Vector Similarity Search

Oracle EF Core 9 supports VectorDistance, VectorEmbedding, and ToVector EF functions with dense Oracle Database vectors. Default vector type mappings change from .NET string to primitive array types.

Starting with Oracle EF Core 23.8, Oracle Database sparse vectors are supported as well. This release also supports a native OracleVector provider type for dense vectors and OracleSparseVector provider type for sparse vectors for use with EF Core.

Complex types: GroupBy and ExecuteUpdate

Complex types gain new Oracle EF Core support in two ways: grouping by a complex type instance and updating by using ExecuteUpdate.

Prune Unneeded SQL Elements

In earlier EF Core releases, generated SQL contained unnecessary elements. Oracle EF Core 9 prunes these unnecessary tables and projection columns. This results in more compact and sometimes more efficient SQL.

In table pruning, unneeded tables in SQL JOINs are removed.

In projection pruning, unneeded projection columns in subqueries are eliminated.

Force or Prevent Query Parameterization

Oracle EF Core can use the EF.Constant or EF.Parameter methods to direct the generated query to use a parameter value (EF.Constant) or parameter variable (EF.Parameter). Oracle EF Core 9 introduces EF.Parameter support.

Inlined Uncorrelated Subqueries

In EF Core 8, an IQueryable interface referenced in another LINQ is executed in a separate database round trip. This results in multiple round trips and slows performance.

Oracle EF Core 9 enables the sub-query (IQueryable) and the LINQ executions in a single round trip.

Queries Using Count != 0 Optimization

In Oracle EF Core 8, LINQ queries could be translated to use the SQL COUNT function. In EF Core 9, these LINQ queries will use the more efficient SQL EXISTS.

New ToHashSetAsync<T> Methods

Oracle EF Core adds an asynchronous version of Enumerable.ToHashSet<T>. This method returns query results as a HashSet.

Improved Data Seeding

Oracle EF Core has an easy way to populate a database with an initial data set. This is known as data seeding. DbContextOptionsBuilder introduces new UseSeeding and UseAsyncSeeding methods that are executed when the DbContext initializes during an EnsureCreated or EnsureCreatedAsync operation.

Auto-Compiled Models and MSBuild Integration

Compiled EF Core models enhance app startup time for large models with hundreds of entity types. Previously, compiled models were generated manually using the command line. EF Core then was directed to use them with the UseModel method.

Oracle EF Core 9 can detect and use compiled models automatically, eliminating the need for UseModel. Moreover, if entity types or DbContext are changed, MSBuild automatically updates the compiled model when the model project is built.

Make Existing Model Building Conventions More Extensible

Oracle EF Core 9 makes it easier to extend some of the public model-building conventions, such as the property mapping code.

Update ApplyConfigurationsFromAssembly to Call Non-Public Constructors

The ApplyConfigurationsFromAssembly method can now be instantiated from a non-public constructor, as well as the public, parameterless form of this constructor has improved error messages during failed instantiations.

Not Supported Features

The Oracle EF Core 9 provider does not support the following features:

• Protection against concurrent migrations, also known as database lock during migrations

• Read-only primitive collections