I have an existing database with data in it. There are (a lot of) sql files which insert a set of starting data.
The project is being refactored to code-first approach, so I wan't to move the init sql files into a context initializer.
Is there a way to achieve this with a tool or script, without having to manually re-type all the sql files?
You can use EF Migration to perform this kind of refactorization.
And on the migration, you can execute custom SQL scripts. Here is an example :
https://entityframeworkcore.com/knowledge-base/46638380/execute-custom-sql-script-as-part-of-entity-framework-migration
Related
I have created an ASP.NET Core web application using the MVC pattern (by following this tutorial) and connected it to a local database that is now populated with some data. I have two questions, if someone please help me understand and answer them:
1) My default connection string is set to the following:
"ConnectionStrings": {
"DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=aspnet-MyAppName;Trusted_Connection=True;MultipleActiveResultSets=true"
}
Is it possible, only by changing the name and path in this connection string, to re-create the exact same database elsewhere with the data that is currently stored in it (for example, as backup)?
I have found the local database here:
C:\Users\my-name\AppData\Local\Microsoft\Microsoft SQL Server Local DB\Instances\MSSQLLocalDB
But when I try to copy the .mdf file to back up the database, I get an error that says the file is open and cannot be copied. What is it open in? How can I simply back the db file up?
2) After creating a custom controller, I noticed that all the provided properties of my Personmodel are used in the auto-generated code; e.g. in my case:
public async Task<IActionResult> Create([Bind("Birthday,ID,Username,EmailAddress")] PersonModel personModel)
I thought this would mean that if we change the code in the model class, we need to search for and effect the changes accordingly, but then I realized if I want to keep using auto-generated code, I have to do all the same steps as when I am generating it for the first time, and then when it asks if I want to replace the old code with new code, I choose yes.
Is there a better way of doing this, because this would overwrite my custom code every time and destroy the data stored in my local database. Particularly, when I store data in its local database, and then I decide to change a column name or add something, this would override everything...
How do I go about this situation?
Question 1
The .mdf and other files associated with the database will be in use by the SQL Server service. If you want to take a backup, use SQL Server Management Studio - right-click the database in the object explorer, select Tasks and then Backup. If you want to use the backup database then you need to restore it - again in the object explorer, right-click the "Databases" folder and select Restore Database and then browse to wherever you created the backup file.
Question 2 (updated 7th Sep)
When you change your model classes, you can use the add-migration command in the console to generate a new migration class containing the code to transform the database from its current structure to the new structure which matches the updated models. If the migration can cause data loss, then backup the database and restore the backup under a different name before running update-database, You can then create a script to transform the data from the backup into the new structure of the updated database.
Scaffolded components are a bit different to Entity Framework migrations. Migrations are truly auto-generated classes, and most of the time you wouldn't need to update (or even look at) the generated code. Think of scaffolded components as being more like a kind of template - it's a way of getting started with the classes, methods, markup etc that you're most likely to need, which is quicker than writing it all from scratch. It's not an alternative to writing code though, the intent is that once you've created the scaffolded code, you'll maintain it manually going forward. There is no way (that I know of) to automatically update scaffolded code to match a new model whilst retaining any edits you've made to it. You have two options
Re-scaffold the code and then apply your edits to it
Update the code manually to match the new model
All you can really do is weigh up the two options and decide which one is the least effort.
In my Application I have used Entity Framework Database First approach.
Currently my application is in Dev Environment, now it need to be moved into Test Environment and later into Production Environment.
So is there anyway that I can use .net feature or Entity framework feature to migrate/create database in Test environment. Other than using SQL feature of restoring the database.
Also note that if any enhancement comes then Database structure can change, table schema can change.
So can you suggest me the best way to easily migrate database schema in different environment without losing existing Data.
If you want to take advantage of EF-Migrations feature, you must convert your application to Code First with Existing Database http://msdn.microsoft.com/en-us/data/jj200620.aspx
If you are unable to convert to code first then you must create the update script by hand.
Use a schema compare tool, compare the development and production server.
For each difference found, create an update query.
Once the entire script is finished, test it on the staging server.
Automating the migration is very risky, it depends on the type and size changes you made to the schema. You can't trust any single feature or tool specially if the changes requires data motion (moving data around).
The following links might help you:
How to do Migrations in DB first approach
EF Migrations for Database-first approach?
With Database First, the easiest way to copy a schema is to extract a data tier application in management studio, create an empty database on the target, register it as a data tier application with the same name, and upgrade the empty database using the upgraded file. You can repeat this step to manage schema changes.
Having said that, going forward you're really better off switching your Database First to Code First as it will make change management across your deployments much easier.
Migrations are best way to deal with it
Preferred way to update production db is to first generate sql file and then run the sql file in production environment.
MS had a very good artical on this
http://msdn.microsoft.com/en-in/data/jj591621.aspx#script
I started a project and use Entity Framework 5.
Now I created a database on my SQL Server Express with all tables.
Further I created the DbContext with a fluent mapping.
What is better, the fluent mappings or the .edmx mapping files?
The database is now on the SQL Server but I want support also SQL local db.
Is there a way to tell the EF that I want to use a SQL local db?
Should I ship the whole database within the setup or better to create the database on startup of my application? How can I use EF to create the database (SQL server or SQL local db)?
Every useful help would be appreciated.
If you are using EF5 I would stay away from edmx.
You could reverse engineer your model from database using Entity Framework Power Tools.
Than you can customize your model using either Data Annotations or fluent mappings.
If you use EF5 code first it can create database automatically for you if not present, however that would not work very well on subsequent upgrades (it can recreate database but then you will use or your existing data). The options you could use, is either EF migrations, where you can specify in fluent-like languagage the modifications that were made to your database or use Database Project in Visual Studio, where you can store all your schema in source control and then generate database upgrade scripts betweeen releases.
Is there a SELECT command I can execute in ADO.NET to retrieve a script that will rebuild my database from scratch with empty tables? I'd like to be able to script the creation of the database itself, along with all the tables, views, and stored procedures and any relationships that exist between the tables. Also primary key and identity specifications.
I am using SQL Server 2000 and C# (.NET Framework 2.0).
There is no such SELECT command but you can use SQL Server Management Studio to generate such a script for you.
Context menu for a database in Object Explorer has Script Database as option that should do the trick for you. Then you could execute the resulting script from your program using standard SqlCommand objects.
Depending on what you are trying to do, you may consider to build your database structure into the model (System databases / model). Then, each time you'll create a new database, you'll get all the stuff you need already inserted into your new database.
But be warned that this solution will create all the stuff for ALL the new databases created.
Using SQL Server Management Studio we have ability to script entire existing database to one sql script with all database schema and data. What I need is some tool, which will automatically create similar C# database initializer class or classes, which will represent database structure model, and fill this database with it's data. Maybe is it possible somehow to convert SQL script to C#? Any suggestions?
P.S. To create database I use EntityFramework codefirst strategy.