How to Alter a Trigger in SSDT - sql-server-data-tools

I am a C# developer, and would rather use VS 15 and SSDT than SSMS.
However, I don't understand how I should be doing an "Alter Trigger..." script.
For example, In Sql Object Explorer, I select Design, and the Designer opens. I then click on the trigger on the right hand side, and it displays a create script for the trigger.
However, I don't want to create it, I want to alter the existing one. So I change "create" to "alter", thinking that should run. However, an error is thrown:
This statement is not recognized in this context.
Should I be using SSMS for this type of activity?
The only workaround I could come up with is changing the name of the existing trigger, and then running the create statement instead of an alter statement.
I am just wondering what the workflow is supposed to be on this.

When you deploy an SSDT project it takes the model in the SSDT project, compares it to the database and then automatically generates the upgrade script.
So what you do is write "create trigger" and publish your database and the upgrade will either drop and create the new one or do an alter for you.
If you haven't deployed to your database yet I would suggest generating a script rather than publishing it and verifying what is in there first. :)

Related

Schema not updating when publish web app from Visual Studio

I am building an ASP.NET MVC EF app with code-first migrations and hosting it in Azure with Azure SQL DB. The first time I published this, it went fine. But since then my models changed, and my schema in the Azure DB is not getting updated to match. When I deploy, I do have "Execute Code First Migrations" checked. When that wouldn't work, I deleted my DB and then recreated it in the Azure portal, figuring that would trigger it getting updated. But then that didn't work, so I set AutomaticMigrationsEnabled = True in the migration Configuration. It is STILL not working, so currently my DB in Azure has none of my tables. HOW can I get the DB in Azure to be forced to update to match my models so the published site will work?? I did try looking for if there's a way to script the VS local DB to a Create query and execute that in SQL management studio, but couldn't find how to do that.
If you have made sure that you have selected update database in the publish setting, and the connection string is correctc and its still not updating. Maybe the following will help for you:
I sometimes get an issue like this, it is quite frustrating, My publish file is correct and my settings are set to allow SQL updates to occur during publishing. But sometimes the database hasn't been updated and I get a nice "backing context has changed" error, sometimes the culprit is the migration table that hasn't been updated. Unfortunately the only sure way to get your databases in sync is to check what migration history they are both at, by comparing [dbo].[__MigrationHistory]
If your published server is missing the latest migration history, then you can generate an SQL script of that by typing into the package manager console:
Update-Database -Script -TargetMigration [migration name]
'migration name' should be the name of the last migration that your published server had, visual studio will generate sql script that can be used to bring the database up to the latest migration from that target migration.
Sometimes (though very rarely, its only happened once or twice for me) the above doesn't work for whatever reason (usually because migration files have been deleted), if that is the case then its a good idea to script the whole database, and cherry pick the sql you need from that.
Update-Database -Script -SourceMigration:0
This will generate a script for every migration, you can then cherry pick based on the changes you've made. The 'latest' changes will be closer to the bottom of the file. every migrational change will start with an if check:
IF #CurrentMigration < '201710160826338_mymigration'
BEGIN
You can use this to pick the bits that you need, if you do pick the SQL be sure to include the update to the migration history. It will be at the end of the if block and look something like this:
INSERT [dbo].[__MigrationHistory]([MigrationId], [ContextKey], [Model], [ProductVersion])
VALUES (N'201710101645265_test', N'API.Core.Configuration', 'Some long checksum')
Including the migration history will ensure that visual studio doesn't have the problem again.
Hope this helps.

Code First and Existing Database with Data

I'm developing a windows application which uses SQL Server Database. I have different versions of this application and they have different database structure, so I need to migrate database to the latest version on application start. I want to compare the database structure with the application model, then do alter, create or drop commands.
Also I want to use EF Code-First ORM, after some search I've figured it out that there are some useful commands and configs in code first. But the problem is, as I know, all of them drop the existing database and create a new one so the data will be lost while I need the data.
I used these lines in my application start function:
var migrator = new DbMigrator(new Configuration());
migrator.Update();
But after execution this line I will get this exception:
There is already an object named 'SomeTable' in the database.
I know that, it's right and there is that table but in structure is changed! How can I compare the structure and do the rest?
That's not how migrations work. You need a migration for every version of your database so EF can check the __MigrationHistory table and see if it has been applied. If your initializer is set to MigrateDatabaseToLatestVersion your database won't be recreated on model changes.
You could try to recreate the history: roll back to your oldest database, add a migration, add 2nd oldest version changes, create a 2nd migration, etc.
Another option is to add a migration for where you are now, generate a script (update-database -Script) then comment out the stuff that exists in each deployed database before applying it.
Yet another option would be to use the VS Schema compare utility against each database and your current database to get the changes over. Then apply a baseline migration to each (add-migration Initial -IgnoreChanges).
Now moving forward you can generate a series of migrations and your code should work as expected.

