no parents, how sad.')
})
.then(ref => ref.get())
.then(snapshot => snapshot.data())
.then(parent => {
// Thank goodness, the parent is Document 1!
}
The downside to this is maintenance of the sub collections, as well as a number of extra operations against firestore.
== Not ideal solution 2 (model pollution) ==
Another way to achieve this is to implement another map or an array in the document itself which simply contains the ids which would then let us query on those values. ie
{
codes: {
abc: {
id: 'hi'
},
def: {
id: 'there'
}
},
codeids:['hi','there']
}
Although this is easy to query:
.WHERE('codeids', 'ARRAY CONTAINS', 'hi')
I don't like the idea of adding fields that are not meaningful to the consumer of the document (the purpose of the field only being to facilitate a documents ability to be queried due to system constraints)
Open to suggestions!
I'm working on contentful to create blog posts.
I have created a field named with category with dropdown data, like the below image.
I have created more blogs for each categories (Ex: game has 5 blogs, Tour has 10 blogs and etc).
I want to show the list of all categories with content counts,
Is there any possible to get all of the categories with content count? ( I can get it by getting all blogs using this query
const res = ContentfulService.getEntries({ content_type: 'blog'})
then I grouped with category, but to get the category only, I don't want to get all of the blogs.)
Please let me know if there is a solution.
Thanks
The only way to do this through the API would be to make a request for each category and look at the total property of the response and that would be less efficient than what you're already suggesting.
https://cdn.contentful.com/spaces/{space_id}/environments/{environment_id}/entries?access_token={access_token}&content_type={content_type}&fields.category[in]={categoryValue}
I have achieved that using graphQL,
const query =
{
categoryCollection
{
items{
linkedFrom {
blogCollection {
total
}
}
name:category
sys {
id
}
}
}
}
let categories = await fetch(https://graphql.contentful.com/content/v1/spaces/${spaceId}, {
method: 'POST',
headers: {
'Content-Type': 'application/json',
// Authenticate the request
Authorization: Bearer ${accessToken},
},
// send the GraphQL query
body: JSON.stringify({ query }),
})
i'm having trouble with node & knex.js
I'm trying to build a mini blog, with posts & adding functionality to add multiple tags to post
I have a POST model with following properties:
id SERIAL PRIMARY KEY NOT NULL,
name TEXT,
Second I have Tags model that is used for storing tags:
id SERIAL PRIMARY KEY NOT NULL,
name TEXT
And I have many to many table: Post Tags that references post & tags:
id SERIAL PRIMARY KEY NOT NULL,
post_id INTEGER NOT NULL REFERENCES posts ON DELETE CASCADE,
tag_id INTEGER NOT NULL REFERENCES tags ON DELETE CASCADE
I have managed to insert tags, and create post with tags,
But when I want to fetch Post data with Tags attached to that post I'm having a trouble
Here is a problem:
const data = await knex.select('posts.name as postName', 'tags.name as tagName'
.from('posts')
.leftJoin('post_tags', 'posts.id', 'post_tags.post_id')
.leftJoin('tags', 'tags.id', 'post_tags.tag_id')
.where('posts.id', id)
Following query returns this result:
[
{
postName: 'Post 1',
tagName: 'Youtube',
},
{
postName: 'Post 1',
tagName: 'Funny',
}
]
But I want the result to be formated & returned like this:
{
postName: 'Post 1',
tagName: ['Youtube', 'Funny'],
}
Is that even possible with query or do I have to manually format data ?
One way of doing this is to use some kind of aggregate function. If you're using PostgreSQL:
const data = await knex.select('posts.name as postName', knex.raw('ARRAY_AGG (tags.name) tags'))
.from('posts')
.innerJoin('post_tags', 'posts.id', 'post_tags.post_id')
.innerJoin('tags', 'tags.id', 'post_tags.tag_id')
.where('posts.id', id)
.groupBy("postName")
.orderBy("postName")
.first();
->
{ postName: 'post1', tags: [ 'tag1', 'tag2', 'tag3' ] }
For MySQL:
const data = await knex.select('posts.name as postName', knex.raw('GROUP_CONCAT (tags.name) as tags'))
.from('posts')
.innerJoin('post_tags', 'posts.id', 'post_tags.post_id')
.innerJoin('tags', 'tags.id', 'post_tags.tag_id')
.where('posts.id', id)
.groupBy("postName")
.orderBy("postName")
.first()
.then(res => Object.assign(res, { tags: res.tags.split(',')}))
There are no arrays in MySQL, and GROUP_CONCAT will just concat all tags into a string, so we need to split them manually.
