diff --git a/DataStorage/Database/Schema/Builder.php b/DataStorage/Database/Schema/Builder.php
index b221b5eea..2bbb42e84 100644
--- a/DataStorage/Database/Schema/Builder.php
+++ b/DataStorage/Database/Schema/Builder.php
@@ -87,6 +87,30 @@ class Builder extends QueryBuilder
      */
     public bool $createTableSettings = true;
 
+    /**
+     * Table to alter.
+     *
+     * @var string
+     * @since 1.0.0
+     */
+    public string $alterTable = '';
+
+    /**
+     * Column to alter.
+     *
+     * @var string
+     * @since 1.0.0
+     */
+    public string $alterColumn = '';
+
+    /**
+     * Data to add.
+     *
+     * @var array
+     * @since 1.0.0
+     */
+    public array $alterAdd = [];
+
     /**
      * Constructor.
      *
@@ -262,16 +286,42 @@ class Builder extends QueryBuilder
     }
 
     /**
-     * Alter a field.
+     * Alter a table.
      *
-     * @param array $column Column data
+     * @param string $table Table
      *
-     * @return void
+     * @return self
      *
      * @since 1.0.0
      */
-    public function alter(array $column) : void
+    public function alterTable(string $table) : self
     {
+        $this->type       = QueryType::ALTER;
+        $this->alterTable = $table;
+
+        return $this;
+    }
+
+    /**
+     * Add a constraint
+     *
+     * @param string $key          Key
+     * @param string $foreignTable Foreign table
+     * @param string $foreignKey   Foreign key
+     *
+     * @return self
+     *
+     * @since 1.0.0
+     */
+    public function addConstraint(string $key, string $foreignTable, string $foreignKey, string $constraint = null) : self
+    {
+        $this->alterAdd['type']         = 'CONSTRAINT';
+        $this->alterAdd['key']          = $key;
+        $this->alterAdd['foreignTable'] = $foreignTable;
+        $this->alterAdd['foreignKey']   = $foreignKey;
+        $this->alterAdd['constraint']   = $constraint;
+
+        return $this;
     }
 
     /**
diff --git a/DataStorage/Database/Schema/Grammar/Grammar.php b/DataStorage/Database/Schema/Grammar/Grammar.php
index a92afed8e..aa3932b38 100644
--- a/DataStorage/Database/Schema/Grammar/Grammar.php
+++ b/DataStorage/Database/Schema/Grammar/Grammar.php
@@ -84,6 +84,20 @@ class Grammar extends QueryGrammar
         'selectFields',
     ];
 
+    /**
+     * Alter components.
+     *
+     * @var string[]
+     * @since 1.0.0
+     */
+    protected array $alterComponents = [
+        'alterTable',
+        'alterColumn',
+        'alterAdd',
+        'alterRename',
+        'alterRemove',
+    ];
+
     /**
      * {@inheritdoc}
      */
@@ -100,11 +114,95 @@ class Grammar extends QueryGrammar
                 return $this->createTablesComponents;
             case QueryType::DROP_TABLE:
                 return $this->dropTableComponents;
+            case QueryType::ALTER:
+                return $this->alterComponents;
             default:
                 return parent::getComponents($type);
         }
     }
 
+    /**
+     * Compile alter table query.
+     *
+     * @param BuilderAbstract $query Query
+     * @param string          $table Table to alter
+     *
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    protected function compileAlterTable(BuilderAbstract $query, string $table) : string
+    {
+        return 'ALTER TABLE ' . $this->expressionizeTableColumn([$table]);
+    }
+
+    /**
+     * Compile alter column query.
+     *
+     * @param BuilderAbstract $query  Query
+     * @param string          $column Column to alter
+     *
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    protected function compileAlterColumn(BuilderAbstract $query, string $column) : string
+    {
+        return '';
+    }
+
+    /**
+     * Compile alter add query.
+     *
+     * @param BuilderAbstract $query Query
+     * @param array           $add   Add data
+     *
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    protected function compileAlterAdd(BuilderAbstract $query, array $add) : string
+    {
+        switch ($add['type']) {
+            case 'COLUMN':
+                return $this->addColumn($add);
+            case 'CONSTRAINT':
+                return $this->addConstraint($add);
+            default:
+                return '';
+        }
+    }
+
+    /**
+     * Add a new column.
+     *
+     * @param array $add Add data
+     *
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    private function addColumn(array $add) : string
+    {
+        return 'ADD ' . $this->expressionizeTableColumn([$add['name']]) . ' ' . $add['datatype'];
+    }
+
+    /**
+     * Add a new constraint/foreign key.
+     *
+     * @param array $add Add data
+     *
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    private function addConstraint(array $add) : string
+    {
+        return 'ADD' . (isset($add['constraint']) ? 'CONSTRAINT ' . $add['constraint'] : '') . ' FOREIGN KEY (' .  $this->expressionizeTableColumn([$add['key']]) . ') REFERENCES '
+            . $this->expressionizeTableColumn([$add['foreignTable']])
+            . ' (' . $this->expressionizeTableColumn([$add['foreignKey']]) . ')';
+    }
+
     /**
      * Compile create table query.
      *
diff --git a/DataStorage/Database/Schema/Grammar/MysqlGrammar.php b/DataStorage/Database/Schema/Grammar/MysqlGrammar.php
index 99fa410d6..660db1347 100644
--- a/DataStorage/Database/Schema/Grammar/MysqlGrammar.php
+++ b/DataStorage/Database/Schema/Grammar/MysqlGrammar.php
@@ -39,6 +39,23 @@ class MysqlGrammar extends Grammar
      */
     protected string $systemIdentifier = '`';
 
+    /**
+     * Compile remove
+     *
+     * @param Builder $query  Builder
+     * @param array   $remove Remove data
+     *
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    protected function compileAlterRemove(BuilderAbstract $query, array $remove) : string
+    {
+        $keyWord = $remove['type'] === 'CONSTRAINT' ? 'FOREIGN KEY ' : 'COLUMN';
+
+        return 'DROP ' . $keyWord . ' ' . $remove['identifier'];
+    }
+
     /**
      * Compile from.
      *