改进Model类，新增支持连贯操作方式查询数据的特性

MiniFramework/Library/Mini/Model.php

@@ -33,6 +33,12 @@ abstract class Model
      * @var object
      */
     protected $_dbPool;
+
+    private $_curDb;
+
+    private $_method;
+
+    private $_options;
 
     /**
      * 构造
@@ -60,4 +66,195 @@ public function loadDb($key)
 
         return $this->_dbPool[$key];
     }
+
+    /**
+     * 设置当前使用的数据库
+     * 
+     * @param string $key
+     * @param array $params
+     * @return bool | \Mini\Model
+     */
+    public function useDb($key, $params = null)
+    {
+        $db = $this->loadDb($key);
+        if ($db == null) {
+            if ($params != null) {
+                $this->_curDb = $this->regDb($key, $params);
+            } else {
+                return false;
+            }
+        } else {
+            $this->_curDb = $db;
+        }
+
+        return $this;
+    }
+
+    /**
+     * 注册数据库对象
+     * 
+     * @param string $key
+     * @param array $params
+     * @return object
+     */
+    public function regDb($key, $params)
+    {
+        $this->_dbPool[$key] = Db::factory('Mysql', $params);
+
+        return $this->_dbPool[$key];
+    }
+
+    /**
+     * 查询
+     * 
+     * @throws Exceptions
+     * @return array
+     */
+    public function select()
+    {
+        $this->_method = 'SELECT';
+        $sql = $this->createSql();
+        if ($this->_curDb) {
+            $res = $this->_curDb->query($sql, 'All');
+            return $res;
+        } else {
+            throw new Exceptions('Database is not found.');
+        }
+    }
+
+    /**
+     * 设置查询字段
+     * 
+     * @param string $field
+     * @return \Mini\Model
+     */
+    public function field($field = null)
+    {
+        if ($field != null) {
+            $this->_options['field'] = trim($field);
+        }
+
+        return $this;
+    }
+
+    /**
+     * 设置数据表
+     * 
+     * @param string $table
+     * @return \Mini\Model
+     */
+    public function table($table = null)
+    {
+        if ($table != null) {
+            $this->_options['table'] = trim($table);
+        }
+
+        return $this;
+    }
+
+    /**
+     * 设置查询条件
+     * 
+     * @param string $where
+     * @return \Mini\Model
+     */
+    public function where($where = null)
+    {
+        if ($where != null) {
+            $this->_options['where'] = trim($where);
+        }
+
+        return $this;
+    }
+
+    /**
+     * 设置分组
+     * 
+     * @param unknown $group
+     * @return \Mini\Model
+     */
+    public function group($group = null)
+    {
+        if ($group != null) {
+            $this->_options['group'] = trim($group);
+        }
+
+        return $this;
+    }
+
+    /**
+     * 设置排序
+     * 
+     * @param string $order
+     * @return \Mini\Model
+     */
+    public function order($order = null)
+    {
+        if ($order != null) {
+            $this->_options['order'] = trim($order);
+        }
+
+        return $this;
+    }
+
+    /**
+     * 设置LIMIT
+     * 
+     * @param string $limit
+     * @return \Mini\Model
+     */
+    public function limit($limit = null)
+    {
+        if ($limit != null) {
+            $this->_options['limit'] = trim($limit);
+        }
+
+        return $this;
+    }
+
+    /**
+     * 创建SQL语句
+     * 
+     * @return bool | string
+     */
+    private function createSql()
+    {
+        if (! isset($this->_options['table']) || $this->_options['table'] == '') {
+            return false;
+        }
+
+        $sql = $this->_method;
+
+        if (! isset($this->_options['where']) || $this->_options['where'] == '') {
+            $where = '';
+        } else {
+            $where = ' WHERE ' . $this->_options['where'];
+        }
+
+        if ($this->_method == 'SELECT') {
+
+            if (! isset($this->_options['field']) || $this->_options['field'] == '') {
+                $sql .= ' * ';
+            } else {
+                $sql .= ' ' . $this->_options['field'] . ' ';
+            }
+            $sql .= 'FROM ' . $this->_options['table'] . $where;
+            if (isset($this->_options['group']) && $this->_options['group'] != '') {
+                $sql .= ' GROUP BY ' . $this->_options['group'];
+            }
+            if (isset($this->_options['order']) && $this->_options['order'] != '') {
+                $sql .= ' ORDER BY ' . $this->_options['order'];
+            }
+            if (isset($this->_options['limit']) && $this->_options['limit'] != '') {
+                $sql .= ' LIMIT ' . $this->_options['limit'];
+            }
+
+        }
+
+        $this->_options = array();
+
+        $this->_method = '';
+
+        return $sql;
+    }
 }