I would like to search my database for a value. I know you can do this for a key with db.search() but there does not seem to be any kind of similar function for searching for a value
I've tried using the contains() function but I have the same issue. It checks if the key is contained in the database. I would like to know if a certain value is contained in the database.
I would like to do something like this that would search for values in tinydb
db.search('value')
If I was able to execute the above command and get the value(if it does exist) or Nothing if it doesn't that would be ideal. Alternatively, if the able returned True or False accordingly, that would be fine as well
I don't know if this is what you are looking for but which the following command you can check for a specific field value:
from tinydb import Query
User = Query()
db.search(User.field_name == 'value')
I'm new here (doing some reading to see if TinyDB would even be applicable for my use case) so perhaps wrong, and also aware that this question is a little old. But I wonder if you can't address this by iterating over each field and searching within for your value. Then, you couldget the key or field wherein a value match was located.
Related
I have a dictionary that is being used to query the database for a match. I have one single query line that isn't working for me. If i have a list like this:
user['names']= [Alice, Bob, John]
Since this is a list I tried to use something like this:
q.filter(UserTable.firstname in user['firstnames'])
But for whatever reason this doesn't work. However, I know that Bob is in the database. When I manually pull down all the queries I can see the name is there in one of the rows. If I do this instead:
q.filter(UserTable.firstname == user['firstnames'][1]) #Only does Bob
It works. And when I pull all the queries manually, convert each row to a dictionary, and then do a
row[#row_that_matches].firstname in user['names']
that also works. But for some reason using the "in" keyword in sqlalchemy doesn't work as expected. Does anyone know an alternative that can make an sqlalchemy query for something in a list of values?
Use the in_() column method to test a column against a sequence:
q.filter(UserTable.firstname.in_(user['firstnames'])
See the Common Filter Operations section of the Object Relational tutorial:
IN:
query.filter(User.name.in_(['ed', 'wendy', 'jack']))
# works with query objects too:
query.filter(User.name.in_(
session.query(User.name).filter(User.name.like('%ed%'))
))
I have a mongodb collection that has documents that include both required and non-required data. I know how to create a query using the $exists operator to check if a field exists, however I do not want to define required field within the query, as the list is both long and subject to change (and is define elsewhere).
The following is great for checking a known field:
db.collectionofstuff.find({fieldIneed:{$exists:False}})
However I want something that function like this:
Using this Config file:
datadescriptorjson = {"thing1": {"count": 2,"range": 3},"thing2":{"pace": 12.5, "consistency": "angry"}}
create a query find/aggregation that looks something like this:
db.collectionofstuff.find({<list of fields from datadescriptorjson>:{$exists:Falze}})
I am not aware of anyway to do it directly with either the aggregation framework or using a simple find.
There is no such function, you will have to test each field manually. You can of course loop over your config data and recreate a query out of this. However, this should be something you do in your application.
Help! Can't figure this out! I'm getting a Integrity error on get_or_create even with a defaults parameter set.
Here's how the model looks stripped down.
class Example(models.Model):model
user = models.ForeignKey(User)
text = models.TextField()
def __unicode__(self):
return "Example"
I run this in Django:
def create_example_model(user, textJson):
defaults = {text: textJson.get("text", "undefined")}
model, created = models.Example.objects.get_or_create(
user=user,
id=textJson.get("id", None),
defaults=defaults)
if not created:
model.text = textJson.get("text", "undefined")
model.save()
return model
I'm getting an error on the get_or_create line:
IntegrityError: (1062, "Duplicate entry '3020' for key 'PRIMARY'")
It's live so I can't really tell what the input is.
Help? There's actually a defaults set, so it's not like, this problem where they do not have a defaults. Plus it doesn't have together-unique. Django : get_or_create Raises duplicate entry with together_unique
I'm using python 2.6, and mysql.
You shouldn't be setting the id for objects in general, you have to be careful when doing that.
Have you checked to see the value for 'id' that you are putting into the database?
If that doesn't fix your issue then it may be a database issue, for PostgreSQL there is a special sequence used to increment the ID's and sometimes this does not get incremented. Something like the following:
SELECT setval('tablename_id_seq', (SELECT MAX(id) + 1 FROM
tablename_id_seq));
get_or_create() will try to create a new object if it can't find one that is an exact match to the arguments you pass in.
So is what I'm assuming is happening is that a different user has made an object with the id of 3020. Since there is no object with the user/id combo you're requesting, it tries to make a new object with that combo, but fails because a different user has already created an item with the id of 3020.
Hopefully that makes sense. See what the following returns. Might give a little insight as to what has gone on.
models.Example.objects.get(id=3020)
You might need to make 3020 a string in the lookup. I'm assuming a string is coming back from your textJson.get() method.
One common but little documented cause for get_or_create() fails is corrupted database indexes.
Django depends on the assumption that there is only one record for given identifier, and this is in turn enforced using UNIQUE index on this particular field in the database. But indexes are constantly being rewritten and they may get corrupted e.g. when the database crashes unexpectedly. In such case the index may no longer return information about an existing record, another record with the same field is added, and as result you'll be hitting the IntegrityError each time you try to get or create this particular record.
The solution is, at least in PostgreSQL, to REINDEX this particular index, but you first need to get rid of the duplicate rows programmatically.
I'm having a database (sqlite) of members of an organisation (less then 200 people). Now I'm trying to write an wx app that will search the database and return some contact information in a wx.grid. The app will have 2 TextCtrls, one for the first name and one for the last name. What I want to do here is make it possible to only write one or a few letters in the textctrls and that will start to return result. So, if I search "John Smith" I write "Jo" in the first TextCtrl and that will return every single John (or any one else having a name starting with those letters). It will not have an "search"-button, instead it will start searching whenever I press a key.
One way to solve this would be to search the database with like " SELECT * FROM contactlistview WHERE forname LIKE 'Jo%' " But that seems like a bad idea (very database heavy to do that for every keystroke?). Instead i thought of use fetchall() on a query like this " SELECT * FROM contactlistview " and then, for every keystroke, search the list of tuples that the query have returned. And that is my problem: Searching a list is not that difficult but how can I search a list of tuples with wildcards?
selected = [t for t in all_data if t[1].startswith('Jo')]
but, measure, don't guess. I think that in some cases, the query would be faster - specially if you have too many records. Maybe you should use a query on the first char, and then start using python-side filter, since you already have the results.
I think that generally, you shouldn't be afraid of giving tasks to a database. It's quite possible that the LIKE clause will be very fast. Sqlite is implemented in fairly robust C code, and will happily deal with queries like this.
If you're worried about sending too many requests, why not send a query once a user has entered a threshold of characters, such as three?
A list comprehension is probably the best way to return the result if you want to do added filtering.
If you are searching for a string matching the start using LIKE, eg 'abc%' (rather than anywhere in the string - '%abc%'), the search should be quite fast if you have an index on the field, as the db can use the index to help find the matches.
I want to be able to check if a key_name for my model exists in the datastore.
My code goes:
t=MyModel.get_by_key_name(c)
if t==None:
#key_name does not exist
I don't need the object, so is there a way (which would be faster and cost less resource) to check if the object exist without returning it? I only know the key name, not the key.
You can't avoid get_by_key_name() or key-related equivalents to check if a key exists. Your code is fine.
The API talks about Model.all(keys_only=False) returning all the key names when keys_only is set to True
Look at the query that is fired for this, and then you can write a query similar to this but just for your object and see if any row is fetched or not.