Bsft.Data.Sqlite 2.2.0

Bsft.Data.Sqlite

The SQLite half of the Bsft.Data search family: it turns a declared search group into an FTS5 match, ranked by bm25, joined onto the caller's queryable, and gives an application's migrations the DDL that creates the FTS5 table and the triggers that keep it in step.

Install

dotnet add package Bsft.Data.Sqlite

Requires Bsft.Data (pulled transitively; it declares the search groups and validates them) and Microsoft.EntityFrameworkCore.Sqlite.

Register

services.AddBsftDataSqlite(options => options
    .HasFullTextIndex("candidates", "Candidates_fts")
    .UseTokenizer(SqliteTokenizer.Unicode61)
    .AcceptsUnstemmedLanguage("de"));

// or hand the same declaration to the container and to a migration
var search = new BsftDataSqliteOptions().HasFullTextIndex("candidates", "Candidates_fts");
services.AddBsftDataSqlite(search);

Two more things are needed. The application's migration creates the index with migrationBuilder.CreateFullTextIndex(command, search).CreateFullTextSyncTriggers(command), and its OnModelCreating maps the index table with modelBuilder.HasBsftFullTextIndex(table, columns…) — an FTS5 index is a table, and EF Core can only compose a query against a table it knows. The container receives a copy of the declaration, so a mutation after the call cannot make the provider and the migration disagree about the same index.

Configure

BsftDataSqliteOptions has no SectionName and binds from no configuration section — see the paragraph below the table.

Validation: a group name and an FTS5 table name must not be blank, the folding level must be 0, 1 or 2, and the tokenizer must be a declared value. Beyond that, SearchStartupValidator in Bsft.Data fails startup for a searchable group this package has no index declared for, and for one whose language the chosen tokenizer cannot stem unless AcceptsUnstemmedLanguage accepted it.

Every member of this type describes the schema: the tokenizer and the folding level are compiled into the FTS5 table when the migration creates it, so changing one means rebuilding the index rather than restarting the process. A deployment that could state them in a settings file could state them differently from the index it actually has, and the provider would then certify stemming for an index that has none. The declaration therefore lives beside the migration that makes it true, and there is deliberately no IConfiguration overload.

Extend

ISearchProvider is the seam, and SqliteSearchProvider is this package's implementation of it; it is contributed with TryAddEnumerable, so a host may register providers for more than one database and Bsft.Data will validate each. Nothing else here is replaceable — the tokenizer mapping and the DDL are how this package talks to FTS5, not a decision a caller makes.

Documentation

Topic page: docs/search.md. Conventions: docs/package-conventions.md.