I've been working on a python3 script that is given an Entity Id as a command line argument. I need to create a query or some other way to retrieve the entire entity based off this id.
Here are some things I've tried (self.entityId is the id provided on the commandline):
entityKey = self.datastore_client.key('Asdf', self.entityId, namespace='Asdf')
query = self.datastore_client.query(namespace='asdf', kind='Asdf')
query.key_filter(entityKey)
query_iter = query.fetch()
for entity in query_iter:
print(entity)
Instead of query.key_filter(), i have also tried:
query.add_filter('id', '=', self.entityId)
query.add_filter('__key__', '=', entityKey)
query.add_filter('key', '=', entityKey)
So far, none of these have worked. However, a generic non-filtered query does return all the Entities in the specified namespace. I have been consulting the documentation at: https://googleapis.dev/python/datastore/latest/queries.html and other similar pages of the same documentation.
A simpler answer is to simply fetch the entity. I.e. self.datastore_client.get(self.datastore_client.key('Asdf', self.entityId, namespace='asdf'))
However, given that you are casting both entity.key.id and self.entityId, you'll want to check your data to see if you are key names or ids. Alternatives to the above are:
You are using key ids, but self.entityid is a string self.datastore_client.get(self.datastore_client.key('Asdf', int(self.entityId), namespace='asdf'))
You are using key names, and entityId is an int self.datastore_client.get(self.datastore_client.key('Asdf', str(self.entityId), namespace='asdf'))
I've fixed this problem myself. Because I could not get any filter approach to work, I ended up doing a query for all Entities in the namespace, and then did a conditional check on entity.key.id, and comparing it to the id passed on the commandline.
query = self.datastore_client.query(namespace='asdf', kind='Asdf')
query_iter = query.fetch()
for entity in query_iter:
if (int(entity.key.id) == int(self.entityId)):
#do some stuff with the entity data
It is actually very easy to do, although not so clear from the docs.
Here's the working example:
>>> key = client.key('EntityKind', 1234)
>>> client.get(key)
<Entity('EntityKind', 1234) {'property': 'value'}>
Related
In case we had the model:
class Publication(models.Model):
title = models.CharField(max_length=30)
class Article(models.Model):
publications = models.ManyToManyField(Publication)
According to: https://docs.djangoproject.com/en/4.0/topics/db/examples/many_to_many/, to create an object we must have both objects saved before we can create the relation:
p1 = Publication(title='The Python Journal')
p1.save()
a1 = Article(headline='Django lets you build web apps easily')
a1.save()
a1.publications.add(p1)
Now, if we called delete in either of those objects the object would be removed from the DB along with the relation between both objects. Up until this point I understand.
But is there any way of doing that, if an Article is removed, then, all the Publications that are not related to any Article will be deleted from the DB too? Or the only way to achieve that is to query first all the Articles and then iterate through them like:
to_delete = []
qset = a1.publications.all()
for publication in qset:
if publication.article_set.count() == 1:
to_delete(publication.id)
a1.delete()
Publications.filter(id__in=to_delete).delete()
But this has lots of problems, specially a concurrency one, since it might be that a publication gets used by another article between the call to .count() and publication.delete().
Is there any way of doing this automatically, like doing a "conditional" on_delete=models.CASCADE when creating the model or something?
Thanks!
I tried with #Ersain answer:
a1.publications.annotate(article_count=Count('article_set')).filter(article_count=1).delete()
Couldn't make it work. First of all, I couldn't find the article_set variable in the relationship.
django.core.exceptions.FieldError: Cannot resolve keyword 'article_set' into field. Choices are: article, id, title
And then, running the count filter on the QuerySet after filtering by article returned ALL the tags from the article, instead of just the ones with article_count=1. So finally this is the code that I managed to make it work with:
Publication.objects.annotate(article_count=Count('article')).filter(article_count=1).filter(article=a1).delete()
Definetly I'm not an expert, not sure if this is the best approach nor if it is really time expensive, so I'm open to suggestions. But as of now it's the only solution I found to perform this operation atomically.
You can remove the related objects using this query:
a1.publications.annotate(article_count=Count('article_set')).filter(article_count=1).delete()
annotate creates a temporary field for the queryset (alias field) which aggregates a number of related Article objects for each instance in the queryset of Publication objects, using Count function. Count is a built-in aggregation function in any SQL, which returns the number of rows from a query (a number of related instances in this case). Then, we filter out those results where article_count equals 1 and remove them.
Whenever we save data to the database, there is always a corresponding ID which we use to fetch the data from that specific column.
sql_con.execute("SELECT FROM DBNAME WHERE ID = ?", id)
The above code only allows us to fetch data based from the ID. The problem is that the above code only accepts 1 supplied binding. In my database, I used sets of strings as the ID for each column, which means that the binding of my IDs are more than 1. And, those sets of strings have different bindings (or character count).
