5/3/2023 0 Comments Seed data generator![]() Your database provider typically takes care of the necessary configuration for example, a numeric primary key in SQL Server is automatically set up to be an IDENTITY column.įor more information, see the documentation about keys and guidance for specific inheritance mapping strategies. HasComputedColumnSql("LEN() + LEN()", stored: true) īy convention, non-composite primary keys of type short, int, long, or Guid are set up to have values generated for inserted entities if a value isn't provided by the application. You may also specify that a computed column be stored (sometimes called persisted), meaning that it is computed on every update of the row, and is stored on disk alongside regular columns: modelBuilder.Entity() ![]() The above creates a virtual computed column, whose value is computed every time it is fetched from the database. On most relational databases, a column can be configured to have its value computed in the database, typically with an expression referring to other columns: modelBuilder.Entity() You can also specify a SQL fragment that is used to calculate the default value: protected override void OnModelCreating(ModelBuilder modelBuilder) You can configure a default value on a property: protected override void OnModelCreating(ModelBuilder modelBuilder) On relational databases, a column can be configured with a default value if a row is inserted without a value for that column, the default value will be used. ![]() This page details various patterns for configuration value generation with EF Core. Database columns can have their values generated in various ways: primary key columns are frequently auto-incrementing integers, other columns have default or computed values, etc.
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