[5.7] Add computed support to SQL Server schema grammar

src/Illuminate/Database/Schema/Blueprint.php

@@ -822,6 +822,18 @@ public function unsignedDecimal($column, $total = 8, $places = 2)
         ]);
     }
 
+    /**
+     * Create a new generated computed column on the table.
+     *
+     * @param  string  $column
+     * @param  string  $expression
+     * @return \Illuminate\Database\Schema\ColumnDefinition
+     */
+    public function computed($column, $expression)
+    {
+        return $this->addColumn('computed', $column, compact('expression'));
+    }
+
     /**
      * Create a new boolean column on the table.
      *

src/Illuminate/Database/Schema/ColumnDefinition.php

@@ -24,6 +24,7 @@
  * @method ColumnDefinition unsigned() Set the INTEGER column as UNSIGNED (MySQL)
  * @method ColumnDefinition useCurrent() Set the TIMESTAMP column to use CURRENT_TIMESTAMP as default value
  * @method ColumnDefinition virtualAs(string $expression) Create a virtual generated column (MySQL)
+ * @method ColumnDefinition persisted() Mark the computed generated column as persistent (SQL Server)
  */
 class ColumnDefinition extends Fluent
 {

src/Illuminate/Database/Schema/Grammars/Grammar.php

@@ -2,6 +2,7 @@
 
 namespace Illuminate\Database\Schema\Grammars;
 
+use RuntimeException;
 use Illuminate\Support\Fluent;
 use Doctrine\DBAL\Schema\TableDiff;
 use Illuminate\Database\Connection;
@@ -190,6 +191,18 @@ public function prefixArray($prefix, array $values)
         }, $values);
     }
 
+    /**
+     * Create the column definition for a generated computed column type.
+     *
+     * @param  \Illuminate\Support\Fluent  $column
+     *
+     * @throws \RuntimeException
+     */
+    protected function typeComputed(Fluent $column)
+    {
+        throw new RuntimeException('The database driver in use does not support the computed type.');
+    }
+
     /**
      * Wrap a table in keyword identifiers.
      *

src/Illuminate/Database/Schema/Grammars/MySqlGrammar.php

@@ -2,6 +2,7 @@
 
 namespace Illuminate\Database\Schema\Grammars;
 
+use RuntimeException;
 use Illuminate\Support\Fluent;
 use Illuminate\Database\Connection;
 use Illuminate\Database\Schema\Blueprint;
@@ -833,6 +834,18 @@ public function typeMultiPolygon(Fluent $column)
         return 'multipolygon';
     }
 
+    /**
+     * Create the column definition for a generated computed column type.
+     *
+     * @param  \Illuminate\Support\Fluent  $column
+     *
+     * @throws \RuntimeException
+     */
+    protected function typeComputed(Fluent $column)
+    {
+        throw new RuntimeException('The database driver in use requires a type, see virtualAs/storedAs modifiers.');
+    }
+
     /**
      * Get the SQL for a generated virtual column modifier.
      *

src/Illuminate/Database/Schema/Grammars/SqlServerGrammar.php

@@ -19,7 +19,7 @@ class SqlServerGrammar extends Grammar
      *
      * @var array
      */
-    protected $modifiers = ['Increment', 'Collate', 'Nullable', 'Default'];
+    protected $modifiers = ['Increment', 'Collate', 'Nullable', 'Default', 'Persisted'];
 
     /**
      * The columns available as serials.
@@ -733,6 +733,17 @@ public function typeMultiPolygon(Fluent $column)
         return 'geography';
     }
 
+    /**
+     * Create the column definition for a generated computed column type.
+     *
+     * @param  \Illuminate\Support\Fluent  $column
+     * @return string|null
+     */
+    protected function typeComputed(Fluent $column)
+    {
+        return "as ({$column->expression})";
+    }
+
     /**
      * Get the SQL for a collation column modifier.
      *
@@ -756,7 +767,9 @@ protected function modifyCollate(Blueprint $blueprint, Fluent $column)
      */
     protected function modifyNullable(Blueprint $blueprint, Fluent $column)
     {
-        return $column->nullable ? ' null' : ' not null';
+        if ($column->type !== 'computed') {
+            return $column->nullable ? ' null' : ' not null';
+        }
     }
 
     /**
@@ -787,6 +800,20 @@ protected function modifyIncrement(Blueprint $blueprint, Fluent $column)
         }
     }
 
+    /**
+     * Get the SQL for a generated stored column modifier.
+     *
+     * @param  \Illuminate\Database\Schema\Blueprint  $blueprint
+     * @param  \Illuminate\Support\Fluent  $column
+     * @return string|null
+     */
+    protected function modifyPersisted(Blueprint $blueprint, Fluent $column)
+    {
+        if ($column->persisted) {
+            return ' persisted';
+        }
+    }
+
     /**
      * Wrap a table in keyword identifiers.
      *

tests/Database/DatabaseSqlServerSchemaGrammarTest.php

@@ -770,6 +770,17 @@ public function testAddingMultiPolygon()
         $this->assertEquals('alter table "geo" add "coordinates" geography not null', $statements[0]);
     }
 
+    public function testAddingGeneratedColumn()
+    {
+        $blueprint = new Blueprint('products');
+        $blueprint->integer('price');
+        $blueprint->computed('discounted_virtual', 'price - 5');
+        $blueprint->computed('discounted_stored', 'price - 5')->persisted();
+        $statements = $blueprint->toSql($this->getConnection(), $this->getGrammar());
+        $this->assertCount(1, $statements);
+        $this->assertEquals('alter table "products" add "price" int not null, "discounted_virtual" as (price - 5), "discounted_stored" as (price - 5) persisted', $statements[0]);
+    }
+
     public function testGrammarsAreMacroable()
     {
         // compileReplace macro.