diff --git a/CHANGELOG.md b/CHANGELOG.md
index 042688f..1217fb4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,24 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [4.0.0] - 2025-01-03
+### Changed
+- `getMap()` is no longer abstract and returns an empty array by default,
+so it is no longer necessary to implement for read-only APIs.
+- If the ID column is returned from `getMap()`, it is now automatically writable
+without having to set a `writableId` flag.
+- `getSelectMap()` now returns an empty array by default (rather than the `getMap()` value),
+so it is no longer necessary to implement this method just to prevent selecting write-only
+properties when using `getSelectProps()`.
+
+> [!Important]
+> When upgrading, remove readonly ID properties from `getMap()`, and implement
+> `getSelectMap()` if any writable property is not returned by `getSelectProps()`.
+
+### Removed
+- Unnecessary `getDefaultValues()` method. Defaults can be set via `processValues()` instead.
+- `writableId` bool property.
+
 ## [3.0.0] - 2024-10-29
 ### Added
 - Official support for PostgreSQL.
@@ -187,6 +205,7 @@ return early if passed an empty IDs array.
 - Initial stable release
 
 
+[4.0.0]: https://github.com/devtheorem/phaster/compare/v3.0.0...v4.0.0
 [3.0.0]: https://github.com/devtheorem/phaster/compare/v2.9.0...v3.0.0
 [2.9.0]: https://github.com/devtheorem/phaster/compare/v2.8.0...v2.9.0
 [2.8.0]: https://github.com/devtheorem/phaster/compare/v2.7.0...v2.8.0
diff --git a/src/Entities.php b/src/Entities.php
index afa0075..eddc200 100644
--- a/src/Entities.php
+++ b/src/Entities.php
@@ -8,15 +8,8 @@
 
 abstract class Entities
 {
-    /**
-     * Returns a map of properties to columns for the current table
-     * @return array<string, mixed>
-     */
-    abstract protected function getMap(): array;
-
     protected PeachySql $db;
     public string $idField = 'id';
-    protected bool $writableId = false;
     private string $idColumn;
     /** @var array<string, Prop> */
     private array $fullPropMap;
@@ -37,25 +30,13 @@ public function __construct(PeachySql $db)
         $propMap = Helpers::propListToPropMap([...array_values($bcProps), ...$selectProps]);
 
         if (!isset($propMap[$this->idField])) {
-            throw new \Exception('Missing required id property in map');
-        }
-
-        $map = $this->getMap();
-
-        if (isset($map[$this->idField])) {
-            /** @psalm-suppress MixedAssignment */
-            $this->idColumn = $map[$this->idField];
-
-            if (!$this->writableId) {
-                unset($map[$this->idField]); // prevent modifying identity column
-            }
-        } else {
-            $idParts = explode('.', $propMap[$this->idField]->col);
-            $this->idColumn = array_pop($idParts);
+            throw new \Exception("Missing required {$this->idField} property in select map");
         }
 
+        $idParts = explode('.', $propMap[$this->idField]->col);
+        $this->idColumn = array_pop($idParts);
         $this->fullPropMap = $propMap;
-        $this->map = $map;
+        $this->map = $this->getMap();
     }
 
     /**
@@ -66,6 +47,15 @@ protected function getTableName(): string
         return (new \ReflectionClass($this))->getShortName();
     }
 
+    /**
+     * Returns a map of properties to writable columns for the current table.
+     * @return array<string, mixed>
+     */
+    protected function getMap(): array
+    {
+        return [];
+    }
+
     /**
      * Returns the identity increment value of the table
      */
@@ -99,12 +89,12 @@ protected function getDefaultSort(): array
     }
 
     /**
-     * Can be used to return a separate property map for filtering/sorting (but not inserting/updating)
+     * Returns a map of properties to columns for selecting/filtering/sorting.
      * @return array<string, mixed>
      */
     protected function getSelectMap(): array
     {
-        return $this->getMap();
+        return [];
     }
 
     /**
diff --git a/test/DbTestCase.php b/test/DbTestCase.php
index a9cdf47..f90168f 100644
--- a/test/DbTestCase.php
+++ b/test/DbTestCase.php
@@ -322,7 +322,7 @@ public function testModernUsers(): void
 
         $db->insertRow('UserThings', ['user_id' => $ids[3]]);
 
-        $actual = $entities->getEntitiesByIds([$ids[2], $ids[3]], ['id', 'name', 'isDisabled', 'computed', 'weight', 'thing.uid']);
+        $actual = $entities->getEntitiesByIds([$ids[2], $ids[3]], ['id', 'name', 'isDisabled', 'computed', 'thing.uid']);
 
         $expected = [
             [
@@ -330,7 +330,6 @@ public function testModernUsers(): void
                 'name' => 'Modern user 4',
                 'isDisabled' => false,
                 'computed' => 41.0,
-                'weight' => $db->options->floatSelectedAsString ? '40' : 40.0,
                 'thing' => [
                     'uid' => $ids[3],
                 ],
@@ -340,7 +339,6 @@ public function testModernUsers(): void
                 'name' => 'Modern user 3 modified',
                 'isDisabled' => false,
                 'computed' => 31.0,
-                'weight' => $db->options->floatSelectedAsString ? '30' : 30.0,
                 'thing' => null,
             ],
         ];
diff --git a/test/src/ModernUsers.php b/test/src/ModernUsers.php
index 7b52347..0fa730f 100644
--- a/test/src/ModernUsers.php
+++ b/test/src/ModernUsers.php
@@ -14,7 +14,6 @@ protected function getTableName(): string
     protected function getMap(): array
     {
         return [
-            'id' => 'user_id',
             'name' => 'name',
             'birthday' => 'dob',
             'weight' => 'weight',
@@ -31,11 +30,12 @@ protected function getSelectProps(): array
 
         return [
             new Prop('id', 'u.user_id'),
-            new Prop('name', 'name', false, true, 'username'),
-            new Prop('isDisabled', 'is_disabled', false, true, '', 'bool'),
-            new Prop('computed', '', false, true, '', null, false, $getValue, ['weight']),
+            new Prop('name', 'name', alias: 'username'),
+            new Prop('weight', 'weight'),
+            new Prop('isDisabled', 'is_disabled', type: 'bool'),
+            new Prop('computed', getValue: $getValue, dependsOn: ['weight']),
             new Prop('thing.id', 'ut.thing_id', true),
-            new Prop('thing.uid', 'ut.user_id', false, true, 'thing_user'),
+            new Prop('thing.uid', 'ut.user_id', alias: 'thing_user'),
         ];
     }
 
diff --git a/test/src/Users.php b/test/src/Users.php
index caf13f5..1f3fbed 100644
--- a/test/src/Users.php
+++ b/test/src/Users.php
@@ -10,7 +10,6 @@ class Users extends Entities
     protected function getMap(): array
     {
         return [
-            'id' => 'user_id',
             'name' => 'name',
             'birthday' => 'dob',
             'weight' => 'weight',
@@ -18,6 +17,11 @@ protected function getMap(): array
         ];
     }
 
+    protected function getSelectMap(): array
+    {
+        return ['id' => 'user_id', ...$this->getMap()];
+    }
+
     protected function getSelectProps(): array
     {
         return [