Explain MVC through implementation of UITableView

Ans :

Read first about MVC

Let's understand to implement UITableview in MVC

1. We write fetching data query or request web-service and parse json,xml and save data to any global variable like dictionary, array, etc. So all inserting, fetching methods and data variable are comes under M.....Model

2. We make custom tableview cell, and put various types of views like UILabel, UITextField, UIButton for displaying in UITableView on screen. So this comes under V....View.

3. For displaying TableView, we will take UIVIewController or UITableviewController. This are responsible for various activity like telling how many section, rows are there, on delete button deleting row, how much height of cell, etc... So this comes under C....Controller.

Which delegate method called when I click on push notifications?

Ans : 
Different app delegate method called depends on following scenarios

For silent notification : 

App is in Foreground
No system alert shown
application:didReceiveRemoteNotification:fetchCompletionHandler: is called

App is in Background
System alert is shown
application:didReceiveRemoteNotification:fetchCompletionHandler: is called

App is in Suspended
App state changes to Background
System alert is shown
application:didReceiveRemoteNotification:fetchCompletionHandler: is called

App is Not Running because killed by user
System alert is shown
No callback is called

Normal Push Notification (no content-available) :

App is in Foreground
No system alert shown
application:didReceiveRemoteNotification:fetchCompletionHandler: is called

App is in Background or Suspended
System alert is shown
No method is called, but when user tap on the push and the app is opened
application:didReceiveRemoteNotification:fetchCompletionHandler: is called

App is in Not Running
System alert is shown
No method is called, but when user tap on the push and the app is opened
application:didFinishLaunchingWithOptions: then application:didReceiveRemoteNotification:fetchCompletionHandler: are both called

Add column in SQLite

Ans : 
If we have uploaded our app ver 1.0 and we want to add columns in sqlite database, then following thing can done.

If we have sqlite database which table structure can be changed after release. Then we need to maintain database version. We can update database version by excecuting query like PRAGMA user_version = version_num; (For swift : PRAGMA table_info(tblTest))

In second release If we need to add columns, then we can check database version, If database version is old version then we can execute following query :

ALTER TABLE {tableName} ADD COLUMN COLNew {type};

Query for last inserted row in SQL database

Ans. 

If column is primary key and integer, then ,

Sqlite : SELECT * FROM table ORDER BY column DESC LIMIT 1;

or

SELECT * FROM table WHERE ID = SELECT LAST_INSERT_ROWID()

FMDB : 

Last inserted id is : [fmdb lastInsertRowId];

Sqlite3 all functions : 

sqlite3_open: This function is used to create and open a database file. It accepts two parameters, where the first one is the database file name, and the second a handler to the database. If the file does not exist, then it creates it first and then it opens it, otherwise it just opens it.
sqlite3_prepare_v2: The purpose of this function is to get a SQL statement (a query) in string format, and convert it to an executable format recognisable by SQLite3.
sqlite3_step: This function actually executes a SQL statement (query) prepared with the previous function. It can be called just once for executable queries (insert, update, delete), or multiple times when retrieving data. It’s important to have in mind that it can’t be called prior to the sqlite3_preprare_v2 function.
sqlite3_column_count: This method’s name it makes it easy to understand what is about. It returns the total number of columns (fields) a contained in a table.
sqlite3_column_text: This method returns the contents of a column in text format, actually a C string (char *) value. It accepts two parameters: The first one is the query converted (compiled) to a SQLite statement, and the second one is the index of the column.
sqlite3_column_name: It returns the name of a column, and its parameters are the same to the previous function’s.
sqlite3_changes: It actually returns the number of the affected rows, after the execution of a query.
sqlite3_last_insert_rowid: It returns the last inserted row’s ID.
sqlite3_errmsg: It returns the description of a SQLite error.
sqlite3_finalize: It deletes a prepared statement from memory.

sqlite3_close: It closes an open database connection. It should be called after having finished any data exchange with the database, as it releases any reserved system resources.

UITableviewDelegate and UITableViewDataSource Methods

Ans : 

UITableview's Delegate Methods :

The UIViewController in which UITableView you use must adopt the UITableViewDelegate protocol. Optional methods of the protocol allow the delegate to manage selections, configure section headings and footers, help to delete and reorder cells, and perform other actions.

Configuring Rows for the Table View

- tableView:heightForRowAtIndexPath:

- tableView:indentationLevelForRowAtIndexPath:

- tableView:willDisplayCell:forRowAtIndexPath:

Managing Accessory Views

- tableView:accessoryButtonTappedForRowWithIndexPath:

- tableView:accessoryTypeForRowWithIndexPath: Deprecated in iOS 3.0

Managing Selections

- tableView:willSelectRowAtIndexPath:

- tableView:didSelectRowAtIndexPath:

- tableView:willDeselectRowAtIndexPath:

- tableView:didDeselectRowAtIndexPath:

Modifying the Header and Footer of Sections

- tableView:viewForHeaderInSection:

- tableView:viewForFooterInSection:

- tableView:heightForHeaderInSection:

- tableView:heightForFooterInSection:

Editing Table Rows

- tableView:willBeginEditingRowAtIndexPath:

- tableView:didEndEditingRowAtIndexPath:

- tableView:editingStyleForRowAtIndexPath:

- tableView:titleForDeleteConfirmationButtonForRowAtIndexPath:

- tableView:shouldIndentWhileEditingRowAtIndexPath:

Reordering Table Rows

- tableView:targetIndexPathForMoveFromRowAtIndexPath:toProposedIndexPath:

Copying and Pasting Row Content

- tableView:shouldShowMenuForRowAtIndexPath:

- tableView:canPerformAction:forRowAtIndexPath:withSender:

- tableView:performAction:forRowAtIndexPath:withSender: 

UITableview's Data Source Methods : The NSTableViewDataSource protocol declares the methods that an instance of NSTableView that provides the data to a table view and allows editing of the contents of its data source object.

All the methods are described in the following.

Getting Values

- numberOfRowsInTableView: (Required)

- numberOfSectionInTableView:

- cellForRowAtIndexPath : (Required)

- tableView:objectValueForTableColumn:row:

Setting Values

- tableView:setObjectValue:forTableColumn:row:

Implementing Pasteboard Support

- tableView:pasteboardWriterForRow:

Drag and Drop

- tableView:acceptDrop:row:dropOperation:

- tableView:namesOfPromisedFilesDroppedAtDestination:forDraggedRowsWithIndexes:

- tableView:validateDrop:proposedRow:proposedDropOperation:

- tableView:writeRowsWithIndexes:toPasteboard:

- tableView:draggingSession:willBeginAtPoint:forRowIndexes:

- tableView:updateDraggingItemsForDrag:

- tableView:draggingSession:endedAtPoint:operation:

Sorting

- tableView:sortDescriptorsDidChange:

Tips : UITableViewDelegate has no any required methods.