Add typed DTO selection, updates and deletes

README.md

@@ -322,6 +322,16 @@ See the [mapping and migration guide](docs/migration-guide-12.1-to-13.md#explici
 
 ### SQLite reconstruction and data types
 
+Read migration-local DTOs with `Database.Select<ScreenDto>("Common_Screens",
+x => !x.Archive && x.Id > minimumId)`. This returns a materialized list, quotes
+identifiers, parameterizes values and uses the active migration transaction.
+See [DTO queries](docs/dto-queries.md) for column mapping, supported predicates
+and SQL null semantics.
+Predicates also support literal string `Contains`, `StartsWith` and `EndsWith`.
+Typed `Update<T>(table, changes, predicate)` updates only properties assigned in
+a DTO initializer; `Delete<T>(table, predicate)` removes matching rows. Both
+require predicates, retain the migration transaction and return affected counts.
+
 Supported rebuilds retain mapped data, named/composite keys, declared column collations, supported indexes and triggers, and the AUTOINCREMENT high-water mark. Generated columns, `STRICT`, `WITHOUT ROWID` and indexes with explicit collations are rejected for reconstruction; hidden rowid values are not preserved. Foreign keys retain separate update/delete actions; unsupported `MATCH FULL`/`PARTIAL` requests fail explicitly. See the [SQLite preservation matrix](docs/migration-framework-comparison.md#what-survives-reconstructionand-what-is-not-guaranteed).
 
 CLR `Guid` defaults use the same blob representation as inserted GUID parameters. Existing text GUID defaults remain unchanged during unrelated rebuilds; converting mixed storage requires an explicit data migration. SQLite's `AsciiIgnoreCase` preset selects ASCII-only `NOCASE`; Unicode case-insensitive requests need a suitable custom collation, registered on the connection and selected by name.

docs/_src/content.py

@@ -196,6 +196,55 @@ def page(group, slug, title, summary, *sections, source="src/Migrator/Framework/
     section("Database storage differs", '<p>SQLite does not enforce declared string lengths or decimal precision. UInt64 values above Int64.MaxValue are rejected there. Oracle character empty strings become NULL; Informix and Sybase have their own trimming and range behavior. Consult the <a href="https://github.com/dotnetprojects/Migrator.NET/blob/master/docs/data-type-boundary-tests.md">type support and boundary matrix</a> for supported mappings and live-test scope. A shared DbType does not imply identical native storage.</p>'))
 
 page("Operations", "data", "Data operations", "Insert, update and delete using explicit column/value arrays. Keep predicates separate from changed values.",
+    section("Read DTOs", '<p>Select&lt;T&gt;(table, predicate) reads a single table into a materialized IReadOnlyList&lt;T&gt;, binds predicate values as native driver parameters and disposes the command and reader. DTOs need a public parameterless constructor and public readable/writable scalar properties. ColumnAttribute can override names; NotMappedAttribute excludes properties. Keep DTOs with their migration.</p><p>Predicates support direct comparisons, boolean composition, null checks and literal string Contains/StartsWith/EndsWith searches. Update&lt;T&gt; changes only initializer-assigned properties; Delete&lt;T&gt; removes matching rows. Both mutations require a predicate and return affected row counts. Other methods, joins and general LINQ operations fail explicitly. Comparisons follow database collation and SQL null semantics: Optional != 7 excludes NULL rows. Context.Select executes immediately during fluent authoring and cannot see queued operations. See the <a href="https://github.com/dotnetprojects/Migrator.NET/blob/master/docs/dto-queries.md">DTO query reference</a> for mapping and translation limits.</p>', pair("Read screens using a typed predicate", '''
+public class ReadScreens : Migration
+{
+    public sealed class ScreenDto
+    {
+        public int Id { get; set; }
+        public bool Archive { get; set; }
+        public string GenericDefinition { get; set; }
+    }
+    public override void Up()
+    {
+        var minimumId = 10;
+        var screens = Database.Select<ScreenDto>(
+            "Common_Screens", x => !x.Archive && x.Id > minimumId);
+        var matching = Database.Select<ScreenDto>("Common_Screens",
+            x => (!x.Archive && x.Id > 4) || x.GenericDefinition.Contains("aa"));
+        int updated = Database.Update<ScreenDto>("Common_Screens",
+            x => new ScreenDto { Archive = true },
+            x => x.GenericDefinition.StartsWith("old"));
+        int deleted = Database.Delete<ScreenDto>("Common_Screens",
+            x => x.Archive && x.GenericDefinition.EndsWith(".obsolete"));
+    }
+    public override void Down() { }
+}
+''', '''
+public class ReadScreens : FluentMigration
+{
+    public sealed class ScreenDto
+    {
+        public int Id { get; set; }
+        public bool Archive { get; set; }
+        public string GenericDefinition { get; set; }
+    }
+    public override void BuildUp(MigrationBuilder migration)
+    {
+        var minimumId = 10;
+        var screens = Context.Select<ScreenDto>(
+            "Common_Screens", x => !x.Archive && x.Id > minimumId);
+        var matching = Context.Select<ScreenDto>("Common_Screens",
+            x => (!x.Archive && x.Id > 4) || x.GenericDefinition.Contains("aa"));
+        int updated = Context.Update<ScreenDto>("Common_Screens",
+            x => new ScreenDto { Archive = true },
+            x => x.GenericDefinition.StartsWith("old"));
+        int deleted = Context.Delete<ScreenDto>("Common_Screens",
+            x => x.Archive && x.GenericDefinition.EndsWith(".obsolete"));
+    }
+    public override void BuildDown(MigrationBuilder migration) { }
+}
+''', kind="class")),
     section("Insert rows", '<p>Column and value arrays must have the same length. The provider binds values using its driver-specific parameter mappings. For multiple rows issue multiple Insert.IntoTable(...).Row(...) expressions. Each Row completes one insert; its returned builder offers only IfNotExists, so a second Row cannot silently replace the first. Insert, update and delete each expose only their supported steps.</p>', pair("Insert a user", '''
 Database.Insert("Users", new[] { "Id", "Name" }, new object[] { 1, "Ada" });
 ''', '''