Add changelog entry, expand docs a bit

drift/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 1.6.0-dev
 
+- Add the `unique()` method to columns and the `uniqueKeys` override to tables
+  to define unique constraints in Dart tables.
 - Add the very experimental `package:drift/wasm.dart` library. It uses WebAssembly
   to access sqlite3 without any external JavaScript libraries, but requires you to
   add a [WebAssembly module](https://github.com/simolus3/sqlite3.dart/tree/main/sqlite3#wasm-web-support)

drift/lib/src/dsl/columns.dart

@@ -95,8 +95,8 @@ extension BuildColumn<T> on ColumnBuilder<T> {
   /// [constraint] if that is desired.
   ///
   /// This can be used to implement constraints that drift does not (yet)
-  /// support (e.g. unique keys, etc.). If you've found a common use-case for
-  /// this, it should be considered a limitation of drift itself. Please feel
+  /// support. If you've found a common use-case for  this, it should be
+  /// considered a limitation of drift itself. Please feel
   /// free to open an issue at https://github.com/simolus3/drift/issues/new to
   /// report that.
   ///
@@ -253,6 +253,9 @@ extension BuildGeneralColumn<T> on _BaseColumnBuilder<T> {
   ColumnBuilder<T?> nullable() => _isGenerated();
 
   /// Adds UNIQUE constraint to column.
+  ///
+  /// Unique constraints spanning multiple keys can be added to a table by
+  /// overriding [Table.uniqueKeys].
   ColumnBuilder<T?> unique() => _isGenerated();
 
   /// Uses a custom [converter] to store custom Dart objects in a single column

drift/lib/src/dsl/table.dart

@@ -62,7 +62,13 @@ abstract class Table extends HasResultSet {
   @visibleForOverriding
   Set<Column>? get primaryKey => null;
 
+  /// Unique constraints in this table.
+  ///
+  /// When two rows have the same value in _any_  set specified in [uniqueKeys],
+  /// the database will reject the second row for inserts.
+  ///
   /// Override this to specify unique keys:
+  ///
   /// ```dart
   /// class IngredientInRecipes extends Table {
   ///  @override
@@ -73,10 +79,14 @@ abstract class Table extends HasResultSet {
   ///  IntColumn get ingredient => integer()();
   ///
   ///  IntColumn get amountInGrams => integer().named('amount')();
-  ///}
   /// ```
+  ///
   /// The getter must return a list of set literals using the `=>` syntax so
   /// that the drift generator can understand the code.
+  ///
+  /// Note that individual columns can also be marked as unique with
+  /// [BuildGeneralColumn.unique]. This is equivalent to adding a single-element
+  /// set to this list.
   @visibleForOverriding
   List<Set<Column>>? get uniqueKeys => null;
 

drift_dev/test/cli/migrate_test.dart

@@ -262,7 +262,8 @@ dependency_overrides:
   moor:
     path: /foo/bar
   moor_generator:
-    hosted: foo
+    hosted:
+      url: foo
     version: ^1.2.3
 ''');
 
@@ -288,7 +289,8 @@ dependency_overrides:
   drift:
     path: /foo/bar
   drift_dev:
-    hosted: foo
+    hosted:
+      url: foo
     version: ^1.2.3
 '''),
     ]).validate();