dbcontext

EF Core – Inheritance mapping

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There are two ways to do inheritance mapping in EF Core: Let’s say we have a database with employees. All employees have an id and a name. There are currently two types of employees: programmers and drivers. Programmers have a language (ex: C#), and drivers have a car (ex: Honda). We can model this with … Read more

SqlException: Cannot insert explicit value for identity column

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When you have a table with an identity column, and you try to specify the value for identity column when inserting a record, you’ll get the following exception: Microsoft.Data.SqlClient.SqlException (0x80131904): Cannot insert explicit value for identity column in table ‘Movies’ when IDENTITY_INSERT is set to OFF. This error means you have an identity column in … Read more

EF Core – Apply migrations programmatically

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In EF Core, you create migrations when you are first creating the database and tables and also for any database schema changes. DbContext.Database has a few methods you can call to manage migrations programmatically. To apply any pending migrations: If the database doesn’t exist, MigrateAsync() will create it and then apply the migrations. To check … Read more

EF Core – Database schema changes

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Anytime you change the definition of the database – from renaming a column to creating a table – it’s referred to as a database schema change. With EF Core, you deal with database schema changes by using migrations. When you first create the database with EF Core, you create a migration that contains the initial … Read more

EF Core – How to create a database and a table

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In this article, I’ll show how to use EF Core to create a database with one table in it. At the end, I’ll show a standalone console app that inserts a record into this database. Note: I’ll be using SQL Server. I haven’t tried this with other database providers. Please leave a comment if you’re … Read more