How can I structure my database in Firebase for search for recipes? Each recipe have some ingridients. I need to search for recipes. If the query contains several matching ingredients, I need to output a recipe containing a matching value.
It is my strucuture of database now :
{
"Recepts" : [ {
"Ingridients" : [ "Carrot", "Sugar" ],
"Name" : "Carrot Salad"
}, {
"Ingridients" : [ "Orange", "Milk" ],
"Name" : "Orange Milk"
} ]
}
If this is correct, how can I do a query for my database?
It is a best practice to avoid using array and save list of data as map instead.
To search for recipes having an ingredient, you could use orderByChild together with equalTo the ingredient you are looking for.
The data structure would be
{
"Recipes" : {
"CarrotSalad": {
"Ingredients" : {
"Carrot": true,
"Sugar": true
},
"Name" : "Carrot Salad"
},
....
}
}
Related
I have the collection that stores documents per some execution Flow.
Every Process includes "processes" and each process includes steps.
So I end up with a 'flows' collection that has documents that look like this:
{
"name" : "flow1",
"description" : "flow 1 description",
"processes" : [
{
"processId" : "firstProcessId",
"name" : "firstProcessName",
"startedAt" : null,
"finishedAt" : null,
"status" : "PENDING",
"steps" : [
{
"stepId" : "foo",
"status" : "PENDING",
"startedAt" : null,
"finishedAt" : null
},
{
"stepId" : "bar",
"status" : "PENDING",
"startedAt" : null,
"finishedAt" : null
}
...
]
},
{
"processId" : "secondProcessId",
"name" : "secondProcessName",
"startedAt" : null,
"finishedAt" : null,
"status" : "PENDING",
"steps" : [
{
"stepId" : "foo",
"status" : "PENDING",
"startedAt" : null,
"finishedAt" : null
},
{
"stepId" : "xyz",
"status" : "PENDING",
"startedAt" : null,
"finishedAt" : null
}
...
]
}
}
A couple of notes here:
Each flow contains many processes
Each process contains at least one step, it is possible that in different processes the steps with the same id might appear (id is something that the programmer specifies),
It can be something like "step of bringing me something from the DB", so this is a kind of reusable component in my system.
Now, when the application runs I would like to call DAO's method like
"startProcess", "startStep".
So I would like to know what is the correct query for starting step given processId and steps.
I can successfully update the process description to "running" given the flow Id and the process Id:
db.getCollection('flows').updateOne({"name" : "flow1", "processes" : {$elemMatch : {"processId" : "firstProcessId"}}}, {$set: {"processes.$.status" : "RUNNING"}})
However I don't know how to update the step status given the flowId, process Id and step Id, it looks like it doesn't allow multiple "$" signs in the path:
So, this doesn't work:
db.getCollection('flows').updateOne({"name" : "flow1", "processes" : {$elemMatch : {"processId" : "firstProcessId"}}, "processes.steps.stepId" : {$elemMatch : {"stepId" : "foo"}}}, {$set: {"processes.$.steps.$.status" : "RUNNING"}})
What is the best way to implement such an update?
To update the document in multi-level nested array, you need $[<identifier>] filtered positional operator and arrayFilters.
And the processes and processes.steps.stepId filter in the match operator can be removed as the filter is performed in arrayFilters.
db.collection.update({
"name": "flow1"
},
{
$set: {
"processes.$[process].steps.$[step].status": "RUNNING"
}
},
{
arrayFilters: [
{
"process.processId": "firstProcessId"
},
{
"step.stepId": "foo"
}
]
})
Sample Mongo Playground
Reference
Update Nested Arrays in Conjunction with $[]
As you mentioned it does not work with multiple arrays, straight from the docs:
The positional $ operator cannot be used for queries which traverse more than one array, such as queries that traverse arrays nested within other arrays, because the replacement for the $ placeholder is a single value
I recommend you use arrayFilters instead, it's behavior is much clearer especially when working with nested structures:
db.collection.updateMany(
{
"name": "flow1",
"processes.processId": "firstProcessId",
"processes.steps.stepId": "foo"
},
{
$set: {
"processes.$[process].steps.$[step].status": "RUNNING"
}
},
{
arrayFilters: [
{
"process.processId": "firstProcessId"
},
{
"step.stepId": "foo"
}
]
})
Mongo Playground
I want to delete the data on the date basis(which is present inside the array). This is how my mongo document looks like.
{
"_id" : ObjectId("5d3d94df83f68f8bf751f367"),
"branchName" : "krishYogaCenter",
"Places" : [
"Pune",
"Bangalore",
"Hyderabad",
"Delhi"
],
"rulesForDateRanges" : [
{
"fromDate" : ISODate("2019-01-07T18:30:00.000Z"),
"toDate" : ISODate("2019-03-06T18:30:00.000Z"),
"place" : "Delhi",
"ruleIds" : [
5,
6,
7
]
},
{
"fromDate" : ISODate("2019-03-07T18:30:00.000Z"),
"toDate" : ISODate("2019-05-06T18:30:00.000Z"),
"place" : "Hyderabad",
"ruleIds" : [
1,
2
]
}
],
"updatedAt" : ISODate("2019-07-28T12:31:35.694Z"),
"updatedBy" : "Theia"
}
Here, if "toDate" is less than today I want to delete that object from the array "rulesForDateRanges". Searched on the google but did not get any way to do this in morphia.
