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Questions tagged [data-retrieval]

Data retrieval involves extracting the wanted data from a dataset.

In order to retrieve the desired data the user present a set of criteria by a query which selects the demanded data from the dataset. The retrieved data may be stored in a file, printed, or viewed on the screen.

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What information can we access from the client?

I'm trying to compile a list of information that is accessible via javascript such as: Geo-location IP address Browser software Exit location Entrance location I understand that a user can alter any of this information and that it's reliability is…
George Reith
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How do I link each user to their data in Firebase?

I plan to create a main tree named users which will include the name different users used as username. So, from each username will be included their data e.g. Full Name, Address, Phone No. I want to know how to get each user's data when they log in…
Oladipo
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view config getter callback for component 'div' must be a function (received 'undefined'). Make sure to start component names with a capital letter

Error is: Invariant Violation: view config getter callback for component 'div' must be a function (received 'undefined'). Make sure to start component names with a capital letter. I am getting this error while trying to retrieve data from firebase…
developer_user
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Saving data upon closing app and retrieving that data

I know, there are plenty of questions in regards to saving/retrieving data on here. I was doing find looking things up on my own and really thought I could manage to find my answers without having to "ask a question", but I began to wonder…
lilgodwin
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How to evaluate a search/retrieval engine using trec_eval?

Is there any body who has used TREC_EVAL? I need a "Trec_EVAL for dummies". I'm trying to evaluate a few search engines to compare parameters like Recall-Precision, ranking quality, etc for my thesis work. I can not find how to use TREC_EVAL to…
Babak
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How do I calculate TF-IDF of a query?

How do I calculate tf-idf for a query? I understand how to calculate tf-idf for a set of documents with following definitions: tf = occurances in document/ total words in document idf = log(#documents / #documents where term occurs But I don't…
Codarus
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What is the point of salt and hashing if database is accessible?

I just learned the concept of hashing ("Hey! don't forget the salt!") and using salt to make the password secured. Hashing it is a one way encryption (actually not encryption but hashing) so it cannot be reversed engineered. Salting is prefixing or…
kazinix
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How to avoid many database round trips and a lot of irrelevant data?

I have worked with various applications and encountered this situation many times. Until now I have not figured out what is the best approach. Here's the scenario: I have an application either desktop or web I need to retrieve simple documents from…
kazinix
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idf has no effect on ranking one term queries

I was reading through this article and it said that Note that IDF is dependent on the query term (T) and the database as a whole. In particular, it does not vary from document to document. Therefore, IDF will have no effect on 1-word…
Bill Cheng
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Extracting jpegs from a disk dump

I've got a 16GB memory card off someone that won't load properly (asks to be reformatted). I'm trying to get jpegs off it. I've run dd to dump the contents to a file, which worked splendidly. The file won't mount and be read, so the contents are…
Rich Bradshaw
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LINQ to SQL Storing query results in a variable

For example I am searching for a specific persons ID and I want to store that ID to a local variable or instance variable. How do I retrieve Query results and stores them in a int Variable with LINQ to SQL? Assuming we have this query from user in…
user962206
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Get data from android notification

I am trying to extract some data from an android notification. When I receive a mail, I can get the name of the sender from the title attribute and the rest of the notification is in the text attribute with the following code: @Override public void…
Thomas P.
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How to retrieve all the entries with hash key as a particular pattern in dynamo DB?

I am new to amazon web services. I want to retrieve all the entries in the dynamo DB table which have a particular word in their hash key. It is similar to using like operator in oracle DB. How can I do it? If its not possible, how do I retrieve all…
coder
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Get data of a document in firestore by giving a field value belonged to that document using Python?

I'm new to python. I'm using a firebase firestore database for this project. After entering the Admission_No, I want to retrieve all the data in the relevant document such as name, grade, phone. I tried to write a program for it. But I failed.…
I'm a Studnet
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How to retrieve float from Firestore?

Hi I have problem with retrieving data from Firestore. I don't know how to retrieve data from number field with dot. For example Prize : 2.54 I tried this longPrize = documentSnapshot.getLong("Prize"); but it don't work because it's returns only…
Adam Jefer
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