Updating table content using SQLite? - iphone

Friends, here is my problem: I populate a table in Xcode using SQLite database. Here is what I want - If my table has 20 rows and all of them are populated, how to update the table if new data is saved in my SQLite database? I want the new information to overwrite the old one. How to do that in Xcode, any ideas? Thanks in advance! I am not sure if the info that I provided is enough, so let me know if you want some code or other stuff.

The key to what you're doing is in the routine you furnish for your table: cellForRowAtIndexPath. Basically, you can write that routine to furnish whatever data you want it to furnish. Once you know that your data has been updated, you can cause the entire table to refresh with a call to reloadData.

Related

save new and edited table values into core data

i searching for the best way to realize the following situation:
i have data in my core data.
i open the view controller with my tableview
this tableview fetchts the core data values
but now the questions:
how should i solve the situations for new values and edited values:
Situation 1:
i can add a row with a button and fill it with data
Should i directly save it into core data, each time if a row is added?
Situation 2:
if i edited an exist row, should i directly update the exist record?
At the moment:
I request the records and save them into an array.
and all new changes will be apply to the array.
if the view will disappear, i delete all the requested records in core data and save the array value into core data. is this a good way? i think not ...

Inserting data properly in to sqlite database

I am developing an app that contains a view controller,where the user fills all the fields and when he clicks save,the data must get inserted in to the database.I am able to retrieve the primary key (id) for every reminder saved.But I am unable to insert data,as when I am trying to display it in console,it's displaying null.Please post the correct and relevant code of my requirement to save the data in to created table in database.
It's my humble request to post the code for performing an action in such a way that when I click save,the data must get inserted in to the table of database.I would be pretty glad If I can see the code for retrieval of data to display in the other controller(page) "View/Edit Reminder"...Please help me out.I tried all the ways,I have gone through 100's of solutions.
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Why does SQLite not bring back any results from my database
http://www.edumobile.org/iphone/iphone-programming-tutorials/adding-data-using-sqlite-for-iphone/
etc... etc... Please make me get out of this problem
Check the answer of this question:
Storing and retrieving data from sqlite database
It shows how to connect to a database, insert a new record, and retrieve an old one.
Check Out this link:-
how to insert only one username and password in sqlite database
I have explain two method first is how to read from a table and second how to write inside the database.Just before calling any of these methods you have to call the method checkandCreateDatabase.

Does Sqlite on the Iphone reorder database rows when I delete a row?

I'm quite new to iphone programming. I would like some information with you. Here is the structure of my database:
ID_song : auto-int (primary key)
txt_song : text
When we do delete some data from a table view, and when the data is deleted from the SQLite database, let's say I have only 3 songs in my database
id_song:1 txt_song:Song_A
id_song:2 txt_song:Song_B <------ (To be deleted)
id_song:3 txt_song:Song_C
After deleting the rows, does the data in the table looks like:
id_song:1 txt_song:Song_A
id_song:3 txt_song:Song_C
or
id_song:1 txt_song:Song_A
id_song:2 txt_song:Song_C
I mean, does sqlite reorganise the index?
Why would it do that ?
First of all, that could make a huge performance hit and a real risk to violate the integrity of the data.
Changing the primary key, means that all related foreign keys have to be changed as well.
No, it does not. (which you probably could've figured out in about 5 minutes by trying it yourself. :))
No. No Database will rewrite an ID field after deletion of a row. If you wish to number your songs, you will need to do this yourself in code.
it looks like
id_song:1 txt_song:Song_A
id_song:3 txt_song:Song_C

iPhone:How do i insert few rows in the middle of existing table?

If i want to insert few rows in the middle of the existing table, how do i approach it? Where all that i should be careful when doing such thing? Is there any good sample source available?
Appreciate your helps.
Thank you.
Tableviews don't contain data and they don't actually contain rows themselves. Instead, tableviews are just an illusion created by redisplaying the same tableviewcell objects over and over again with different data each time. The real table, the real rows, are actually in the logical data.
So, to " insert few rows in the middle of the existing table" you actually add the rows into the data that the table displays. For example, if you had a simple array of names that you display in the table, you would insert the new names into the array. Then you would call -[UITableView reload] which will cause the table to ask the datasource for the new data.
See the Table View Programing Guide for iPhone OS.
Insert the data into your model and call reloadData on the table. If you need to animate the insertion for some reason, you can use insertRowsAtIndexPaths:withRowAnimation:, but the principle if updating the model first still applies.

Regarding ADO.Net

I have fetched some 1000 records using data adaptor and displayed in the UI(DataGrid).
Now whenever user is changing the value in anyone of the row in the data grid, that
particular value has to be updated into database table. Currently i am dumping the entire
table again using adaptor.update. i dont want to do that...i just want to update only that
row..how can i achieve this .?? can anybody help regarding this ?
You can get and pass to adapter only changed rows by calling DataSet.GetChanges() or DataTable.GetChanges methods