I have a model called DemoModel and contains 1000 records in DB. So i am paginating using paginator in Django(assume that per page 15 records, so i have 67 pages).
So i want to get the records of 3,4 and 5 pages and i have to append the records into list.
So can i get the objects_list based on page range or anything else i want to do?
Example:
records.page(1)
Here i am getting only one page records at a time, but how can i get multiple page records i.e; from fist page to third page
Assuming you are asking about the API request to get the paginated resources, and you are using the default pagination class: rest_framework.pagination.LimitOffsetPagination, then you can make an request as such:
https://api.example.org/accounts/?limit=30&offset=15
which in turns give you the 2nd and 3rd "page".
The limit indicates the maximum number of items to return, and is equivalent to the page_size in other styles. The offset indicates the starting position of the query in relation to the complete set of unpaginated items. doc link
Related
I have 100 rows of data in DynamoDB and a api with path api/get/{number}
Now when I say number=1 api should return me first 10 values. when I say number=2 it should return next 10 values. I did something like this with query, lastEvaluatedKey and sort by on createdOn . Now the use case is if the user passes number=10 after number=2 the lastEvaluatedKey is still that of page 2 and the result would be data of page 3. How can I get data directly. Also if the user goes from number=3 to number=1 still the data will not be of page 1.
I am using this to make API call based of pagination on HTML.
I am using java 1.8 and aws-java-sdk-dynamodb.
Non-sequential pagination in DynamoDB is tough - you have to design your data model around it, if it's an operation that needs to be efficient at all times. For a recommendation in your specific case I'd need more details about the data and access patterns.
In general you have the option of setting the ExclusiveStartKey attribute in the query call, which is similar to an offset in relational databases, but only similar and not identical. The ExclusiveStartKey is the key after which the query will continue, meaning data from your table and not just a number.
That means you usually can't guess it, unless it's a sequential number - which isn't ideal.
For sequential pagination, i.e. the user goes from page 1 to page 2, page 2 to page 3 etc. you can pass that along in the request as a token, but that won't work if the user moves in the other direction page 3 to page 2 or just randomly navigates to page 14.
In your case you only have a limited amount of data - 100 items, so my solution for your specific case would be to query all items and limit the amount of items in the response to n * 10, where n is the result page. Then you return the last 10 items from that result to your client.
This is a solution that would get expensive at scale (time + cost) though, fortunately not many people will use the pagination to go to page 7 or 8 though (you could bury a body on page 2 of the google search results).
Yan Cui has written an interesting post on this problem on Hackernoon, you might want to check it out.
I have few filters on the view page and want to show the count that matches the given conditions. Like on the product search result I have Free Shipping filter. I need the count of records matching my filters in the total record not just in the current page.
Explanation:
Suppose In the result set I have 100 records with pagination 20/page, 40 of them has free_shipping = 1. I want to show like Free Shipping(40). Currently, I do $products->where('free_shipping', 1)->count() but this gives me the result matching only in viewed records.
How can I get the total number of matching records regardless of pagination?
Thanks in advance
if Laravel Pagination is used then you can use the total() method.
Example :
$products->total();
I have a requirement where I need to display a long table. It doesn't have to be displayed all at once, so ajax loading it is (load first 50 recs, then get another 50 rows everytime the user scrolls to/past the tenth row from the last).
But I'm not sure which of the two, pagination and infinite scrolling, is better. I'd like the user to be able to skip to the last scrolled-to point when returning to the page (through Back button, definitely; if I can do that whenever, however user visits the page, even better!) with the previous rows visible as well. At the same time, for performance, I want to restrict the number of ajax calls to as low as I can keep it.
Any thoughts?
To implement such scenerio, first consume an api with page no and number of records as request params in API calls
For Ex- 'www.abc.com/v1/tableData/pageId=1&noOfRecords=50'
Then you will get the first 50 records. Its response should also provide you the total number of recors avaiallbe in database after callling first api .
