projects / z_archive / KronOS.git / blame
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| 6 | <title>Generating Query Results : CodeIgniter User Guide</title> | |
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| 25 | <!-- START NAVIGATION --> | |
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| 28 | <div id="masthead"> | |
| 29 | <table cellpadding="0" cellspacing="0" border="0" style="width:100%"> | |
| 30 | <tr> | |
| 31 | <td><h1>CodeIgniter User Guide Version 2.1.3</h1></td> | |
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| 43 | <a href="http://codeigniter.com/">CodeIgniter Home</a> › | |
| 44 | <a href="../index.html">User Guide Home</a> › | |
| 45 | <a href="index.html">Database Library</a> › | |
| 46 | Query Results | |
| 47 | </td> | |
| 48 | <td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td> | |
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| 52 | ||
| 53 | ||
| 54 | <br clear="all" /> | |
| 55 | ||
| 56 | ||
| 57 | <!-- START CONTENT --> | |
| 58 | <div id="content"> | |
| 59 | ||
| 60 | ||
| 61 | ||
| 62 | <h1>Generating Query Results</h1> | |
| 63 | ||
| 64 | ||
| 65 | <p>There are several ways to generate query results:</p> | |
| 66 | ||
| 67 | <h2>result()</h2> | |
| 68 | ||
| 69 | <p>This function returns the query result as an array of <strong>objects</strong>, or <strong>an empty array</strong> on failure. | |
| 70 | ||
| 71 | Typically you'll use this in a foreach loop, like this:</p> | |
| 72 | ||
| 73 | <code> | |
| 74 | $query = $this->db->query("YOUR QUERY");<br /> | |
| 75 | <br /> | |
| 76 | foreach ($query->result() as $row)<br /> | |
| 77 | {<br /> | |
| 78 | echo $row->title;<br /> | |
| 79 | echo $row->name;<br /> | |
| 80 | echo $row->body;<br /> | |
| 81 | }</code> | |
| 82 | ||
| 83 | <p>The above <dfn>function</dfn> is an alias of <dfn>result_object()</dfn>.</p> | |
| 84 | ||
| 85 | <p>If you run queries that might <strong>not</strong> produce a result, you are encouraged to test the result first:</p> | |
| 86 | ||
| 87 | <code> | |
| 88 | $query = $this->db->query("YOUR QUERY");<br /> | |
| 89 | <br /> | |
| 90 | if ($query->num_rows() > 0)<br /> | |
| 91 | {<br /> | |
| 92 | foreach ($query->result() as $row)<br /> | |
| 93 | {<br /> | |
| 94 | echo $row->title;<br /> | |
| 95 | echo $row->name;<br /> | |
| 96 | echo $row->body;<br /> | |
| 97 | }<br /> | |
| 98 | } | |
| 99 | </code> | |
| 100 | ||
| 101 | <p>You can also pass a string to result() which represents a class to instantiate for each result object (note: this class must be loaded)</p> | |
| 102 | ||
| 103 | <code> | |
| 104 | $query = $this->db->query("SELECT * FROM users;");<br /> | |
| 105 | <br /> | |
| 106 | foreach ($query->result('User') as $row)<br /> | |
| 107 | {<br /> | |
| 108 | echo $row->name; // call attributes<br /> | |
| 109 | echo $row->reverse_name(); // or methods defined on the 'User' class<br /> | |
| 110 | } | |
| 111 | </code> | |
| 112 | ||
| 113 | <h2>result_array()</h2> | |
| 114 | ||
| 115 | <p>This function returns the query result as a pure array, or an empty array when no result is produced. Typically you'll use this in a foreach loop, like this:</p> | |
| 116 | <code> | |
| 117 | $query = $this->db->query("YOUR QUERY");<br /> | |
| 118 | <br /> | |
| 119 | foreach ($query->result_array() as $row)<br /> | |
| 120 | {<br /> | |
| 121 | echo $row['title'];<br /> | |
| 122 | echo $row['name'];<br /> | |
| 123 | echo $row['body'];<br /> | |
| 124 | }</code> | |
| 125 | ||
| 126 | ||
| 127 | <h2>row()</h2> | |
| 128 | ||
| 129 | <p>This function returns a single result row. If your query has more than one row, it returns only the first row. | |
| 130 | The result is returned as an <strong>object</strong>. Here's a usage example:</p> | |
| 131 | <code> | |
| 132 | $query = $this->db->query("YOUR QUERY");<br /> | |
| 133 | <br /> | |
| 134 | if ($query->num_rows() > 0)<br /> | |
| 135 | {<br /> | |
| 136 | $row = $query->row(); | |
| 137 | <br /><br /> | |
| 138 | echo $row->title;<br /> | |
| 139 | echo $row->name;<br /> | |
| 140 | echo $row->body;<br /> | |
| 141 | } | |
| 142 | </code> | |
| 143 | ||
| 144 | <p>If you want a specific row returned you can submit the row number as a digit in the first parameter:</p> | |
| 145 | ||
| 146 | <code>$row = $query->row(<dfn>5</dfn>);</code> | |
| 147 | ||
| 148 | <p>You can also add a second String parameter, which is the name of a class to instantiate the row with:</p> | |
| 149 | ||
