Is it possible to hide columns by index? The hideColumn() function uses the field NAME:
hideColumn(columnField)
I guess I'll have to create an array of fieldnames and do it that way?
You can take the name of the data field in a certain column, specifying its index like this:
$("#grid .sui-gridheader th.sui-headercell:eq(0)").attr("data-field")
However, you will have to take into account things such as whether it is hidden or not.
Related
I usually use jsonb field store array data.
for example, I want to store customer's barcode info, I will create a table like this:
create table customers(fcustomerid bigint, fcodes jsonb);
One customer has one row, all barcode info stored in its fcodes field, just like below:
[
{
"barcode":"000000001",
"codeid":1,
"product":"Coca Cola",
"createdate":"2021-01-19",
"lottorry":true,
"lottdate":"2021-01-20",
"bonus":50
},
{
"barcode":"000000002",
"codeid":2,
"product":"Coca Cola",
"createdate":"2021-01-19",
"lottorry":false,
"lottdate":"",
"bonus":0
}
...
{
"barcode":"000500000",
"codeid":500000,
"product":"Pepsi Cola",
"createdate":"2021-01-19",
"lottorry":false,
"lottdate":"",
"bonus":0
}
]
The jsonb array maybe store millions of barcode's objects with the same structure. Perhaps this is not a good idea, but you konw when I have thousands of customer, I can store all the data in one table, one customer has one row in this table, all its data store in one field, it looks very tersely and easy to manage.
For this kind of application scenarios, how to efficiently to insert or modify or query the data?
I can use jsonb_insert to insert one object, just like:
update customers
set fcodes=jsonb_insert(fcodes,'{-1}','{...}'::jsonb)
where fcustomerid=999;
When I want modify some object, I found it is a little difficulty, I should know the index of object first, if I use the incremental key codeid as the array index, things looks easilly. I can use jsonb_modify,Just like below:
update customers
set fcodes=jsonb_set(fcodes,concat('{',(mycodeid-1)::text,',lottery}'),'true'::jsonb)
where fcustomerid=999;
But if I want to query the objects in the jsonb array with createdate or bonus or lottorry or product, I should use jsonpath operator. just like:
select jsonb_path_query_array(fcodes,'$ ? (product=="Pepsi Cola")'
from customer
where fcustomerid=999;
or like:
select jsonb_path_query_array(fcodes,'$ ? (lottdate.datetime()>="2021-01-01".datetime() && lottdate.datetime()<="2021-01-31".datetime())'
from customer
where fcustomerid=999;
Thie jsonb index looks useful, But it looks useful between different row, and my operation mostly works in one row's one jsonb field.
I am very worrying about the efficiency, for millions of objects stored in one row's one jsonb field, is this a good idea? And how to improve the efficiency in this scenarios? Especially for the query.
You are right to worry. With a huge JSON like that, you will never get good performance.
Your data don't need JSON at all. Create a table that stores a single barcode and has a foreign key reference to customers. Then everything will be simple and efficient.
Using JSON in the database is almost always the wrong choice, judging from the questions in this forum.
I have a table connected to AppSheet that has a column called "Names" there are many values that have the same name with different information. Is there anyway in AppSheet to have the user tap on one name and have all of the values show up that have the same Customer name. Essentially grouping.
I know there is a community on Google Plus for AppSheet but it doesn't seem very active my question has been sitting on the site for weeks. If anyone needs more clarification please ask.
Not very clear what you are trying to achieve, but you can correct me if I'm wrong.
You want in the Inline view of any given Customer, to have a list of referenced values.
You can do this with a SELECT() function. In Data > Columns > + "Virtual column"
In the "App formula" input add your function.
For example: SELECT( myTable[myColumn], [Name] = [_THISROW].[Name])
What this does:
List all values from column named "myColumn" in table "myTable"
where "Name" has the same "Name" as this row,
https://help.appsheet.com/expressions/functions/select
If you want to list not only values but a list of referenced rows from another table, you should use REF_ROWS.
For example REF_ROWS("myOrdersTable", "orderCustomer")
What this does: list all rows from table named "myOrdersTable" where column named "orderCustomer" has the same value as the unique KEY of this row.
REF_ROW virtual columns are generated automatically when you give a "REF" type to any column. In this example if you go to Data > Columns > "myOrdersTable" and change the type of "orderCustomer" to "REF" with "ReferencedTableName" to "myCustumerTable", a virtual column with list of referenced rows will be generated in "myCustumerTable" table after you save.
https://help.appsheet.com/data/references/references-between-tables
I'm using postgresql database which allows having an array datatype, in addition django provides PostgreSQL specific model fields for that.
My question is how can I filter objects based on the last element of the array?
class Example(models.Model):
tags = ArrayField(models.CharField(...))
example = Example.objects.create(tags=['tag1', 'tag2', 'tag3']
example_tag3 = Example.objects.filter(tags__2='tag3')
I want to filter but don't know what is the size of the tags. Is there any dynamic filtering something like:
example_tag3 = Example.objects.filter(tags__last='tag3')
I don't think there is a way to do that without "killing the performance" other than using raw SQL (see this). But you should avoid doing things like this, from the doc:
Tip: Arrays are not sets; searching for specific array elements can be
a sign of database misdesign. Consider using a separate table with a
row for each item that would be an array element. This will be easier
to search, and is likely to scale better for a large number of
elements.
Adding to the above answer and comment, if changing the table structure isn't an option, you may filter your query based on the first element in an array by using field__0:
example_tag3 = Example.objects.filter(tags__0='tag1')
However, I don't see a way to access the last element directly in the documentation.
I have 2 column in my table setting
with the following values
KEY VALUE
company ABC
phone 14344
address Somerset City
I need to display this like a single record or a flatten
array in the view/blade page
something like
{{$sett->company}}
{{$sett->phone}}
or an array with lookup
{{$myarray('company')}}
{{$myarray('phone')}}
The idea is if I add another settings like contact us email address
for my website I don't want to add another column.
I know this is achievable in controller by creating different variable
and executing different query but I'm kind of looking for some options here.
Thanks for the help really appreciated.
You can use $settings->pluck('value', 'key') to get your result. Read more here: https://laravel.com/docs/5.4/collections#method-pluck
I have a listing site having a model with many properties on which I would like to use filters. I would like to use memcache and cursor for querying, e.g:
results=Model.all().filter("x =", a).filter("y =",b).with_cursor(cursor).fetch(20).
How should I handle cursor and pagination, when the user change the filter criteria, e.g.
from `x=a to x=c`?
Should I store cursor having key = query string? But then the query string changes with page numbers :( . I guess i will need to parse query string, remove page numbers and use that as a key for cursor. Is that how I should do it?
You can make an "hash" of your current filter, and pass it to view. That can be stores there as an hidden field, like <input type="hidden" name="prev_query" value="{{query_hash}}"/>
On second request you'll check that current filter's hash equals to passed as parameter.
'Hash' maybe md5 of your filter params, or just join concatenation of them.
Think of a cursor like a bookmark, holding place in a result set. Cursors are specific to the query they are for. You can't use the same cursor for two different queries - that would be akin to expecting a bookmark from one book to show you how far through you are in another.
If you want to store cursors elsewhere, you'll need to key them by the filter criteria so you can look up the appropriate one. Memcache is a poor choice, though, as elements may be evicted at any time. Why not just make the cursor part of the 'next page' URL?