I have added MongoDB as external dictionary, I can retrieve data from mongodb using the below query.
select dictGetString('table', 'field', tuple(toUInt16(4089))) columnName
How to retrieve all records from external dictionary?
You can use a specific database to retrieve data from all dictionaries.
CREATE DATABASE dictionaries ENGINE = Dictionary;
SELECT * FROM dictionaries.<your dictionary name>;
Related
I'm having a Spring application with jOOQ and Postgresql database having a table (issues) with the following two columns:
id (Long)
documents (jsonb[]) <- array of jsonb (not jsonb array)
The document json structure is on the following format:
{
"id": (UUID),
"name": (String),
"owner"; (String)
}
What I want to achieve is to be able to replace documents with matching id (normally only one) with a new document. I'm struggling with the jOOQ or even the plain SQL.
I guess I need to write some plain SQL in jOOQ to be able to do this but that is ok (to a minimum). I had an idea to do the following:
Unnest the document column
Filter out the document that should be updated of the array
Append the document that should be updated
Store the whole array
Raw SQL looks like this but missing the new document to be added:
UPDATE issues SET documents = (SELECT ARRAY_AGG(doc) FROM issues, UNNEST(issues.documents) AS doc WHERE doc->>'id' != 'e4e3422f-83a4-493b-8bf9-37980d532538') WHERE issues.id = 1;
My final goal is to write this in jOOQ and append the document to be replaced. I'm using jOOQ 3.11.4.
You should be able to just concatenate arrays in PostgreSQL:
UPDATE issues
SET documents = (
SELECT ARRAY_AGG(doc) || '{"id":"e4e3422f-83a4-493b-8bf9-37980d532538","name":"n"}'::jsonb
FROM issues, UNNEST(issues.documents) AS doc
WHERE doc->>'id' != 'e4e3422f-83a4-493b-8bf9-37980d532538'
)
WHERE issues.id = 1
Some common array functions will be added to jOOQ in the near future, e.g. array concatenation, but you can get away for now with plain SQL templating I suspect?
I have collection with field price that is of the DataType Decimal. When I use insertMany, how to set it to store in decimal type ?
let data=[{id:'1', price:10}, {id:'2', price:20}]
insertMany(data)
I user meteor and mongo node driver.
To insert multiple document in MongoDB collection you can use the insert method of MongoDB driver for nodejs. Meteor provides rawCollection method to access to the the Collection object corresponding to the collection from the MongoDB driver module which is wrapped by Mongo.Collection.
In your case the query will be like this:
let data=[{id:'1', price:10}, {id:'2', price:20}]
CollectionName.rawCollection().insert(data);
I am new in MongoDB. I am using MongoDB 3.6.3. I have one fields in the document with huge josn data and I don't know all key names present inside JSON data.
Now I want to search documents by the value which will present in any key inside JSON data.
I have tried using this.
db.getCollection('booking').find({'result.important_information': /.*small dogs*/})
But this required key for search But I dont have key name I have to search using the only value.
This question already has an answer here:
Why does mongoose use schema when mongodb's benefit is supposed to be that it's schema-less?
(1 answer)
Closed 5 years ago.
I am a beginner with MongoDB and trying to learn MEAN Stack. So I am using Mongoose as the ORM
I read that MongoDB is a NoSQL database, but while using Mongoose as ORM, I am asked to create a schema first. Why is it so? There shouldn't be a schema ideally as MongoDB is a NoSQL database.
Thanks in advance.
Mongoose is an orm on top of mongodb , if you are using core mongodb you need not create any schema , you can just dump any data you want , but in mongoose you have a schema so that you can i have some basic key value pair for advanced searching and filtering and you can anytime update the schema. Or If you want to go schemaless and dump whatever the response is you can use a schema type like this var someSchema = {data:Object} and drop all your data in this data key and then you can easily extract whatever JSON data is inside your id field.
var mongoose = require('mongoose');
module.exports = mongoose.model('twitter', {
created_at:{
type:Date
},
dump:{
type:Object
}
});
In the above example dump is used to save whatever JSON I get as a response from twitter api and created_at contains only the creating date of tweet , so I have the entire data , but if i want to search tweets of a particular date I can search it using a find query on created_at and this query will be lot faster and here I have a fixed structure and a knowledge about what to expect of a find query each time a run one, So this is one of the benefit of using the mongoose orm i.e I don't lose data but I can maximise my searching ability by creating appropriate keys.
So basically mongoose is an ORM db , it offers you relational db features like creating foreign keys , not strictly foreign keys but you can create something like an id reference to another schema and later populate the field by the id associated parameters when you fetch data using your find query , also a relational schema is easy to manage , what mongoose does is it gives a JSON/BSON based db the power of relational db and you get best of both the world i.e you can easily maintain new keys or you don't need to worry about extracting each and every data from your operation and placing it properly/inserting it , you just need to see that your keys and values match , as well as you have flexibility in update operations while having a schema or table structure.
I am trying to query out the data from my MongoDB database but there are some fields which I would like to omit as MongoDB will query the whole collections with id, n out.
I did this to limit the query but unfortunately only one field could be omitted but not the other which is the 'n' field. How can I omit two fields?
data = collection.find_one({"files_id": file_id},{"_id":0,"data":1})
And I also realized that my query for data has the field name (u'data') too, how can I query it so that it only returns the data? for this case it's a binary data
Example:
{u'data': Binary('\x00\x00\xed\x00\n\x00\x00\xd5\xa9\x00\x000\x00\x00\x00#\x00\x00\x0f\xff\xf0\x00\x0b\x80\x00\x00\x00
Kindly assist thanks!