Postgre & SQLSRV - Should Never Have A Field Length For TEXT

system/Database/Postgre/Forge.php

@@ -130,7 +130,7 @@ protected function _alterTable(string $alterType, string $table, $field)
     protected function _processColumn(array $field): string
     {
         return $this->db->escapeIdentifiers($field['name'])
-            . ' ' . $field['type'] . $field['length']
+            . ' ' . $field['type'] . ($field['type'] === 'text' ? '' : $field['length'])
             . $field['default']
             . $field['null']
             . $field['auto_increment']

system/Database/SQLSRV/Forge.php

@@ -144,7 +144,25 @@ protected function _alterTable(string $alterType, string $table, $field)
                 }
             }
 
-            $sql = 'ALTER TABLE ' . $this->db->escapeIdentifiers($this->db->schema) . '.' . $this->db->escapeIdentifiers($table) . ' DROP ';
+            $fullTable = $this->db->escapeIdentifiers($this->db->schema) . '.' . $this->db->escapeIdentifiers($table);
+
+            // Drop default constraints
+            $fields = implode(',', $this->db->escape((array) $field));
+
+            $sql = <<<SQL
+                SELECT name
+                FROM SYS.DEFAULT_CONSTRAINTS
+                WHERE PARENT_OBJECT_ID = OBJECT_ID('{$fullTable}')
+                AND PARENT_COLUMN_ID IN (
+                SELECT column_id FROM sys.columns WHERE NAME IN ({$fields}) AND object_id = OBJECT_ID(N'{$fullTable}')
+                )
+                SQL;
+
+            foreach ($this->db->query($sql)->getResultArray() as $index) {
+                $this->db->query('ALTER TABLE ' . $fullTable . ' DROP CONSTRAINT ' . $index['name'] . '');
+            }
+
+            $sql = 'ALTER TABLE ' . $fullTable . ' DROP ';
 
             $fields = array_map(static fn ($item) => 'COLUMN [' . trim($item) . ']', (array) $field);
 
@@ -263,7 +281,7 @@ protected function _processColumn(array $field): string
     {
         return $this->db->escapeIdentifiers($field['name'])
             . (empty($field['new_name']) ? '' : ' ' . $this->db->escapeIdentifiers($field['new_name']))
-            . ' ' . $field['type'] . $field['length']
+            . ' ' . $field['type'] . ($field['type'] === 'text' ? '' : $field['length'])
             . $field['default']
             . $field['null']
             . $field['auto_increment']

tests/system/Database/Live/ForgeTest.php

@@ -1355,4 +1355,21 @@ public function testDropKey()
 
         $this->forge->dropTable('key_test_users', true);
     }
+
+    public function testAddTextColumnWithConstraint()
+    {
+        // some DBMS do not allow a constraint for type TEXT
+        $result = $this->forge->addColumn('user', [
+            'text_with_constraint' => ['type' => 'text', 'constraint' => 255, 'default' => ''],
+        ]);
+
+        $this->assertTrue($this->db->fieldExists('text_with_constraint', 'user'));
+
+        // SQLSRV requires dropping default constraint before dropping column
+        $result = $this->forge->dropColumn('user', 'text_with_constraint');
+
+        $this->db->resetDataCache();
+
+        $this->assertFalse($this->db->fieldExists('text_with_constraint', 'user'));
+    }
 }

user_guide_src/source/changelogs/v4.3.0.rst

@@ -70,6 +70,7 @@ Others
 - Added new Form helper function :php:func:`validation_errors()`, :php:func:`validation_list_errors()` and :php:func:`validation_show_error()` to display Validation Errors.
 - Now you can autoload helpers by **app/Config/Autoload.php**.
 - ``BaseConnection::escape()`` now excludes the ``RawSql`` data type. This allows passing SQL strings into data.
+- SQLSRV now automatically drops ``DEFAULT`` constraint when using ``Forge::dropColumn()``.
 - Added :ref:`Time::toDatabase() <time-todatabase>` to get a datetime string that can be used with databases regardless of locale.
 
 Changes