* [refactor] Refactor SQL processing for database installation and upgrade

- Extract SQL processing methods to install model for better reusability
- Add replaceContantsInSQL() and appendMySQLTableOptions() public methods
- Unify SQL constants replacement across installation and upgrade modules
- Remove duplicate SQL processing code in extension and upgrade models
- Fix __TABLE__ to __DATABASE__ in zentao.sql for consistency
- Improve code maintainability and reduce duplication

module/install/model.php

@@ -123,9 +123,8 @@ class installModel extends model
         {
             $this->dbh->useDB($this->config->db->name);
 
-            $dbCharset = $this->dbh->getDatabaseCharsetAndCollation($this->config->db->name);
-            $dbFile    = $this->app->getAppRoot() . 'db' . DS . 'zentao.sql';
-            $tables    = explode(';', file_get_contents($dbFile));
+            $dbFile = $this->app->getAppRoot() . 'db' . DS . 'zentao.sql';
+            $tables = explode(';', file_get_contents($dbFile));
 
             foreach($tables as $table)
             {

module/upgrade/model.php

@@ -16,15 +16,6 @@ class upgradeModel extends model
 {
     static $errors = array();
 
-    /**
-     * 数据库版本。
-     * Database version.
-     *
-     * @var string
-     * access public
-     */
-    public $databaseVersion = '';
-
     public $fromVersion = '';
 
     public $fromEdition = '';
@@ -40,7 +31,6 @@ class upgradeModel extends model
     {
         parent::__construct();
         $this->loadModel('setting');
-        $this->databaseVersion = $this->loadModel('install')->getDatabaseVersion();
     }
 
     /**
@@ -10854,7 +10844,8 @@ class upgradeModel extends model
     {
         if($this->config->db->driver != 'mysql') return true;
 
-        if(version_compare($this->databaseVersion, '5.6', '<')) return true;
+        $dbVersion = $this->loadModel('install')->getDatabaseVersion();
+        if(version_compare($dbVersion, '5.6', '<')) return true;
 
         /* 获取服务器的字符集和排序规则。Get server charset and collation. */
         $result          = $this->dbh->getServerCharsetAndCollation($this->config->db->name);