| 150 | <code> | |
| 151 | $query = $this->db->query("SELECT * FROM users LIMIT 1;");<br /> | |
| 152 | <br /> | |
| 153 | $query->row(0, 'User')<br /> | |
| 154 | echo $row->name; // call attributes<br /> | |
| 155 | echo $row->reverse_name(); // or methods defined on the 'User' class<br /> | |
| 156 | </code> | |
| 157 | ||
| 158 | <h2>row_array()</h2> | |
| 159 | ||
| 160 | <p>Identical to the above <var>row()</var> function, except it returns an array. Example:</p> | |
| 161 | ||
| 162 | <code> | |
| 163 | $query = $this->db->query("YOUR QUERY");<br /> | |
| 164 | <br /> | |
| 165 | if ($query->num_rows() > 0)<br /> | |
| 166 | {<br /> | |
| 167 | $row = $query->row_array(); | |
| 168 | <br /><br /> | |
| 169 | echo $row['title'];<br /> | |
| 170 | echo $row['name'];<br /> | |
| 171 | echo $row['body'];<br /> | |
| 172 | } | |
| 173 | </code> | |
| 174 | ||
| 175 | ||
| 176 | <p>If you want a specific row returned you can submit the row number as a digit in the first parameter:</p> | |
| 177 | ||
| 178 | <code>$row = $query->row_array(<dfn>5</dfn>);</code> | |
| 179 | ||
| 180 | ||
| 181 | <p>In addition, you can walk forward/backwards/first/last through your results using these variations:</p> | |
| 182 | ||
| 183 | <p> | |
| 184 | <strong>$row = $query->first_row()</strong><br /> | |
| 185 | <strong>$row = $query->last_row()</strong><br /> | |
| 186 | <strong>$row = $query->next_row()</strong><br /> | |
| 187 | <strong>$row = $query->previous_row()</strong> | |
| 188 | </p> | |
| 189 | ||
| 190 | <p>By default they return an object unless you put the word "array" in the parameter:</p> | |
| 191 | ||
| 192 | <p> | |
| 193 | <strong>$row = $query->first_row('array')</strong><br /> | |
| 194 | <strong>$row = $query->last_row('array')</strong><br /> | |
| 195 | <strong>$row = $query->next_row('array')</strong><br /> | |
| 196 | <strong>$row = $query->previous_row('array')</strong> | |
| 197 | </p> | |
| 198 | ||
| 199 | ||
| 200 | ||
| 201 | <h1>Result Helper Functions</h1> | |
| 202 | ||
| 203 | ||
| 204 | <h2>$query->num_rows()</h2> | |
| 205 | <p>The number of rows returned by the query. Note: In this example, <dfn>$query</dfn> is the variable that the query result object is assigned to:</p> | |
| 206 | ||
| 207 | <code>$query = $this->db->query('SELECT * FROM my_table');<br /><br /> | |
| 208 | echo $query->num_rows(); | |
| 209 | </code> | |
| 210 | ||
| 211 | <h2>$query->num_fields()</h2> | |
| 212 | <p>The number of FIELDS (columns) returned by the query. Make sure to call the function using your query result object:</p> | |
| 213 | ||
| 214 | <code>$query = $this->db->query('SELECT * FROM my_table');<br /><br /> | |
| 215 | echo $query->num_fields(); | |
| 216 | </code> | |
| 217 | ||
| 218 | ||
| 219 | ||
| 220 | <h2>$query->free_result()</h2> | |
| 221 | <p>It frees the memory associated with the result and deletes the result resource ID. Normally PHP frees its memory automatically at the end of script | |
| 222 | execution. However, if you are running a lot of queries in a particular script you might want to free the result after each query result has been | |
| 223 | generated in order to cut down on memory consumptions. Example: | |
| 224 | </p> | |
| 225 | ||
| 226 | <code>$query = $this->db->query('SELECT title FROM my_table');<br /><br /> | |
| 227 | foreach ($query->result() as $row)<br /> | |
| 228 | {<br /> | |
| 229 | echo $row->title;<br /> | |
| 230 | }<br /> | |
| 231 | $query->free_result(); // The $query result object will no longer be available<br /> | |
| 232 | <br /> | |
| 233 | $query2 = $this->db->query('SELECT name FROM some_table');<br /><br /> | |
| 234 | $row = $query2->row();<br /> | |
| 235 | echo $row->name;<br /> | |
| 236 | $query2->free_result(); // The $query2 result object will no longer be available | |
| 237 | </code> | |
| 238 | ||
| 239 | ||
| 240 | ||
| 241 | ||
| 242 | ||
| 243 | </div> | |
| 244 | <!-- END CONTENT --> | |
| 245 | ||
| 246 | ||
| 247 | <div id="footer"> | |
| 248 | <p> | |
| 249 | Previous Topic: <a href="queries.html">Queries</a> | |
| 250 | · | |
| 251 | <a href="#top">Top of Page</a> · | |
| 252 | <a href="../index.html">User Guide Home</a> · | |
| 253 | Next Topic: <a href="helpers.html">Query Helper Functions</a> | |
| 254 | </p> | |
| 255 | <p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2012 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p> | |
| 256 | </div> | |
| 257 | ||
| 258 | </body> | |
| 259 | </html> |