1: <?php
2: /**
3: * CDbDataReader class file
4: *
5: * @author Qiang Xue <qiang.xue@gmail.com>
6: * @link http://www.yiiframework.com/
7: * @copyright 2008-2013 Yii Software LLC
8: * @license http://www.yiiframework.com/license/
9: */
10:
11: /**
12: * CDbDataReader represents a forward-only stream of rows from a query result set.
13: *
14: * To read the current row of data, call {@link read}. The method {@link readAll}
15: * returns all the rows in a single array.
16: *
17: * One can also retrieve the rows of data in CDbDataReader by using foreach:
18: * <pre>
19: * foreach($reader as $row)
20: * // $row represents a row of data
21: * </pre>
22: * Since CDbDataReader is a forward-only stream, you can only traverse it once.
23: *
24: * It is possible to use a specific mode of data fetching by setting
25: * {@link setFetchMode FetchMode}. See {@link http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php}
26: * for more details.
27: *
28: * @property boolean $isClosed Whether the reader is closed or not.
29: * @property integer $rowCount Number of rows contained in the result.
30: * @property integer $columnCount The number of columns in the result set.
31: * @property mixed $fetchMode Fetch mode.
32: *
33: * @author Qiang Xue <qiang.xue@gmail.com>
34: * @package system.db
35: * @since 1.0
36: */
37: class CDbDataReader extends CComponent implements Iterator, Countable
38: {
39: private $_statement;
40: private $_closed=false;
41: private $_row;
42: private $_index=-1;
43:
44: /**
45: * Constructor.
46: * @param CDbCommand $command the command generating the query result
47: */
48: public function __construct(CDbCommand $command)
49: {
50: $this->_statement=$command->getPdoStatement();
51: $this->_statement->setFetchMode(PDO::FETCH_ASSOC);
52: }
53:
54: /**
55: * Binds a column to a PHP variable.
56: * When rows of data are being fetched, the corresponding column value
57: * will be set in the variable. Note, the fetch mode must include PDO::FETCH_BOUND.
58: * @param mixed $column Number of the column (1-indexed) or name of the column
59: * in the result set. If using the column name, be aware that the name
60: * should match the case of the column, as returned by the driver.
61: * @param mixed $value Name of the PHP variable to which the column will be bound.
62: * @param integer $dataType Data type of the parameter
63: * @see http://www.php.net/manual/en/function.PDOStatement-bindColumn.php
64: */
65: public function bindColumn($column, &$value, $dataType=null)
66: {
67: if($dataType===null)
68: $this->_statement->bindColumn($column,$value);
69: else
70: $this->_statement->bindColumn($column,$value,$dataType);
71: }
72:
73: /**
74: * Set the default fetch mode for this statement
75: * @param mixed $mode fetch mode
76: * @see http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php
77: */
78: public function setFetchMode($mode)
79: {
80: $params=func_get_args();
81: call_user_func_array(array($this->_statement,'setFetchMode'),$params);
82: }
83:
84: /**
85: * Advances the reader to the next row in a result set.
86: * @return array|false the current row, false if no more row available
87: */
88: public function read()
89: {
90: return $this->_statement->fetch();
91: }
92:
93: /**
94: * Returns a single column from the next row of a result set.
95: * @param integer $columnIndex zero-based column index
96: * @return mixed|false the column of the current row, false if no more row available
97: */
98: public function readColumn($columnIndex)
99: {
100: return $this->_statement->fetchColumn($columnIndex);
101: }
102:
103: /**
104: * Returns an object populated with the next row of data.
105: * @param string $className class name of the object to be created and populated
106: * @param array $fields Elements of this array are passed to the constructor
107: * @return mixed|false the populated object, false if no more row of data available
108: */
109: public function readObject($className,$fields)
110: {
111: return $this->_statement->fetchObject($className,$fields);
112: }
113:
114: /**
115: * Reads the whole result set into an array.
116: * @return array the result set (each array element represents a row of data).
117: * An empty array will be returned if the result contains no row.
118: */
119: public function readAll()
120: {
121: return $this->_statement->fetchAll();
122: }
123:
124: /**
125: * Advances the reader to the next result when reading the results of a batch of statements.
126: * This method is only useful when there are multiple result sets
127: * returned by the query. Not all DBMS support this feature.
128: * @return boolean Returns true on success or false on failure.
129: */
130: public function nextResult()
131: {
132: if(($result=$this->_statement->nextRowset())!==false)
133: $this->_index=-1;
134: return $result;
135: }
136:
137: /**
138: * Closes the reader.
139: * This frees up the resources allocated for executing this SQL statement.
140: * Read attempts after this method call are unpredictable.
141: */
142: public function close()
143: {
144: $this->_statement->closeCursor();
145: $this->_closed=true;
146: }
147:
148: /**
149: * whether the reader is closed or not.
150: * @return boolean whether the reader is closed or not.
151: */
152: public function getIsClosed()
153: {
154: return $this->_closed;
155: }
156:
157: /**
158: * Returns the number of rows in the result set.
159: * Note, most DBMS may not give a meaningful count.
160: * In this case, use "SELECT COUNT(*) FROM tableName" to obtain the number of rows.
161: * @return integer number of rows contained in the result.
162: */
163: public function getRowCount()
164: {
165: return $this->_statement->rowCount();
166: }
167:
168: /**
169: * Returns the number of rows in the result set.
170: * This method is required by the Countable interface.
171: * Note, most DBMS may not give a meaningful count.
172: * In this case, use "SELECT COUNT(*) FROM tableName" to obtain the number of rows.
173: * @return integer number of rows contained in the result.
174: */
175: public function count()
176: {
177: return $this->getRowCount();
178: }
179:
180: /**
181: * Returns the number of columns in the result set.
182: * Note, even there's no row in the reader, this still gives correct column number.
183: * @return integer the number of columns in the result set.
184: */
185: public function getColumnCount()
186: {
187: return $this->_statement->columnCount();
188: }
189:
190: /**
191: * Resets the iterator to the initial state.
192: * This method is required by the interface Iterator.
193: * @throws CException if this method is invoked twice
194: */
195: public function rewind()
196: {
197: if($this->_index<0)
198: {
199: $this->_row=$this->_statement->fetch();
200: $this->_index=0;
201: }
202: else
203: throw new CDbException(Yii::t('yii','CDbDataReader cannot rewind. It is a forward-only reader.'));
204: }
205:
206: /**
207: * Returns the index of the current row.
208: * This method is required by the interface Iterator.
209: * @return integer the index of the current row.
210: */
211: public function key()
212: {
213: return $this->_index;
214: }
215:
216: /**
217: * Returns the current row.
218: * This method is required by the interface Iterator.
219: * @return mixed the current row.
220: */
221: public function current()
222: {
223: return $this->_row;
224: }
225:
226: /**
227: * Moves the internal pointer to the next row.
228: * This method is required by the interface Iterator.
229: */
230: public function next()
231: {
232: $this->_row=$this->_statement->fetch();
233: $this->_index++;
234: }
235:
236: /**
237: * Returns whether there is a row of data at current position.
238: * This method is required by the interface Iterator.
239: * @return boolean whether there is a row of data at current position.
240: */
241: public function valid()
242: {
243: return $this->_row!==false;
244: }
245: }
246: