I'm learning EF Core with SQL Server and trying to generate schema diagram among POCOs. I implemented the code-first approach and want to get a schema diagram shows each entity and relations.
I tried to generate the schema from Database Management Studio, but it doesn't contain navigation properties information. So, how to do that?
You can achieve that usually by creating a physical database using dotnet ef database update or other migration method and then using your db provider to reverse engineer the schema for you. For example, if you use SQL server, there is an option to create database schema in the SQL Management Studio UI. Other DBMS will likely have similar options.
Related
We made an app in C#; we used EF but have created the models using a database-first approach. We lost the database and need to recreate it in order to continue development; how do I use the model in my database-first C# app in order to automatically create the database in SQL Server (trying to avoid tedious database and table re-creation).
Thanks in advance,
Ronan
I have a database Database named 'DatabaseEF' and another database 'DatabaseOld'.
The former is created in EntityFramework and later is a plain old database created directly in sql server.
Now we have been tasked with merging these 2 but let the old one stay the same way and should not be in EF context because it is also accessed by old ado.net drivers etc.
So how should I go about it?
As for the schema, scaffold (generate entities from existing database, aka. db-first) the old database, combine them into the EF context, and make some fixes if there are something not compatible with the new context or logically incorrect.
As for the existing data on production environment, apply the migration with ef and execute raw sql commands to transfer the data.
So I am using Neo4J and thought about how to update existing databases with schema changes e.g. a Node has new properties, edges changed, values changed, etc.
So far I was only using SQL Server and the Entity Framework includes a migration tool that can automatically write migrations when the schema changes.
How is this done in Neo4J?
E.g. a customer has v. 1.0 from our software and neo4j database. We make changes for v.1.1 and now we need to update the db from all our customers.
I am using Neo4J in C#. I have so far only found something similar for Ruby: https://neo4jrb.readthedocs.io/en/8.2.x/Migrations.html
You can use: https://www.liquigraph.org/.
Where you can create the cypher queries you need to migrate database data.
Since neo4j is basically "schema-less" (in the relational DB sense), there is no tool for migrating to a new neo4j "schema".
You will have to write code to update the DB.
I do actively maintain Neo4j-Migrations:
https://github.com/michael-simons/neo4j-migrations
It's basically an automated script runner, that stores schema versions inside the same database as a subgraph. It is also able to store them separately in a Neo4j server supporting multi databases.
As you mention that you are using C#: This tool is Java based, but I do also provide native binaries for all 3 major OSses availabe on GitHub. You might can integrate them into your workflow.
I am proficient in SQL but not so much in C#. Recently a web application has broke. I am trying to find the data in the SQL database that is entered through the web application. I am confused about where the SQL table and fields are in var query 1 and 2. See attached image.
This looks like Entity Framework, and it would depend on how the mappings are setup, this is usually done either with an EDMX, or using code first with fluent mappings.
So you'll have to look at your mappings, to see what
_ICL_RESENTS_INCOMEDTLS,
_ICL_RESENTS_PAYMENTs,
CDCLIENTS
entities are mapped to which tables. This mapping should tell you what the underlying tables are.
My application uses SQL Server Ce for the database and Entity Framework as the ORM.
Now I'm trying to switch to SQL Server Express but I'm having trouble doing so.
UPDATE
So after banging my head for 3 hours I finally figured out that you cannot use an Entity model generated from a SQL Server CE database against a SQL Server (in my case Express version).
I used a Diff program to view the generated files (Designer.cs) for both databases and I noticed these differences in the file:
SQL Server CE SQL Server
FK__Download__000000000000003F FK__Download__PlaneI__0519C6AF
So I have to create two entity models, but how can I interchange between the two in my program?
If I create two entity models, I'll have two classes with the same object names.
Thanks in advance
The EDMX file actually consists out of three parts.
CSDL, your conceptual model
SSDL, the storage model
MSL, the mapping between those two.
Normally these three parts are embedded in as a resource in your assembly and the connection string that you use tells the runtime to look for them in that assembly.
You can however use physical files and deploy them with your application. In such a way you can use the same CSDL but a different set of SSDL/MSL for the specific database. In that way you can reuse your entity model against both your SqlCE database and a SQL Server database.
Here you can find a blog post about swapping EF metadata