I have a column and I would like to edit some of its rows. The problem is that the table is a view so I cannot edit the rows. How would I proceed to solve this problem?
SQLite doesn't let you update views. But it does allow triggers on views. So you can write an INSTEAD OF UPDATE trigger that makes the appropriate modifications to the underlying table.
As dan04 pointed out, you can use triggers to update views (like in most other databases). For sqlite, see http://www.sqlite.org/lang_createtrigger.html#instead_of_trigger
Example with a view called "myview", containing a table "my_t2"
CREATE TRIGGER myview_update INSTEAD OF UPDATE ON myview
BEGIN
UPDATE my_t2 SET field1 = new.field1, field2 = new.field2 WHERE my_t2.key = old.key;
END
If it's a view, it's not a table. The data for the view is drawn from one or more other tables. Edit the underlying table and when you examine the data in the view it will reflect the changes you made.
A SQL View is a virtual table, which is based on SQL SELECT query. Essentially a view is very close to a real database table (it has columns and rows just like a regular table), except for the fact that the real tables store data, while the views don’t. The view’s data is generated dynamically when the view is referenced. A view references one or more existing database tables or other views. In effect every view is a filter of the table data referenced in it and this filter can restrict both the columns and the rows of the referenced tables.
If you wish to modify the data in your table, you cannot do so with a view. SQL Views are always read-only. If you want to modify your table outside of the View, then use something like an UPDATE or ALTER TABLE statement.
Related
I have two tables Cashdisc and Convertterm, Does axapta have a functionality where Convertterm.code can be related to CashDisc.Code so that whenever converterm.code changes it can be updated in CashDisc.Code.
Yes. I think you're referring to a table relation.
If you want a table to update another table, you can do that through code, but I think you're talking about how the table naturally functions with table relations.
See here https://msdn.microsoft.com/en-us/library/bb190076(v=ax.10).aspx
You need to write custom code on Convertterm update method after super to update the Cashdisc table.
If you create table relation in child table and if you set validate property to yes, then you can restrict child data creation without a parent record.
I was wondering if there is any way to populate a table using two different records. My records have the same primary keys, but when I am adding the specific fields to my grid I have this error:
More than one data (key) in one scroll.
I tried to make a Control view field in my primary record, and then refer the new record fields as relative fields but in this case the data is not populating in my grid. Any help or hint will be much appreciated.
I've only done this where the 2nd record is a Derived/Work record.
Can you create a view that combines both records, and put the view in the grid? FYI, peoplesoft let's you update the data in a view, which is not typical in an oracle db system.
Ok guys finally after all discussion, and much try rounds I figured out how to do this.
You need to add a draw a grid beside your old grid and populate it with a new record, which has dynamic view (dynamic sql). The only important case there, is you need to make sure the order of your fields in your records, are in the same order of your fields in the SELECT statement of your sql. Otherwise you will see
an SQL error
.
Try to make a field as display control field which is acting as primary key for its native table and as Foreign key for some other record.. A field needs to be made related if is being fetched from some other record... that is from the record which is not under current consideration. I think this way one can fetch data into grid or scroll respectively from multiple records.
In my application i added all data into table view. Then I need entire row by using search operation.
Searching is based upon any data like search by RegisterNo or search by Name. By entering RegisterNo it Should display entire row related to RegisterNo.
To do search operation in a TableView, what I've done is to add a notion of filters.
For example if you want to filter by name, each time your name query change, you filter all your data and let on the table only those who match your query.
You always keep the full data to execute your query on it, but to display it use an other list.
with that I'm able to have lot of filters at the same moment and my view refresh in real time
I have a position class that i want to be able to write to the database. I currently have a entity for the class that is mapped to the database. I want to because to have the class insert data into one table and update entries in the other table. One table is for current positions and the other is for historical positions. Is it possible to map an entity to 2 tables and have it update 1 table and insert into the other?
Wouldn't it be easier to have a Trigger on the Update that Insert automatically a copy of the data in your history table?
Just don't do this. Use a database insert trigger.
I would make 2 different entities for this. If you want this to map to a single entity in your application you should write a data access class that (based on the data of your single entity) determines whether to do an update or an insert.
And I would personally never ever use a trigger for such a thing as this is business logic to me that needs to be exposed in the application so it can be tested.
I'm trying to image how can I delete a table row (core data or sqlite) using a Table View.
Well, I can do it with PHP using a hidden Id and then, looking for the matching Id in the data table to delete it.
In C# with the Entity Framework I can delete a table row with a simple DeleteObject instruction that will automatically remove it from the data table.
How can I do the same thing with iOS SDK? How can I tell the SDK to get the selected item id, find it in the data table and delete it?
Thank you,
Regards.
Use objectAtIndex:indexPath.row from within the didCommitEditingStyle method. This is assuming you have some sort of array that is being used to populate your TableView. This will return the object in your array that corresponds to the row that the user wishes to delete.