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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