I would like to have a gridpanel with columns that are broken into 2 sub-columns, kind of like this:
| Monday | Tuesday | Wednesday | Thursday |
| In | Out | In | Out | In | Out | In | Out |
| 9 | 4 | 10 | 5 | 8:30| 4 | 10 | 5 |
Is this possible with ExtJS?
Yes, this is definitively possible. However, you will not find this as out-of-the-box functionality. There is a user extension/plugin (2.0 here) that should do the trick for you. There is also an example in the ExtGWT samples demo that has similar functionality.
In Ext 4.1.3 You can see http://docs.sencha.com/ext-js/4-1/#!/example/grid/group-header-grid.html
It supports group headers.
Related
I wish to use Datastore, but I read that an entity size is limited to 1mb.
I have an entity "Users", which contains around 50k "User". I wonder if the entity size restriction is not too restrictive for my case. And if a day I will have more users, will I be blocked.
This is how I imagine my database, maybe I misunderstood how it's supposed to work:
+--------- Datastore -------------+
| |
| +---------- Users ------------+ |
| | | |
| | +---------- User ---------+ | |
| | | Name: Alpha | | |
| | +-------------------------+ | |
| | | |
| | +---------- User ---------+ | |
| | | Name: Beta | | |
| | +-------------------------+ | |
| +-----------------------------+ |
+---------------------------------+
Where "Users" is an entity which contains entities "User".
Thank you.
Your "KIND" is user, your "entities" are EACH user. So no matter how MANY users you have, as long as EACH user is under a meg, you're fine.
The only limit to the size of the full "kind" is what you're willing to pay in storage. Reading up on this doc, or watching this introduction video could give some high level advice to your situation.
To better understand keys and indexes (another VERY important concept of datastore), I would suggest this video that explains VERY well how composite indexes work and behave :)
I would like to check whether
if there any ways to delete the record in the page, without deleting records in database?
I'm doing a shopping cart and would like to have the user to be able to view back their past transaction.
Is there any ways that I could delete the records in the cart, after I check out? And also able to view the past transaction.
I've not done any code yet,
just seeking for advices
Yes. You can have a database with the products, a second with your users and a third one to associate the users id with the products id they purchased.
You can never delete a item from the database. You can include a information of status like 'active/inactive' instead of actually deleting it.
Edit
When you have products in cart, usually the list is saved in cookies, temporarily by browser or javascript or another way (if your country forbid cookie, you have to search for alternatives). Once the purchase is finished, the cart list is saved in database and the cookie or whatever is cleared. You do not delete anything from database.
Example
Users/ buyers database
+--------+----------+
| idUser | nameUser |
+--------+----------+
| 1 | Antony |
| 2 | Betty |
| 3 | Carl |
+--------+----------+
Products database
+-----------+--------------+-------+-----------+
| idProduct | nameProduct | price | available |
+-----------+--------------+-------+-----------+
| 1 | Apple dozen | 10.00 | yes |
| 2 | Banana unity | 20.00 | yes |
| 3 | Cherry kg | 30.00 | yes |
+-----------+--------------+-------+-----------+
Active/ Inactive Example
Notice here how you don't need to delete any record ever. You can create a option such like available to products like example above. So you can just set it to yes or no. So you just code your front-end to show products which available is yes while your back-end can see all of them. It is very useful. In a case when your product has tens of information and you delete the product, but it will only be unavailable for 3 weeks, you would lose a great time deleting and typing and saving everything again. It is much better just set it to show or not to show. (Some stores just opt to show everything, but alert when it is unavailable).
Have in mind that it isn't a rule for everything. Always look for the best perfomance. If you have a database with 10k unavaiable products that will never be available again and you just have 2 available itens, it would be a little nosense keep all this records alive.
