Supported sqlite extensions

When analyzing .drift files, the generator can consider sqlite3 extensions that might be present. The generator can't know about the sqlite3 library your database is talking to though, so it makes a pessimistic assumption of using an old sqlite3 version without any enabled extensions by default. When using a package like sqlite3_flutter_libs, you get the latest sqlite3 version with the json1 and fts5 extensions enabled. You can inform the generator about this by using build options.

json1

To enable the json1 extension in drift files and compiled queries, modify your build options to include json1 in the sqlite_module section.

The sqlite extension doesn't require any special tables and works on all text columns. In drift files and compiled queries, all json functions are available after enabling the extension.

Since the json extension is optional, enabling it in Dart requires a special import, package:drift/extensions/json1.dart. An example that uses json functions in Dart is shown below:

import 'package:drift/drift.dart';
import 'package:drift/extensions/json1.dart';

class Contacts extends Table {
    IntColumn get id => integer().autoIncrement()();
    TextColumn get data => text()();
}

@DriftDatabase(tables: [Contacts])
class Database extends _$Database {
  // constructor and schemaVersion omitted for brevity

  Future<List<Contacts>> findContactsWithNumber(String number) {
    return (select(contacts)
      ..where((row) {
        // assume the phone number is stored in a json key in the `data` column
        final phoneNumber = row.data.jsonExtract<String, StringType>('phone_number');
        return phoneNumber.equals(number);
      })
    ).get();
  }
}

You can learn more about the json1 extension on sqlite.org.

fts5

The fts5 extension provides full-text search capabilities in sqlite tables. To enable the fts5 extension in drift files and compiled queries, modify the build options to include fts5 in the sqlite_module section.

Just like you'd expect when using sqlite, you can create a fts5 table in a drift file by using a CREATE VIRTUAL TABLE statement.

CREATE VIRTUAL TABLE email USING fts5(sender, title, body);

Queries on fts5 tables work like expected:

emailsWithFts5: SELECT * FROM email WHERE email MATCH 'fts5' ORDER BY rank;

The bm25, highlight and snippet functions from fts5 can also be used in custom queries.

It's not possible to declare fts5 tables, or queries on fts5 tables, in Dart. You can learn more about the fts5 extension on sqlite.org.

geopoly

The Geopoly module is an alternative interface to the R-Tree extension that uses the GeoJSON notation (RFC-7946) to describe two-dimensional polygons. Geopoly includes functions for detecting when one polygon is contained within or overlaps with another, for computing the area enclosed by a polygon, for doing linear transformations of polygons, for rendering polygons as SVG, and other similar operations.

To enable the geopoly extension in drift files and compiled queries, modify the build options to include geopoly in the sqlite_module section.

An example of creating a virtual table using this extension:

create virtual table geo using geopoly(geoID, a, b);

Sqlite will accept any types in additional columns (geoID, a, b from the example above), so drift will generate a DriftAny type for these columns, which is not always convenient. To avoid this, you can add types as in this example:

create virtual table geo using geopoly (
    geoID INTEGER not null,
    a INTEGER,
    b
);

This will add hints to column types and then the Dart code will be more convenient to use

You can learn more about the geopoly extension on sqlite.org.