If this date was not present internally in the array object then I could have used "delete document where the date is less than today". Here I want to remove that object from the array which is in no longer use, and if the array "rulesForDateRanges" becomes empty in that case only want to delete the whole document.
I am using morphia. Please suggest the way to do this in morphia or the query to do this.
Searched on google got this: We can get the document one by one from the collection using query and do UpdateOperation over that document. But here I have to perform updateOperation for each and every document.
Hi I am using spring data mongo, I need to fetch data based on multiple where condition. The problem I have when I want to apply a where clause to a list in a list.
For example
{
"_id" : ObjectId("5982bf9339f3c92b84be4737"),
"_class" : "com.paladion.payment.model.GroupQuestionMapping",
"saqID" : "SAQ A",
"saqVersion" : "3",
"questionTab" : {
"Secure Network" : [
{
"number" : "2.1 (a)",
"question" : "Are vendor-supplied"
"description" : "<ul><li>Review"
},
{
"number" : "2.1 (b)",
"question" : "Are unnecessary"
"description" : "<ul><li>Review policies
}
],
"Access Control" : [
{
"number" : "2.1 (a)",
"question" : "Are vendor-supplied"
"description" : "<ul><li>Review"
},
{
"number" : "2.1 (b)",
"question" : "Are unnecessary"
"description" : "<ul><li>Review policies
}
]
}
}
Over here I need to fetch data where saqId is SAQ A and saq Version is 3 and questionTab is secure network.
I have problem in applying criteria on questionTab.
my code:
Query query = new Query();
query.addCriteria(Criteria.where("saqtype").is(saqType));
query.addCriteria(Criteria.where("saqversion").is(saqVersion));
query.addCriteria(/* criteria on questionTab */);
query.addCriteria(Criteria.where("questionTab.Secure Network").exists(true));
Thing to note is that it will bring you the full document based on criteria, so you would have to filter out other type of questionTab from document.
Other way is aggregation but then I think processing on application layer might be preferable.
My mongo collection has entries in the following format
{
"myobj" : {
"objList" : [
{ "location" : "Texas" },
{ "location" : "Houston"},
{ "name":"Sam" }
]
},
"category" : "cat1"
}
{
"myobj" :
{
"objList" : [
{ "location" : "Tennesy" },
{ "location" : "NY"},
{ "location" : "SF" }
]
},
"category" : "cat2"
}
I want to extract the "**category**" where location is "Houston". In case of simple JSON object I have to just pass it as query like:
BasicDBObject place = new BasicDBObject();
place.put("location", "Houston");
But in case of nested JSON I don't know how to pass it as a query and get the appropriate category. ie If I pass my location as"Houston" then it should return it's appropriate category "cat1"...i hope my question is clear now....
Ok, you have your documents:
db.coll1.insert({
"myobj" : {
"objList" : [
{ "location" : "Texas" },
{ "location" : "Houston"},
{ "name":"Sam" }
]
},
"category" : "cat1"
})
and
db.coll1.insert({
"myobj" : {
"objList" : [
{ "location" : "Tennesy" },
{ "location" : "Houston"},
{ "location" : "SF" }
]
},
"category" : "cat1"
})
Now you can find what you want using the dot operator:
db.coll1.find({"myobj.objList.location": "Texas"}).pretty() will return one object which has Texas
db.coll1.find({"myobj.objList.location": "SF"}).pretty() will return one object which has SF
db.coll1.find({"myobj.objList.location": "Houston"}).pretty() will return both objects
And now I hope you will be able to write it in Java. I have never used Java, but based on this question you can do something like this. If it will not work, just look how to use dot operator in java driver for mongo:
DBCursor cursor = coll1.find(new BasicDBObject("myobj.objList.location", "Texas"));
P.S. you told, that you wanted to retrieve category. In such a way, you will need to use a projection db.coll1.find({<the query I provided}, {category: 1, _id: 0})
I have a json object as following:
{ "_id" : ObjectId("508806803bb97dc546e6f307"), "user_name" : "user1", "user_id" : 45645645, "likes" : [ { "event_id" : NumberLong("4578541212") },{ "event_id" : NumberLong("4578541213") } ], "dislikes" : [ ] }
I'm trying to delete specific event within likes array via java drivers
tried doing this first in shell:
> db.users.update( {'likes.event_id' : 4578541212}, { '$unset':{'likes.event_id'
:1}})
with no luck...how can I manage doing that?
If you want to just remove the event_id field from the array element:
db.users.update( {'likes.event_id' : 4578541212}, {'$unset':{'likes.$.event_id' :1}})
Use the $pull operator to delete the element:
db.users.update({'likes.event_id': 4578541212}, {'$pull':{likes: {event_id: 4578541212}}})