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diff --git a/markers.go b/markers.go
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+// SPDX-FileCopyrightText: 2026 Stefan Majewsky <majewsky@gmx.net>
+// SPDX-License-Identifier: Apache-2.0
+
+package oblast
+
+// seal is a private type that appears in interface definitions below,
+// to ensure that only types from this package can implement these interfaces.
+type seal struct{}
+
+// TableInfo is a marker for struct types that correspond to tables.
+// Put this as an embedded field on your struct type and put the table name in the field's `db` tag.
+//
+//	// For example, this struct type...
+//	type LogEntry struct {
+//		oblast.TableInfo      `db:"log_entries"`
+//		oblast.PrimaryKeyInfo `db:"id"`
+//		ID                    int64     `db:"id,auto"`
+//		CreatedAt             time.Time `db:"created_at"`
+//		Message               string    `db:"message"`
+//	}
+//	// ...corresponds to this table schema (shown here in PostgreSQL syntax):
+//	CREATE TABLE log_entries (
+//		id          BIGSERIAL    NOT NULL PRIMARY KEY,
+//		created_at  TIMESTAMPTZ  NOT NULL,
+//		message     TEXT         NOT NULL
+//	);
+//
+// This marker is required for all operations that use autogenerated SQL statements.
+type TableInfo struct{}
+
+// isTable implements the IsTable interface.
+func (TableInfo) isTable(seal) {}
+
+// IsTable is implemented by all types that have an embedded field of type [TableInfo].
+type IsTable interface {
+	isTable(seal)
+}
+
+// PrimaryKeyInfo is a marker for struct types that correspond to tables with a primary key.
+// Put this as an embedded field on your struct type and list the columns of the primary key in the field's `db` tag,
+// as shown on the example for type [TableInfo].
+//
+// This marker is required for all UPDATE and DELETE operations that use autogenerated SQL statements.
+type PrimaryKeyInfo struct{}