Copy Updated Database into device in ios sdk - iphone

Question

In my app, i used the sqlite DB. I submitted the 1.0 version of the app to app store. But after that i made some changes into DB like Inserting some new rows.
Then submitted 1.1 version of the app. But i will not able to get updated DB because the old DB already exists in device.
How can i solve this?
If i delete the app & then install the new version of app, then i got the updated DB.
//My code for copy of DB is as follow:
- (void)createEditableCopyOfDatabaseIfNeeded
{
// First, test for existence.
BOOL success;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:#"xxx.sqlite"];
success = [fileManager fileExistsAtPath:writableDBPath];
if (success) return;
// The writable database does not exist, so copy the default to the appropriate location.
NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"xxx.sqlite"];
success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
if (!success) {
NSAssert1(0, #"Failed to create writable database file with message '%#'.", [error localizedDescription]);
}
}
I called this method in appDidFinishLaunching method.
How can i get updated DB without deleting the app when new version is available

Answer 1

You can use the NSUserDefaults for doing this.
In your new version add this code:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
if(![[NSUserDefaults standardUserDefaults] boolForKey:#"1.1"]])
{
[self removeDatabase];
[self createEditableCopyOfDatabaseIfNeeded];
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:#"1.1"];
}
//Other stuffs
}
Method for removing the old database file:
- (void)removeDatabase
{
BOOL success;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *removeDBPath = [documentsDirectory stringByAppendingPathComponent:#"xxx.sqlite"];
success = [fileManager fileExistsAtPath:writableDBPath];
if(success)
{
[fileManager removeItemAtPath:writableDBPath error:&error]
}
}

Answer 2

You will need to perform a database migration so that old users of your app do not lose their data.
This means checking which version of the database already exists, and executing the necessary SQL statements to update the schema and data.
The MTMigration framework (MIT license) can help you execute code once per version of your app, for example:
[MTMigration migrateToVersion:#"1.1" block:^{
// migrate the SQL database here
}];
But you may wish to detect the version of your database differently.
It would be a good idea to write some unit tests for this procedure. Screwing up user data is the last thing you want to do.

Answer 3

You have to write Data migration script:-
In case when you need to make changes to an exiting table which contains some data then you need to do some steps as follows:
1) Rename the existing table
Say TableName was 'TestTable', So Rename the table to 'TestTableOld'
2) Create a new table called 'TestTable' which has the new columns you want and other altercations made.
3) Copy data from 'TestTableOld' to 'TestTable' with the query like:
Insert into TestTable('col1',col2'...'coln') Values Select col1, col2, col3,...'coln' From TestTableOld;
And newly added column set value as blank, as for new entries will use as such.
4) Drop the table 'TestTableOld'
Follow the above four step procedure as this would work as an alter statement and also it would preserve all your data from your original table.
If you are using User_Version, then would helpfull to identify old DB with new DB