How to debug a trigger in SQL Server what is executed by an ASP Web app?

Context:
I have a (legacy) ASP.NET app using a class lib which's data access is calling SPs using ad dal.dbml and its generated code.
I am using VS 2015 Enterprise update 1, have locally installed Microsoft SQL Server 2014 - 12.0.4213.0 (X64) (Build 10586) and SSMS 2014.
Question
When running the Web application the app inserts rows to a table which I recently implemented an insert trigger. How can I debug the actual trigger execution "triggered" by the Web application?
Note: I do know how to interactively debug SPs in SSMS. Now that is not I want, because It is nearly impossible to reproduce and parametrize what the web app does. So I would like to debug via the Web App.
Is this possible at all? (Seems to be a pretty usual need, though I unserstand it requires very complex debugging infrastructure and services)
What you do is you run Profiler to get the typical values being sent when the error occurs.
Then the easiest way I know of to troubleshoot something like this is to take the trigger code out of the trigger and put it in a script using #inserted (and/or #deleted if need be) instead of the pseudotables accessed by the trigger.
The insert the data the stored proc would insert into the table into the #inserted table. Then you can take the trigger step by step and even look at the results of a select that is used in an insert.
The most common error I have found in triggers is that they are set up to handle only one record in inserted rather than multiple records. SO if you find that what your proc would put in for the values you get is one record, that may be the issue. Or you may be missing a required field. IN that case you may need adjust the proc to put in the value or assign a default.

How to work with LocalDB and EF, without using migrations

I am on VS 2012 RTM, with EF 5. I am doing Code First, but trying to ignore Code Migrations since I am just in development. To avoid them, I have this set
Database.SetInitializer(new DropCreateDatabaseIfModelChanges<SomeContext>());
Occasionally, even when I don't think I've touched the model, it decides to recreate. That's fine. But it usually results in the error
Cannot drop database because it is currently in use.
So I decided to delete the database entirely. I go into VS, go to the "SQL Server Object Explorer", find the DB and delete it. Now I'm stuck at
Cannot attach the file '{0}' as database '{1}'
I had this happen last night and I just fiddled around until it work (shut down tasks, restart VS, changed the DB and file names in the web.config, etc.
So question 1) How do I get out of this state?
But the more important question, how do I prevent myself from getting in this state at all?
The SQL Server Object Explorer window can hold a connection to the database. Closing the window and all windows opened from it releases the connection.
I had the same problem and managed to fix it. The main problem is that EF won't automatically create the database. The solution is not very hard.
First, go to the Solution Explorer and manually create the database. To do this, go to the folder where your database is located (usually App_Data). Right-click on this folder and click on Add -> New Item. Select the Data tab and select SQL Server Database. Make sure you enter the name Entity Framework expects (which is specified in the Cannot attach the file '{0}' as database '{1}' error message).
Then most likely you will get an error message that says that the database does not contain any model metadata. To circumvent this, change your database initialisation to:
Database.SetInitializer(new DropCreateDatabaseAlways<SomeContext>());
Now run the application and the database should be there with tables correctly created. Once this step has been successfully executed, you change change your database initializer back to:
Database.SetInitializer(new DropCreateDatabaseIfModelChanges<SomeContext>());

Updating SQL Server database with SQL scripts

I have a number of manually written scripts (.sql) for tables, views and stored procedures that are used from an ASP.NET application. These scripts drop the object and recreates them. I need a way to update the database when the scripts change without deleting the object. For example, when a column is added to an existing table that has rows in it, I would need to update this table with this extra column without losing the rows.
I need a way to "update" the database on a single click (I can hook up the changes using a batch file). Does Visual Studio support this kind of functionality?
If you get Visual Studio Team System - Database Edition 2008 - which is now bundled with "Developer Edition" for free - it handles that. Visual Studio database projects without that edition really just store the static SQL that you want to track. The Database Edition is capable of determining the 'deltas' between your SQL and what's in a target database, generating that script, and executing against your database. You do get the option of reviewing that generated SQL, but by default it is very safe [it won't run if it thinks that there will be any data lost].
Yes - it's called Database Projects.
You can define a Visual Studio Database Projects, have create and change SQL scripts inside it, and then execute those against a database connection of your choice when you need to.
See this blog post here for a great explanation, or read the whole series that the 4 guys from Rolla wrote.

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