I have an SSDT Database project, to which I have added a new field. If I use that DACPAC to generate a new database on my local server, the new field is all present and correct - which is great.
However, if I upgrade a database, then at the point when the system is checking for differences, it reports back that there have been no changes (misses my new field), and of course my new field doesn't appear.
Does anyone know why that would be, or have any thoughts on what it is that I might be doing wrong?
Related
We have a Windows 8.1 universal app published on the Windows store. Due to a requirement change now we need to add some fields to an existing table. We have used SQLite for Windows Runtime (Windows 8.1) and SQLite for Windows Phone 8.1. Now if we add some new fields to an existing table (by updating the model classes) will that cause any issues when the existing users update the app?
Instead of adding new columns if we create a new table, then can that cause any issue or will that be safer than adding new fields?
Adding a new column to an existing table is perfectly safe even with an existing SQLite database. Same goes for creating a new table. The concrete process depends on which SQLite library you are using.
If you are querying the database directly using SQL queries, then you will use ALTER TABLE ... ADD COLUMN query. If you are using library like sqlite-net-pcl, you get automatic migrations out of the box when you run the CreateTable method. As documentation says:
The automatic migration, currently, only supports adding new columns. If your classes have new properties that are not associated with columns in the table, then alter table ... add column commands will be executed to bring the database up to date. These new columns will not have default values and will therefore be null.
Tip
When you change the model, always test out the changes against the previous version of the database. This can be done in two ways:
Install the existing version from Store, launch the app and use it so that it contains some data, then close it and go to C:\Users\[UserName]\AppData\Local\Packages. Here navigate to Packages and there find your app's package folder. Inside go to LocalState where you should find your sqlite database. Copy it somewhere, uninstall the Store version and launch the new version for debugging and place a breakpoint in the App.xaml.cs constructor. When the debugger stops there, copy the original database back to the same location in app package LocalState folder and continue debugging. Observe if the database is migrated properly.
Using Git source control, go in history to the previous release commit, install the app for debugging, fill the DB with some data, close the app. Now go to the latest commit and launch app for debugging again. Verify the migration works.
I have deployed the 1st version of my wp8 in wp store and now i want to deploy the update version of it. Though I know the process of update deployment, but my concern is the sqlite file which doesn't get updated.
Here is the scenario, I have sqlite file in the app where user can store config and setting, in new version I added extra tables and I want to these tables should be reflected in the the update without affecting user settings and config.
What points I should consider to take care of this issue?
Thanks!
Assuming the data in the sqlite database is static you can give the database a new name and submit it with the updated app. One first run copy the new database to isolated storage and delete the old version of the database to save space.
If the user is inputting data into the database you will have to include code to modify the database structure on the first run and insert any records into the new table
Very simply: What is the "correct" location to create SQLite database tables in a Firefox addon.
(If possible, I would like to create tables on installation of the addon).
It is best to create tables right before you start using the database. You cannot assume that doing it once (when the extension is installed) is sufficient - the user might remove your database later for one reason or another. So you would do something like this:
var dbConn = Services.storage.openDatabase(file);
if (!dbConn.tableExists("foo"))
{
// Database isn't initialized, do it now
dbConn.createTable("foo", "...");
}
This is also how I would update the database structure on extension updates - if after opening the database you see that the database structure is outdated then you update it. This way you will correctly handle the scenario that your extension was updated but the database was downgraded later at some point because of a backup being restored.
I had a website, with an sql server database. I decided to create a new version of the site, so I downloaded the database + website onto my local dev PC, and added a whole bunch of stuff to both - in particular, I added lots of new stored procedures, columns and tables to the database, while leaving the existing data for the site in place while doing this.
It is now time to launch the new version. Of course, while working on the new version, the data in the database on the live site has changed - new users have signed up and so on, so I can't just push the dev enviroment database live, as this would lose data.
What is the best way to import all the data from the existing database into the new database configuration? Should I take the existing database, and then add all the columns, procs, tables, indexes and so on in to it, or is there a better way?
You can use SQL Compare or other comparison tools to make the production database look like your dev database. If budget is a concern you can see plenty of alternatives in this blog post.
In SQL Server Management Studio , right click on your local database -> Task -> Generate Scripts, and then you'll be able to select your SP/Functions and then execute these script against the production database
How to manage database changes while upgrading desktop applications?
We have a SQLite database for one of our desktop apps. The uninstaller keeps the database to be used by the next install. But what if the next install has an updated version? How to keep the data but upgrade the tables?
We use .NET and Linq2sql
Here is how I do this:
In my code I define the version of the database
#define DB_VERSION 2
This version number is incremented every time I make a change to the code that 'breaks' the database ( makes an incompatible change to the schema or the semantics of the db contents )
When the code creates a new database, it executes this SQL command
QueryFormat(L"PRAGMA SCHEMA_VERSION = %d;",DB_VERSION);
Note that this must be AFTER all CREATE TABLE commands have been executed, otherwise sqlite increments SCHEMA_VERSION.
When the code opens an existing database, the first thing it does is
Query(L"PRAGMA schema_version;")
The SCHEMA_VERSION that is returned from this query is compared with the DB_VERSION. If they do not match, then the database was created by a different software version. What happens next depends on the details of what you need. Typically:
database was created by a more recent software: inform user and exit
database was created by older software for which there is an upgrade: offer user option to run upgrade code, or re-initialize database
database was created by older software with no upgrade: offer user option to re-initialize database or exit.
The details of how the upgrade code works depends very much on what you need. In general open the old database AND open a new empty database. Read the old tables, convert the data as required, and write to the new database. Close the dbs. Delete the old db. Rename the new db to the standard db name. Open the new db.
If nothing else, the output of echo .dump | sqlite my_database.sqlite is designed to be extremely portable, even to non-SQLite databases.
Or, if I'm misreading your question, you may want alter table.