->
RowDataPacket { postName: 'post1', tags: [ 'tag1', 'tag2', 'tag3' ] }
The result is correct as that is how SQL works - it returns rows of data. SQL has no concept of returning anything other than a table (think CSV data or Excel spreadsheet).
There are some interesting things you can do with SQL that can convert the tags to strings that you concatenate together but that is not really what you want. Either way you will need to add a post-processing step.
With your current query you can simply do something like this:
function formatter (result) {
let set = {};
result.forEach(row => {
if (set[row.postName] === undefined) {
set[row.postName] = row;
set[row.postName].tagName = [set[row.postName].tagName];
}
else {
set[row.postName].tagName.push(row.tagName);
}
});
return Object.values(set);
}
// ...
query.then(formatter);
This shouldn't be slow as you're only looping through the results once.
I have an axios.post() request configured to update a document in my MongoDB collection by sending current state, updated by textfields.
I have my state initially setup to null:
this.state = {
editedCustomer: {
name: null,
surname: null,
alias: null,
email: null,
phoneNo: null,
_id: null
},
}
These values are updated directly from text fields, so whenever a textfield receives input it updates the state, which is then sent with axios like this:
axios.patch(`${APIURL}/customers/updateCustomer`, {
'name': this.state.editedCustomer.name,
'surname': this.state.editedCustomer.surname,
'alias': this.state.editedCustomer.alias,
'email': this.state.editedCustomer.email,
'phoneNo': this.state.editedCustomer.phoneNo,
'_id': this.state.editedCustomer._id
})
However, my problem is, if I only update some fields (say I only wanna update the customer's name), the rest of these fields are being posted to my backend as null and my database being populated with the updated values, with null now replacing the rest of the fields.
Is there any way to only post non-null values with axios, or should the change be in my /updateCustomer route within my backend. Thanks :)
Axios is sending null because if you're updating only certain values, the other values that are not being supplied are null.
So what you should do is in your /updateCustomer route in your backend, you only update the values that are passed in from axios instead of updating the whole object.
You should just map over that Object using Object.keys and "filter" the values that are null
let data = {};//<- Data to send with Axios
Object.keys(this.state.editedCustomer).map((key) => {
if(editedCustomer[key]) {
data[key] = editedCustomer[key]
}
});
const dataToSend = JSON.stringify(data);
then you just post your dataToSend with Axios/fetch...
I'm building an API using node express and mongodb, with mongoose.
I have a post resource that handles user posts, and would like to be able to perform various queries on the post resource.
For instance I have a functions as that returns all posts as follows:
// Gets a list of Posts
exports.index = function(req, res) {
console.log(req.query);
Post.findAsync()
.then(mUtil.responseWithResult(res))
.catch(mUtil.handleError(res));
};
I looking for a good way of processing any additional query params that might come with the request.
/posts will return all posts, but /posts?user=12 will return posts by user with id 12 and /posts?likes=12 will return posts with 12 or more likes.
How can I check for and apply the these query params to filter and return the results since they may or may not be present.
Thanks ;)
If user=12 means "users with id 12", how does likes=12 mean "likes greater than 12"? You need to be more descriptive with your queries. You can do that by passing an array of objects. Send your query in a way that can be interpreted like this:
var filters = [
{
param: "likes",
type: "greater"
value: 12
},
{
param: "user",
type: "equal",
value: "12"
}]
var query = Post.find();
filters.forEach(function(filter) {
if (filter.type === "equal") {
query.where(filter.param).equals(filter.value);
}
else if (filter.type === "greater") {
query.where(filter.param).gt(filter.value);
}
// etc,,,
})
query.exec(callback);