When you scroll down, increase the pageId with +1
For ex - 'www.abc.com/v1/tableData/pageId=2&noOfRecords=50'
In the same way, you will increase the pageId untill you check the total records you got till now, should be equals to the total records, you are getting from API key.
In this way you can able to impmentent it.
Talking about performance, its up to you whther you are using pagination or scroll, it does not matter, since you are restricting the number of records to display.
Need some advice and help from you!
Two questions.
how can I retrieve a list of patient resources with 30 _counts and sorted by last modified date? I don't have any searching parameters such as identifier, family and given;
since my application in browser is a single page application, when the user scroll down and all the first 30 patients have been shown, I will make another call to get the next 30 patients. I don't need the first 30 patients and just want the records from 31 to 60. What parameters should I used in this paging search? Do we have something like "?_count=30&_page=2". Similarly, if I need the page 100, I don't want the servers sending me the first 99 pages.
Thanks in advance.
Autorun
GET [baseUrl]/Patient?_count=30&sort=_lastUpdated
The response will be a Bundle. Look at the Bundle.link with a Bundle.link.relation of "next". The Bundle.link.url will be the URL to use to get the next "page" of content. The format of the URL is undefined and will be server-specific.
Be aware that _count only constrains the base resource. If you query Patient and do a _revinclude on Observation, you'll get 30 patients - but you'll also get all the observations for all 30 of those patients - which could be 10k+ rows in your result set - so be careful with _include and _revinclude.
I am using ASP/VB Script in my project but, i don't have much idea of Pagination in Classic ASP. I have designed a datagrid format using tables and looping. That table is filled by accessing database. As we have a huge amount of data to display, we need pagination.
Thanks in advance
The pagination problem is not inherently to ASP classic or VBScript. You need first to define which strategy to follow:
In the client:
Ajax style pagination (You can use a jQuery plugin like SlickGrid)
Linked pagination: Your page have links to page 1, page 2, etc.
Infite scrolling: This is a modern way to do pagination, with more results added to the page via ajax
In the server
Full DB results retrieve and return only the page asked. This is sometimes necessary.
Full DB retrieve but caching the result so subsequent page request come from the cache, not the DB
Ask the DB only the page asked (Different techniques depending on the DB engine)
There is a issue you need to be aware of... the built-in ASP record set will allow pagiing, however is not very efficient. The entire result set gets returned to the browser and then it locates the appropriate page and displays that data.
Think of it like this... your result set is a 4 shelf book case. When you ask for page one all 4 shelves of books get returned. The the display code says "Okay now only show page 1". If you then ask for page two... All four shelves of books gets returned and then the display code says "Okay give me page 4".
So, you should look for a paging solution that takes place on the server, inside the database. This way if you ask for page 15 of a 50 page result, the database will only return one shelf of books.
This google query should put you on the right track.
Edit: How SQL Paging Works
You must us a stored procedure
One of the input parameters is the page to view
The stored procedure filters the results on the server
Here is the basic concept of what happens inside the proc:
Step 1:
Create a temp table that stores the entire result set. My preference is to store only two values in this temp table. An identity seed value called RowId and the primary key of the result data. (I'm one of those people that believes in non-sensical identity seed keys)
Step 2:
Insert all the PKey values from the select statement into the temp table
Step 3:
Determine the StartRowId and EndRowId based on the input page parameter.
Step 4:
Select from the temp table using an inner join to the datatable on the PKey. In the where clause limit the result so the RowId (of the temp table) is between StartRowId and EndRowId. Make sure to Order By the RowId.
Set page size
recordset.PageSize = 100 ' number of records per page
Set the current page
recordset.AbsolutePage = nPage ' nPage being the page you want to jump to.
Other useful bits:
recordset.RecordCount ' number of records returned
recordset.PageCount ' number of pages based on PageSize and RecordCount
That's the basic info. You'll still need to loop through the appropriate number of records, and check the page number as it is passed back to the page.