I have the documents of the following prototype:
{
title: "HD8200 DLP Projector",
normal_price: 4999.99,
specifications: [
{
ov: "HD (1920 x 1080)",
fn: "Resolution (Native / Max)",
o: 7,
f: 211
},
{
ov: "20000",
fn: "Contrast Ratio",
o: 15,
f: 225
}
]
}
I'm looking to create a list of filters for this product database, based on the specifications.
How can I get a list of option IDs (o) mapped to their product counter, for each field (f)?
Let's assume I need to achieve this for a specific list of field IDs (say, 211 and 225).
Write a mapper to take one document per map() call and write out a record for each option. The record key would be the field ID and the value would be a concatenation of a flag "1", the product title and option ID.
Write another mapper to read the list of id's and to write out a record with the same format: the key is the field ID and the value is a concatenation of a flag "0" and two empty strings.
Write a Reducer to read in the records written by the two mappers. Each call to reducer() will pass in all records written for a given field. If one of those records has a "0" flag then that field was one of the fields you're interested in. Only then would you write out a record for each record with a "1" flag. The key is the product title and the value is the option id.
Define your first job driver class to use the two mappers and the one reducer. This step will come up with pairs of product-options for the field id's you specify. You'll need a second job to gather the options by product, or vide versa.
Related
I am working on implementing grouping w/ the Server Side Row Model. I need to generate an appropriate ID for the intermediate group rows. For example, if I group by Status then I would have intermediate rows representing each Status (NEW, IN PROGRESS, COMPLETE, etc). I need to come up with a unique ID for these rows (but preferable something deterministic if they need to be accessed/updated later).
The getRowId function is passed an object that contains things like the row's data, the previous parent group values, a reference to the api, etc.
What I would ideally like to know is the current list of group fields... I have all of the values readily accessible, but I don't know what field the current row is being grouped by - else I could just go grab that field from the row's data to use as part of the row id...
Is there any good way to acquire this information?
The columnApi exposes the 'getRowGroupColumns' function from which the field property can be deduced:
getRowId: ({ columnApi, data, level, parentKeys = [] }) => {
const groupColumns = columnApi.getRowGroupColumns();
if (groupColumns.length > level) {
const field = groupColumns[level].getColDef().field;
return [...parentKeys, data[field]].join('-');
}
return [...parentKeys, data.athlete, data.year];
},
I am listing users in a CustomScrollView/SliversList,ListTiles. I have a String field in my firestore and only want to return ListTile of a user, where his String field contains specific words (more than 2). For example, the users fields contain: "Apples, Ice, Bananas, Soup, Peaches, e.g...." and i want to list all users which have apples and bananas inside the field. how can i achieve this?
The only way to do it at the moment (with the way you have it set up) is actually pulling the value and doing a string "contains" or splitting the string into an array and check whether the value is within that array, otherwise I'd advise to refactor that field and make it into an array, that way you can perform a native arrayContainsAny against your field.
For you it will look like this (with your current implementation):
// ... after pulling all users' documents
// let's say your field is called 'foodField':
var criteria = 'Banana';
var fieldContent = doc.data()['foodField'];
// you can either do this:
if (fieldContent.toLowerCase().contains(criteria.toLowerCase())) {
// ...
}
// or you can tokenize it depending on your purposes...
var foodTokens = fieldContent.split(',').map((f) => f.toLowerCase());
if (foodTokens.contains(criteria.toLowerCase()) {
// ...
}
If your Firestore field was an array type, then you could've just done that, while querying:
FirebaseFirestore.instance.collection('users').where('foodField', arrayContainsAny: ['Banana', 'Apples'])
Which then would give you only the users whose foodField contain that value.
As you can see from previous questions on querying where text contains a substring, Firestore does not currently support such text searches. The typical solutions are to either perform part of your filtering in your application code as Roman answered, or to integrate a third-party full-text search solution.
In your specific case though, your string seems to be a list of words, so I'd recommend considering to change your data model to an array of the individual values in there:
"foodFields": ["Apples", "Ice", "Banana", "Soup", "Peaches"]
You can then use array field operators in the query.
While there is no array-contains-all operator, using array-contains you can at least filter on one value in the database, and with array-contains-any you can do on OR like condition.
Another data model would be to store the individual values in a map field with value true for each of them:
"foodFields": {
"Apples": true,
"Ice": true,
"Banana": true,
"Soup": true,
"Peaches": true
}
With such a structure you can perform an AND like query with:
collectionRef
.where('foodFields.Apples', isEqualTo: true)
.where('foodFields.Bananas', isEqualTo: true)
We have following structure in MongoDB documents.
{
"id":"1111",
"keys":[
{
"name":"Country",
"value":"USA"
},
{
"name":"City",
"value":"LongIsland"
},
{
"name":"State",
"value":"NewYork"
}
]
}
Now using Springframework Query object, I figured out a way to pull the details using below syntax
query.addCriteria(
Criteria.where("keys.value").is(countryparam).
andOperator(
Criteria.where("keys.value").is(stateparam)
)
);
Two issue with this query model.
First issue is it is irrelevant if countryparam and stateparam are actually meant to match Country key name and State key name respectively. If just the values matches, the query returns the document. Means, if I have Country and City params, this just works if user passes Country and City values, even if they are swapped. So how can I exactly compare City to cityparam and State to Stateparam?
More complexity is if I have to extract the document basing on multiple key value pairs, I should be correspondingly able to match key name with respective value and query the document. How can I do this?
Thanks in advance!
I want to put the query result from one collection in a variable and use it as input for query in another collection. The queries look like this as follows:
Query 1:
var ID=db.User.findOne({Name:"Ivan"}, {ID: 1});
db.Artists.find({"Listeners.ID":ID});
Query 2:
var Friends=db.Users.find({Friends:x});
//Users.Friends is an array of interger identifier for User
db. Artists.find({"Listeners.ID":{$in:Friends}});
But they all don't work. How to write the right one?
The query db.User.findOne({Name:"Ivan"}, {ID: 1}); does not return a single value, it returns the document, reduced to the field you requested. What you get is an object, with two fields: _id (because you didn't explicitly exclude it) and ID (when it exists in the document). Your var ID looks like this:
{
_id:ObjectId(<long hex string>),
ID:<value>
}
So when you want to query by the ID value, you need to specify it:
db.Artists.find({"Listeners.ID":ID.ID});
Regarding your second query: when you use find instead of findOne you get a cursor object which can then be used to retrieve the individual documents using cursor.next() or cursor.toArray().
If you only know the key name (say "nickname"), but not the exact path to that key in the object.
e.g. nickname may be at the first level like:
{"nickname":"Howie"}
or at the second level:
{"user":{"nickname":"Howie"}}
Is it possible to query for nickname equal "Howie" that would return both documents?
Unfortunately there is no wild card that allows you to search for a field at any level in the db. If the position is not relevant and you can modify the document structure you have 2 choices here. You can store your document as
{ fieldname:"nickname", value : "Howie" }
{ fieldname:"user/nickname", value: "Howie" }
You can then query using
db.so.find({fieldname:/nickname/, value:"Howie"})
Alternatively you can store as
db.so.insert({value:"Howie", fieldpath:["nickname"]})
db.so.insert({value:"Howie", fieldpath:["user", "nickname"]})
The advantage with the second approach is that you can now index {fieldpath:1, value:1} and a query on it such as
db.so.find({fieldpath:"nickname", value:"Howie"})
will be an indexed query.