How do I modify the code in above, so I could input strings as my ID, preventing it from receiving the specific error:
sqlite3.ProgrammingError: Incorrect number of bindings supplied. The current statement uses 1, and there are 8 supplied.
Thank you in advance. I use Python 3.xx and in-built module sqlite3. Database is in .db file format and is a disk-based database.
I found the answer for my own question, by asking someone else.
For you to resolve this problem with the bindings of the input, just simply convert the parameter into a tuple.
OLD CODE:
sql_con.execute("SELECT FROM DBNAME WHERE ID = ?", id)
INTO THIS...
NEW CODE:
sql_con.execute("SELECT * FROM DBNAME WHERE ID = ?", (id,))
Hope it helps.
i am trying to filter records using key.For example
localhost:5984/school/_design/school/_view/schoolstats?startkey=[Name,DOB,AGE]&endkey=[Name,DOB,AGE]
1)filter using Name only
2)filter using Name and Age only
3)filter using Name and DOB only
4)filter using Age only
I have tried a lot using wildcard in couchdb but cant able to fetch the exact result.
If you use a ranged query with startkey and endkey, the order of keys is not changeable.
These combination should be working. If you need other combination you have to emit your multikey in the desired form.
startkey=[Name]&endkey=[Name,{}]
startkey=[Name,DOB]&endkey=[Name,{}]
startkey=[Name,DOB,AGE]&endkey=[Name,{}]
startkey=[Name,DOB]&endkey=[Name,DOB,{}]
For your asked filters, you have to emit two more keys/multikeys in your map function.
I think, if you do not change your emitting keys, aka, you have a emitting statement like: emit [Name,DOB,AGE], null
1)Filter using Name only
startkey=[Name]&endkey=[Name,{}]
2)Filter using Name and Age only
Can not
3)Filter using Name and DOB only
startkey=[Name,DOB]&endkey=[Name,DOB,{}]
4)Filter using Age only
Can not
I have been exclusively using cypher queries of this client for Neo4j because there is no out of the box way of doing many things. One of those id to get nodes. There is no way to retrieve them without knowing their id, which is very low level. Any idea on how to run a
$client->findOne('property','value');
?
It should be straightforward but it isn't from the documentation.
Make Indexes on the properties you want to search, from a newly created $personNode
$personIndex = new \Everyman\Neo4j\NodeIndex($client, 'person');
$personIndex->add($personNode, 'name', $personNode->name);
Then later to search, the new PHP object $personIndex will reference the same, populated index as above.
$personIndex = new \Everyman\Neo4j\NodeIndex($client, 'person');
$match = $personIndex->findOne('name', 'edoceo');
As the question suggests, I need to find out how to access entity data that has been passed into a JavaScript function via a lookup.
JavaScript Code Follows:
// function to generate the correct Weighting Value when these parameters change
function TypeAffectedOrRegionAffected_OnChanged(ExecutionContext, Type, Region, Weighting, Potential) {
var type = Xrm.Page.data.entity.attributes.get(Type).getValue();
var region = Xrm.Page.data.entity.attributes.get(Region).getValue();
// if we have values for both fields
if (type != null && region != null) {
// create the weighting variable
var weighting = type[0].name.substring(4) + "-" + region;
// recreate the Weighting Value
Xrm.Page.data.entity.attributes.get(Weighting).setValue(weighting);
}
}
As you can see with the following line using the name operator I can access my Type entity's Type field.
// create the weighting variable
var weighting = type[0].name.substring(4) + "-" + region;
I am looking for a way now to access the values stored inside my type object. It has the following fields new_type, new_description, new_value and new_kind.
I guess I'm looking for something like this:
// use value of entity to assign to our form field
Xrm.Page.data.entity.attributes.get(Potential).setValue(type[0].getAttribute("new_value"));
Thanks in advance for any help.
Regards,
Comic
REST OData calls are definitely the way to go in this case. You already have the id, and you just need to retrieve some additional values. Here is a sample to get you started. The hardest part with working with Odata IMHO is creating the Request Url's. There are a couple tools, that you can find on codeplex, but my favorite, is actually to use LinqPad. Just connect to your Org Odata URL, and it'll retrieve all of your entities and allow you to write a LINQ statement that will generate the URL for you, which you can test right in the browser.
For your instance, it'll look something like this (it is case sensitive, so double check that if it doesn't work):
"OdataRestURL/TypeSet(guid'" + type[0].Id.replace(/{/gi, "").replace(/}/gi, "") + "'select=new_type,new_description,new_value,new_kind"
Replace OdataRestURL with whatever your odata rest endpoint is, and you should be all set.
Yes Guido Preite is right. You need to retrieve the entity by the id which come form the lookup by Rest Sync or Async. And then get Json object. However for make the object light which is returned, you can mention which fields to be backed as part of the Json. Now you can access those fields which you want.