iOS-How to keep update Sqlite Database with new version - ios

In my new version add some new table and some new fields is existing .How to save to crashed and keep update with new version.


When you application working with sqlite, before insert/update data in to table you can check that new row is already exist on table or not. if not you can add it new row in existing table.
Same way Table already exist or not you can check before any operation in table.Bashed on that you can create new table or update in existing one.


You have to do some logics to maintain the version updates.
First in your new version, check the code(Xcode) version number with the App Store version by using this code, refer check current app version. (Apple api is available)
If the version mismatches, then you have to update the database and get all the datas from server whichever needed for new version.
This process you have to check in appdelegate.
Note: Instead of api call, you can store the version number in the database, and compare the Xcode version.

Related

Table Updates Made in SQLiteStudio Not Recognized by iOS Mobile Application

I am working on a iOS mobile application using Xcode as the IDE and Swift as the language of choice. I added a column to the SQLite database that interacts with my application but unfortunately when I attempt to perform any database operations through the application the column is not recognized.
The following error is sent:
DB Error: 1 "table xyz has no column named column_name"
When I added the column I also increased the database version or user_version in SQLiteStudio.
Is there something else I should be doing to cause the application to recognize the changes? I know uninstalling and reinstalling would work but that is not an option of course as I cannot lose the data currently housed in the database. My other idea was to put all the data in temporary variables or something like that, drop and recreate the tables and reinsert the data. I wasn't sure if this was a good course of action though. Any help with this is appreciated.

can liquibase be used to work with two different schema versions of the db at the same time?

I'm trying to overcome the following issue...
I have a MariaDB database that is used for an IOS application.
I'm about to release a new version to the apple store that uses a different version of the schema of the database. means all achievement related tables are modified.
can liquibase be used to configure the changes and allow selected users to connect and work with the schema as if the old schema version is configured, and to actually make the actual changes to the new schema?
before I release the application I need to provide apple with a test version so they will confirm it. so I want users that are connected from apple to see the new achievements features and to work with the new schema while regular users to still be able to user to previous version of the application and to work with the old schema that behind the scenes will actually update the database according to the new schema.
I hope I explained myself properly.
can Liquibase do that ? or it's just like a git for db changes ?
thank you! :)

How to Migrate an entity in Coredata where destination entity's model is just created

I have a model Version. The entity passPhrase of Version needs to be migrated to New entity passPhrase in Home model.
But the Home model is introduced in new version of database. It was not present in old xcdatamodel. How can I migrate data from
Version.passPhrase to Home.passPhrase

And the golden rule of CoreData migration is - avoid custom migration at any cost. :)
So the way to do this to use lightweight migration to add your new entity, and then just use a one off migration script to move your data over.
You can remove the passPhrase property from your Version class definition but you need to leave it in the model for now so you can still access the old data. This can be cleaned up at some time in the future when you are confident all of your users have upgraded to the newer version, or just leave it there forever.
To access the existing value during your copy just use [version valueForKey:#"passPhrase"] and then once copied clear it out the same way [version setValue:nil forKey:#"passPhrase"]

In core data, Changing Entity / Model mapping does not comes under light weight migration. You have to handle it manually by subclassing NSMigrationManager and implementing custom NSEntityMigrationPolicy.
Apple provides little documentation on the subject.Please check the Custom Core data migration with detailed example. Hope this will help.

Updating new version to app store with different sqlite db structure

I have uploaded an app on app store (version 1.0). My app is using a sqlite database for storing some data. Now, I have made some changes in the database (I have added 2 or 3 new columns in one of the tables in my db). I want to update the previous version of my app with the new version 1.1 (which is having different db structure). Now, when the users which are already using the version 1.0 upgrade the app to version 1.1, the db is already present in app sandbox and hence, the app is pointing to version 1.1, but my db is still the old one. I want to have the new db with the old data, if any. Please help me out. Thanks.

sqlite supports something called as user_version property, you can execute PRAGMA user_version to query for current schema version of your app db. This query can happen write at the beginning when your app starts.
to update this user_version execute following update query PRAGMA user_version = version_num;
Whenever you create sqlite db, it is best practice to put this property user_version, so that when you are upgrading in future you can query current value. Check what it's needs to be and execute remaining alter or create tables to upgrade your schema version.
For example:
In first release I create table1 with col1, col2
I execute sql to create table1 and once it is successfully done, i execute pragma user_version = 1. so this will indicate my current schema version is 1
In future release i add new col3, i need to change my schema version to 2
I first query user_version, check it's value and if it is 1, then you need to run alter script to add new column and set user version to 2.
In your case, since you haven't set the user_version before, it would be difficult to differentiate new install vs an upgrade scenario. So for now may be you assume if db is present it is upgrade scenario and execute alter scripts and if not present assume it is a new
install scenario and run create scripts. But see if you can use above pragma to solve your problem in future atleast.

You could check on launch if it's the old db, and if so have a routine to create a new db with the new structure (with a temporary name), copy all the data from the old to the new, close the old db & delete it, close the new db, rename it, then finally open it again for your updated app to use. Easy, fast, & you don't need an in-depth knowledge of SQLite to do it.

Is SQLite Manager refreshing itself properly?

I added new rows to my database through SQLiteManager but I cannot see those values in my tableview. My old values are seen. More interestingly, I deleted my database file but I can see my old values again in my tableview. When I created new database with new name, it sees that. How can I make it perceive new values?

Not directly an answer as there are at least two SQLite Managers.
SQLiteManager (standalone) and SQLite Manager the Firefox Plugin.
If you haven't tried the Firefox Plugin yet I'd strongly recommend doing so. I'm very happy with it and have never touched another SQLite Browser since.

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