Full-Text Search is a feature of Microsoft SQL Server that lets you perform search engine like queries against the string properties of your entities.

The Full-Text feature isn’t available on the LocalDB (the version of SQL Server that comes with Visual Studio). I like to use Developer Edition on Docker for local development.

docker run -d -p 1433:1433 -e SA_PASSWORD=Password12! -e ACCEPT_EULA=Y mcr.microsoft.com/mssql/server

Use this connection string to connect to the docker image.

Data Source=(local)\MSSQLSERVER;Initial Catalog=BlogsDatabase;User ID=sa;Password=Password12!

Now that we’ve got the prerequisites installed, let’s assume we’re starting with a Post entity type that has a Content property we’d like to search.

class Post
    public int Id { get; set; }
    public string Content { get; set; }

First, we need to add a full-text index to the Content column. Do this by adding a new Migration.

dotnet ef migrations add AddFullTextIndexToPostContent

Inside the Up method of the migration, add the following.

    suppressTransaction: true);

    sql: "CREATE FULLTEXT INDEX ON Posts(Content) KEY INDEX PK_Posts;",
    suppressTransaction: true);

The first operation adds a full-text catalog. This serves as a container for any full-text indexes.

The second operation creates the full-text index enabling queries on the column.

Neither operation can be executed inside a transaction, so we need to suppress the migration’s transaction. Warning, this currently doesn’t work when applying migrations during publish from Visual Studio (see dotnet/sdk#12676).

Don’t forget to apply the migration.

dotnet ef database update

To issue a full-text query from EF, use the Contains or FreeText functions:

var results = from p in db.Posts
              where EF.Functions.FreeText(p.Content, query)
              select p;

The query string has an entire syntax of its own. Check out the Full-Text Query documentation to learn more.

Happy searching!