About prices historic
Prices Historic Database
+--------+--------+-----------+-----+----------+----------+
| idItem | idUser | idProduct | qty | subtotal | date |
+--------+--------+-----------+-----+----------+----------+
| 1 | 1 | 1 | 2 | 20 | 10/10/13 |
| 2 | 1 | 2 | 1 | 20 | 10/10/13 |
| 3 | 2 | 1 | 1 | 10 | 11/12/13 |
| 4 | 2 | 2 | 1 | 20 | 11/12/13 |
| 5 | 2 | 3 | 1 | 30 | 11/12/13 |
| 6 | 1 | 1 | 1 | 10 | 01/06/14 |
+--------+--------+-----------+-----+----------+----------+
It is always good to have a unique identification for each row on database. Well, in most cases. Its is not very readable for humans, but it fits well for machines. Check this database. The line 1 and 2 say us that user 1 bought on 10/10/13 the item with id 1 x 2 and item with id 2 x 1. Translating: Antony bought 2 Apple dozen and 1 Banana unity.
In this database you could filter rows by user and them group by Date. You would see that Antony bought more Apples in 01/06/2014.
I personally like to save the subtotal on database. If in 2015 the apple price raise to 15.00, you and the user can see he paid 10.00 in 2013 and you can do reverse calc to get the individual price.
If you could read this thid database well, you see Betty bought one of each item in 11/12/13 and Carl has never bought anything.
I believe and hope it will help you.
It is just a simplified example on how the logic works. I matched the product directly with buyer, but most stores usually add a 4th database just to list Orders. So you relate Users with Orders and Orders with Products. Everything has its advantages and disadvantages
There is a database of spare parts for cars, and online search by the name of spare parts. The user can type in the search, for example "safety cushion" or "airbag" - and the search result should be the same.
Therefore, I need somehow to implement the aliases for names of spare parts, and the question is how to store them in the database? Until now I have only one option that comes in mind - to create an additional table
| id | name of part | alias_id |
-------------------------------------------------- ---------------
| 1 | airbag | 10 |
| 2 | safety cushion | 10 |
And add additional field "alias_id" to table containing all the spare parts, and search by this field...
Are there other better options?
If I have understood correctly, it's best to have 3 tables in a many to many situation (if multiple parts have multiple aliases:
Table - Parts
| id | name of part |
-----------------------
| 1 | airbag |
| 2 | safety cushion |
Table - Aliases
| id | name of alias |
-----------------------
| 10 | AliasName |
Table - PartToAliases
| id | PartId | AliasId |
-------------------------
| 1 | 1 | 10 |
| 2 | 2 | 10 |
Your solution looks fine for the exact problem you described.
BUT what if someone writes safetycushion? or safety cuschion? With these kinds of variations your alias lookup table will soon become huge and and manualy maintaining these will not be feasible.
At that point you'll need a completely different approach (think full text search engine).
So if you are still sure you only need a couple of aliases your approach seems to be fine.
I met some problems with creating table using Extjs. My table has difficult structure
-------------------------------------------|
| | | 4 |
| | 2 ---------|
| | | 5 |
| 1 |---------------------------|
| | | 6 |
| | 3 ---------|
| | | 7 |
-------------------------------------------|
The data from the server are as following:
1 2 4
1 2 5
1 3 6
1 3 7
Every sequence is an array
I need them to be grouped as at the picture above.
Any ideas?
You can use PivotGrid. Example: http://dev.sencha.com/deploy/ext-3.4.0/examples/pivotgrid/simple.html
Unfortunately it is only available in Ext JS 3. It should be available in Ext JS 4.1 though.
It looks like you need to group on the first two columns but unfortunately Ext.data.Store only supports one level of grouping. You'll have to extend Store to support more and Ext.grid.feature.Grouping to take advantage of it.
Is there any Extjs component to represent an editable matrix.
Something along these lines:
+------------------------------------+
| name | bid1 | bid2 | bid3 |
+------------------------------------+
| supplier A | |
| supplier B | |
| supplier c | |
+------------------------------------+
Like an editable grid? Have you looked at all of the grid samples?
You are looking for a pivot table. Options:
https://market.sencha.com/extensions/mzpivotgrid
or for extjs 3.4† :
http://docs.sencha.com/extjs/3.4.0/#!/api/Ext.grid.PivotGrid
† (you can use 3 and 4 at the same time with the compatibility layer) http://www.sencha.com/blog/ext-js-3-to-4-migration/
Refer here. You can edit any entry in grid using editable grid panel.